National Academies Press: OpenBook
« Previous: 1 Introduction
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

2

Current Protein Challenges

The first session of the workshop featured five presentations and two discussions on the role of protein in the diet; the effects of increasing the intake of alternative proteins on nutrition and health, on the environment, and on socioeconomic factors; and ethical considerations for alternative proteins related to technology, animal welfare, and sustainability. The session was moderated by Naomi Fukagawa, U.S. Department of Agriculture (USDA).

THE ROLE OF PROTEIN IN THE DIET

Dennis Bier, Baylor College of Medicine and the USDA/Agricultural Research Service Children’s Nutrition Research Center, reviewed protein features, dietary protein requirements, and challenges and considerations in measuring required protein. He opened by remarking that “without proteins, life would be impossible.” Bier explained that a long-held theory of the origins of life postulates the existence of a “primordial soup” in which chemical reactions initiated the synthesis of amino acids and proteins, which in turn became a biological process. He went on to describe a more recent theory positing that the ability of amino acids to oligomerize, replicate, and catalyze enabled chemical processes—involving ammonia and cyanide—that led to the initiation of life. Thus, he added, according to this theory, proteins have a role in the very essence of life.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Protein Functions and Features

Bier emphasized that proteins’ structural components and functional roles within organisms make them vitally important. Proteins are the structural component of the body and are required for any movement the body makes, he explained. He outlined the range of critical functions served by proteins. As enzymes, they catalyze essentially all metabolic reactions. Although some reactions can occur in the absence of proteins, achieving a rate necessary to maintain life requires the catalysis performed by proteins, which are the only macronutrient class with the capacity to catalyze reactions. As interorgan messengers, Bier continued, they enable movement and activity. Essential nutrients and nutrient functions are delivered by carrier proteins, such as lipoproteins that carry lipids through the bloodstream. Carrier proteins not only transport substances throughout the body, Bier explained; they also have active roles in the carrier process. For example, lipoprotein peptides play a role in the metabolism of lipoproteins themselves. Additionally, proteins have a role in immune function; as antibodies, they constitute the adaptive immune system.

Bier went on to observe that proteins that are consumed into the body are absorbed primarily as amino acids or di- or tripeptides. He noted, however, that on occasion, humans can absorb intact proteins with peptides that are longer than tripeptides. He added that it is not fully understood whether enterocytes (cells in the intestinal lining) can distinguish whether amino acids originated from an animal, plant, or other protein source. Furthermore, the capacity of intestinal microbiota to influence if and how enterocytes determine the source of protein has not been established. Bier highlighted the absence of a body storage reservoir for amino acids, which contrasts with the body’s ability to store carbohydrates and fats. For this reason, he said, alterations in protein intake require that the body either make more structural protein or excrete amino acids from the consumed protein. Every amino acid has a unique function in the body’s diverse metabolic pathways, he added; were this not the case, multiple amino acids would not need to exist.

Challenges in Measuring Protein Requirements

Bier provided an overview of challenges in measuring dietary protein requirements. He observed that, whereas the doubly labeled water method1 can be used to measure energy metabolism, no method is available for measuring protein adequacy and requirements in the free-living state. He added that the doubly labeled water method has a relative precision of

___________________

1 For more information about the doubly labeled water method, see IOM (1997).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

4–5 percent, which constitutes a relatively large amount of noise in the field of energy balance. He explained that dietary protein requirements have historically been assessed using nitrogen balance, a method used for more than 150 years to measure levels of this essential element in protein. Bier explained that nitrogen balance tends to be positively biased because of a tendency toward routine overestimates of actual nitrogen intake; furthermore, losses due, for example, to sweat and dermal cells are generally underestimated. Nitrogen balance is influenced by energy intake, he continued, and as a result, amounts of gain in nitrogen balance vary with respect to energy balance, so that nitrogen balance is not a one-to-one function. Additionally, Bier pointed out that a change in protein and nitrogen intake requires 5–7 days to yield a new steady state, posing logistical challenges and limiting studies that can be performed with humans.

Bier then described an alternative approach to assessing protein requirements that involves the use of labeled nitrogen or amino acid kinetics. Models are required to translate these measures to protein requirements, he explained, but the models are imperfect. Studies using these methods generally require the use of semisynthetic diets or constant feeding, neither of which mirrors the behavior of subjects in a free-living state. Moreover, Bier continued, the literature suggests that estimates of protein requirements based on amino acid kinetics are almost always greater than requirements determined via nitrogen balance. He remarked that he and others in the field have worked to understand why these differences occur but have been unable to progress from plausible hypotheses to unequivocal evidence.

Bier went on to explain that nonprotein nitrogen varies among foods, complicating the measurement of protein metabolism. Creatine, nucleotides, and other nonproteins can account for upward of 5–10 percent of nitrogen in foods. As a classic example of a nonprotein nitrogen source, Bier cited human milk, in which urea accounts for as much as 25 percent of nitrogen. He described a years-long controversy among professionals seeking to define protein requirements for infants as to whether the nonprotein nitrogen in human milk is usable. In the 1980s, Bier and colleagues conducted a study in which di-15N-urea was added to infant formula (Fomon et al., 1987). They found that within the first 3 days of consuming the formula, infants excreted 83 percent of the urea dose as di-15N-urea. According to Bier, this finding indicates that the infants did not utilize the nitrogen. He added, however, that foods contain a variety of types of nonprotein nitrogen, and in most cases, researchers have yet to understand how this affects requirement estimates.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Dietary Protein Requirements

Bier reiterated that nitrogen balance has long been used to measure protein requirements, noting that nitrogen balance, respiration, and calorimetry are among the few biological measurements in use for so long as research tools. In the late 1800s, he reported, several researchers demonstrated that irreversible or obligatory nitrogen losses were approximately 100 milligrams per kilogram of body weight per day (mg/kg/day). In 1981, the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) Joint Expert Consultation on Energy and Protein Requirements determined a nitrogen loss value of 54 mg/kg/day. Bier explained that because protein is 16 percent nitrogen, this nitrogen loss equates to a protein equivalent estimated average requirement (EAR) of 0.34 g/kg/day and a protein equivalent recommended dietary allowance (RDA) of 0.44 g/kg/day after accounting for population noise, digestibility, and other factors. Bier noted that in 2003, a meta-analysis of nitrogen balance summaries found an obligatory nitrogen loss of 105 mg/kg/day—similar to the 19th-century findings—and a protein equivalent EAR of 0.65 g/kg/day and RDA of 0.83 g/kg/day (Rand et al., 2003). He noted that in 2005, a Food and Nutrition Board/Institute of Medicine consensus study led to a recommended protein EAR of 0.66 g/kg/day and RDA of 0.80 g/kg/day (IOM, 2005).

Bier went on to describe how numerous studies have examined whether increasing protein intake carries benefit for people in various physiologic circumstances. He highlighted a study in which one group of older adults with a protein intake of 0.8 g/kg/day and another group with a higher protein intake of 1.3 g/kg/day showed virtually no change in lean body mass (LBM) (Bhasin et al., 2018). He also pointed to a meta-analysis of 74 studies that found no statistically significant effect on muscle mass from protein intake at levels ranging from 1.2 g/kg/day to 1.6 g/kg/day (Nunes et al., 2022). Bier added that in some cases, small increases in lean muscle mass were found in various muscle groups; overall, however, the studies reviewed found that raising protein intake above 1.2 g/kg/day causes no significant difference in muscle mass.

Conversely, Bier presented evidence indicating that inadequate protein intake can have detrimental effects on health. Decades of research on individuals with end-stage renal disease, for example, indicate a protein requirement similar to that of the general population, at an EAR of 0.6 g/kg/day and an RDA of 0.8 g/kg/day (Kovesdy et al., 2010). Bier observed that the high mortality rate among people with end-stage renal disease has enabled researchers to determine that the lowest relative hazard ratio for all-cause mortality is approximately 1 g/kg/day, indicating that consuming too little protein can increase mortality risk among this population.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Incomplete Proteins, Amino Acid Competition, and Digestibility

Bier next discussed incomplete proteins, amino acid competition, and digestibility in the context of alternative protein intake. He explained that incomplete proteins are abundant, with plant proteins being the classic example and the differences between grains and legumes being well documented. Although a corpus of research indicates that amino acids compete for absorption in the gastrointestinal tract, Bier noted that much of that literature predates current understanding of the structure and function of specific amino acid transporters. Recent research suggests, he pointed out, that some of the differences among amino acid digestibility stem from the distribution, number, and type of amino acid transporters—all potential factors that he stressed should be taken into account in considering the use of alternative proteins when protein sources are limited, when the overall protein supply is inadequate, or when the host is compromised by inborn errors of metabolism or gastrointestinal disease. He added that these factors may be more of a problem for those taking amino acid supplements, for whom amino acid balance is a more important issue. However, issues related to protein amino acid content or amino acid composition have not been shown to impair health in environments where protein availability is abundant, such as in high-income countries. Moreover, Bier continued, the digestibility of amino acids varies between about 60 and 90 percent across the plant community, and likely falls within that range among insects as well. For example, amino acids in mung beans and sunflower seeds have digestibility rates of 60–70 percent and 85–90 percent, respectively (Bandyopadhyay et al., 2022; Tessier et al., 2022).

Meeting Dietary Requirements with Alternative Protein Sources

Next, Bier considered whether adequate dietary protein intake can be achieved by consuming plant proteins. He noted that herbivores are common in the animal community, with animals such as the rhinoceros achieving their large, muscular statures through a plant diet. Furthermore, the composition of human diets worldwide indicates that it is possible to achieve adequate protein from plants. Thus, Bier contended, it is possible to construct a fully adequate protein diet from a wide variety of plant and animal sources. He identified principal constraints to meeting protein requirements with plants as (1) the amount of protein available per volume of food eaten, (2) the density of protein, and (3) the energy supplied by nonprotein sources. To illustrate, he cited a recent study suggesting that an intake of 20 grams of protein per day can be achieved through a combination of animal sources and high-quality nonanimal sources (e.g., eggs and soy) without substantially increasing total caloric intake; however, relying

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

on lower-quality protein sources (e.g., potatoes) can require up to a 10-fold increase in volume and caloric intake to achieve 20 grams of protein intake.

Considerations in Measuring Protein Intake from Alternative Protein Sources

Bier maintained that a reductionist approach to comparing plant- and animal-sourced proteins will fall short in answering key research questions about alternative sources of dietary protein, largely because of confounding environmental covariates, methodological noise propagated by current measurement methods, and the numerous environmental confounding variables in the exosome. To measure and study protein intake more accurately, Bier suggested developing outcome variables that, first, include a reliable estimate of LBM. He stated that while dual X-ray absorptiometry is the most common method of estimating LBM, total body potassium or nitrogen is a more direct measure. Second, Bier pointed to the need for an appropriate measure of function to capture changes in active cellular protein that may not be reflected in LBM. For instance, water is part of LBM, and an estimate of function is therefore needed to differentiate between active and water-based LBM. Bier concluded by reflecting that although the adequacy of alternative protein sources for meeting protein intake requirements has been established for decades, the public has been slow to adopt these protein sources, which demonstrates that human behavior and acceptance are major rate-limiting factors.

HEALTH AND NUTRITIONAL IMPACTS OF INCREASING ALTERNATIVE PROTEIN INTAKE IN THE DIET

Frank Hu, Harvard T.H. Chan School of Public Health, discussed the association between consumption of animal protein and chronic disease and mortality, nutritional differences among plant-based diets, and the nutritional content and health effects of plant-based meat alternatives. He described how, according to data from FAO, meat production and consumption have increased dramatically worldwide in recent decades—particularly in Asia and South America, regions where rapid economic development and the nutrition transition2 have paralleled increased consumption of meat. Hu characterized convergent global crises related to climate change and the food system as a “perfect storm,” with the current

___________________

2 The “nutrition transition” is described as the dietary changes that occur with increasing urbanization and rising incomes, whereby people are consuming more animal-source foods, sugar, fats and oils, refined grains, and processed foods. See Hawkes et al. (2017) for more information.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

demand for meat production expected to increase in conjunction with rapid population growth and economic development. He remarked that several features of the current food system, including the livestock sector’s significant contributions to greenhouse gas emissions, land and water use, and antibiotic resistance, make it unsustainable. He observed, moreover, that higher consumption of red meat is associated with a wide range of adverse health consequences (e.g., cardiovascular disease, cancer, other chronic diseases) that contribute to skyrocketing health care costs in the United States and other high-income countries. Simultaneously, he added, consumer demand for alternative proteins—especially plant proteins—is increasing because of concerns related to health, the environment, and ethics and animal welfare.

Health Benefits of Alternative Proteins

According to data from two large U.S. cohort studies, the average adult consumes approximately 18 percent of energy from protein, the majority of which derives from animal sources and only 20–25 percent from plant sources (Song et al., 2016). Since the mid-1980s, Hu reported, overall protein consumption in the United States has remained relatively stable, albeit with a slight decline in the consumption of animal protein coupled with a slight increase in plant protein consumption.

Hu stated that numerous epidemiological studies have reported relationships between protein consumption and risk of chronic diseases. For instance, he and his colleagues analyzed data from three cohort studies to determine whether total protein and type of protein consumed are associated with the risk of type 2 diabetes (Malik et al., 2016). After accounting for dietary fiber, dietary fats, body mass index, and other potential confounding factors, they found that higher consumption of animal protein tends to be associated with increased risk for this condition, whereas higher consumption of vegetable protein tends to be associated with lower risk. Similar patterns have been found for other chronic conditions, such as heart disease, stroke, and some cancers, Hu noted. He and his colleagues conducted statistical modeling to estimate the effects on mortality risk of replacing 3 percent of energy from various animal sources with plant protein (Song et al., 2016), and they found that replacing animal protein with plant protein is associated with significantly lower mortality (Song et al., 2016). They found that the largest benefit for reducing mortality risk was derived by replacing processed meats with plant protein; modest benefits in reducing mortality risk were associated with replacing unprocessed red meat, poultry, fish, eggs, and dairy with plant sources.

Hu explained that soy—one of the most popular plant protein sources—contains high-quality protein as well as isoflavones, which may

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

have independent benefits for reducing cardiovascular risk factors. He and his colleagues found that higher consumption of isoflavones and soy products was associated with significantly lower risk of heart disease (Ma et al., 2020). Hu noted that this research included three large cohort studies, which provided both a sufficient sample size to account for the relatively low consumption of soy in the U.S. population compared with Asian populations and a long duration of follow-up in which to detect health benefits. According to Hu, the finding that relatively high consumption of soy products conveys significant health benefits suggests that soy products can be integrated into healthy plant-based diets as an important source of protein that aids in the prevention of heart disease.

Hu went on to report that numerous randomized controlled trials (RCTs) with small sample sizes have examined the effects of plant protein sources on cardiovascular risk factors. As an example, he cited a meta-analysis of RCTs on plant foods and blood lipid levels, which found that substituting plant protein sources, such as tree nuts, walnuts, almonds, and soy products, for red meat significantly reduced total and low-density lipoprotein (LDL) cholesterol levels by 5–10 percent—a clinically significant reduction in terms of reducing the risk of cardiovascular disease (Guasch-Ferré et al., 2019). Hu explained that plant protein sources contain numerous beneficial nutrients and bioactive compounds—such as fiber, saturated fatty acids, phytosterols, tocopherols, polyphenols, and minerals—that are known to confer a wide range of cardiovascular benefits, including reducing oxidation, chronic inflammation, blood pressure, and insulin resistance (Ros and Hu, 2013).

Healthy Plant-Based Diets

Hu emphasized that although plant-based diets have been widely recommended to reduce the risk of chronic diseases, not all plant-based diets are healthy, and unhealthy plant-based diets may increase the risk of those same chronic diseases. He and his colleagues developed two indices of diet quality to qualify healthy versus unhealthy plant-based diets (Satija et al., 2016). A healthy plant-based diet is characterized by high intake of high-quality plant foods, such as fruits, vegetables, whole grains, nuts, and legumes. Unhealthy plant-based diets are characterized by high intake of heavily processed carbohydrate foods, plant foods with a high glycemic index, and added sugar. Hu’s group found that a healthy plant-based diet significantly reduces the risk of type 2 diabetes and heart disease, while its unhealthy counterpart increases the risk of those diseases (Satija et al., 2016).

Hu observed that, to improve both human and planetary health, advisory bodies have in recent years recommended plant-based dietary patterns.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

He highlighted as an example the 2015 Dietary Guidelines Advisory Committee (DGAC), which used available evidence in recommending several plant-based dietary patterns to reduce the risk of chronic diseases and the environmental effects of the typical U.S. diet. Examples of recommended dietary patterns that are expected to have benefits for both human health and environmental sustainability include those based on Dietary Guidelines for Americans (DGA), as well as healthy vegetarian, Mediterranean-style, and Dietary Approaches to Stop Hypertension diets. Hu added that recommendations on environmental sustainability were excluded from the official DGA.3 Similarly, the EAT-Lancet Commission recommended the Planetary Health Diet to improve both human and planetary health. In comparison with current global dietary consumption patterns, the Planetary Health Diet requires a 50 percent reduction in red meat consumption and a two-fold increase in plant-based foods such as fruits, vegetables, nuts, and legumes. In reviewing these recommendations, Hu remarked on the importance of tailoring them to local circumstances. For example, U.S. consumption of red meat is several times higher than the amount recommended by this diet, whereas some countries in South Asia consume only half of the recommended levels of red meat.

Emergence of Plant-Based Meat Alternatives

Hu next considered the emerging role of plant-based meat alternatives as protein sources. Ideally, he stated, animal protein sources should be replaced by whole or minimally processed plant protein sources, such as nuts, seeds, legumes, and soy products. Given the current U.S. food system and consumer behaviors, however, he suggested that this change is not feasible. Thus, he predicted that plant-based meat alternatives and other existing and emerging alternative protein sources, such as mycoprotein, insect protein, algae protein, and laboratory-grown or cultivated meat, will be instrumental in meeting the increasing global protein demand, with the potential to help reduce environmental impacts associated with traditional meat production.

In recent years, Hu noted, plant-based meat alternatives produced by Impossible Foods and Beyond Meat have become popular as a result of product engineering that replicates the taste and texture of animal meat. Hu and his colleagues conducted research on whether such plant-based meat alternatives can be part of a healthy and sustainable diet (Hu et al., 2019). Based on life-cycle analysis, they found that replacing red meat with

___________________

3 More information about this decision can be found in Secretary Tom Vilsack and Secretary Sylvia Burwell’s statement at https://www.usda.gov/media/blog/2015/10/06/2015-dietary-guidelines-giving-you-tools-you-need-make-healthy-choices (accessed December 15, 2022).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

plant-based meat alternatives holds potential for reducing greenhouse gas emissions, energy use, water use, and land use. However, Hu pointed out, the nutrient composition of plant-based meat alternatives currently is not optimal because of high amounts of sodium and saturated fat. Furthermore, these products are typically heavily processed and often consumed in fast food settings. Hu cautioned as well that the high amount of heme iron in Impossible Foods is a possible cause for concern, given that studies have shown higher consumption of heme iron to be associated with increased body iron stores and increased risk of type 2 diabetes.

Nutritional Effects of Replacing Meat with Plant-Based Meat Alternatives

Hu next described how several studies have modeled the nutritional effects of switching from animal- to plant-based proteins. He cited a study that used National Health and Nutrition Examination Survey (NHANES) data to model the nutritional effects of substituting for animal products in the current U.S. diet either traditional or novel (i.e., developed recently or by innovative processing methods) plant-based meat alternatives (which included products intended to mimic traditional protein sources, such as plant-based egg alternatives, beef jerky, and burgers) to create flexitarian,4 vegetarian, and vegan diets (Tso and Forde, 2021). The study found that with the exception of traditional vegan diets, diets based on traditional plant-based substitutes met daily requirements for vitamins and minerals and were lower in saturated fat, sodium, and sugar compared with the reference omnivore diet (based on 2017–2018 NHANES data). The study found further that diets built on novel plant-based meat alternatives were below daily requirements for calcium, potassium, magnesium, zinc, and B12, and exceeded the reference diet for saturated fat, sodium, and sugar. The authors concluded that plant-based diets with larger proportions of novel plant-based meat alternatives run the risk of being inadequate sources of several important micronutrients. Hu added that this was also the case for traditional vegan diets in the absence of nutritional supplements.

Hu highlighted another modeling study that projected the nutritional effect of shifting from typical meat consumption levels in the United Kingdom to more meat-alternative products, including vegetable proteins; mycoprotein; and a combination of legumes, tofu, nuts, and soy (Farsi et al., 2021). The models predicted this shift would result in significant increases in fiber intake and a significant decrease in saturated fat intake. The model also projected significant reduction in total protein and vitamin B12 intake and increased intake of sodium and added sugars. The authors

___________________

4 A flexitarian diet includes intermittent meat consumption and multiple days per week on which no meat is consumed.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

recommend using a variety of protein-alternative products and selecting products that are high in protein and fiber and low in saturated fat and added sugar, and contain substantial amounts of iron and B12.

Health Effects of Replacing Meat with Plant-Based Meat Alternatives

Hu reported that, to date, only one RCT has been conducted to compare the effects on cardiovascular risk factors of plant-based meat alternatives versus red meat (Crimarco et al., 2020). This trial, conducted at Stanford University and funded by Beyond Meat, assessed 36 participants who were instructed to follow two diets for 8 weeks each. One diet included two servings per day of red meat, while the other included two servings per day of plant-based meat alternatives, which included plant-based products analogous to burgers, sausages, and chicken strips. Participants were instructed to keep all other foods and beverages consumed throughout the 16 weeks as similar as possible. According to Hu, the study found that replacing red meat with plant-based meat alternatives was associated with a significant reduction in plasma concentrations of trimethylamine-N-oxide, a gut flora metabolite associated with increased risk of cardiovascular disease. Additionally, LDL cholesterol concentrations decreased by approximately 10 percent, and a small reduction in body weight occurred. Hu remarked that these findings are promising but suggested that larger and longer-term studies are needed to replicate them.

Hu noted that multiple clinical studies have been conducted on mycoprotein and health biomarkers. Mycoprotein, first discovered in the early 1960s, is derived from fungi through fermentation. Hu reported the results of a systematic review of 16 RCTs with a total of 432 participants, which found that acute mycoprotein ingestion significantly reduced subsequent energy intake (Derbyshire and Delange, 2021). In comparison with animal protein, short-term interventions with mycoprotein significantly lowered total and LDL cholesterol levels, especially among participants with hyperlipidemia. Hu added that the evidence was less conclusive for effects on blood glucose and insulin levels.

Exploring Pros and Cons of Different Alternative Protein Sources

Hu outlined health benefits and factors to consider for various alternative protein sources, including plant-based meat alternatives, mycoprotein, insects, algae, and laboratory-grown meat (Table 2-1). He observed that compared with meat, plant-based meat alternatives have comparable protein content, more fiber, no cholesterol, and no added hormones and antibiotics, and often have less saturated fat. However, he noted, these highly processed products typically contain high amounts of sodium and additives

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

TABLE 2-1 Pros and Cons of Different Alternative Protein Sources

Pros Cons
Plant-based meat
  • Comparable protein content to meat
  • More fiber and less saturated fat; no cholesterol
  • No added hormones and antibiotics
  • May contain high amounts of sodium and additives
  • Lower amounts of B12, zinc, and iron if not added
  • Highly processed
Mycoprotein
  • Contains all essential amino acids; high digestibility/bioavailability
  • Low in saturated fat and cholesterol; high in fiber, zinc, B12, and choline
  • Possibility of allergy (rare)
Insects
  • Good source of protein, PUFA, vitamins, and minerals
  • Nutritional values vary
  • Possibility of allergy
  • The yuck factor
Algae
  • Good source of protein, PUFA, and fiber
  • Source of vitamin B12 and iodine
  • Low raw digestibility and may contain some pollutants
  • Nutritional values vary
Lab-grown meat
  • Foodborne diseases can be reduced
  • Nutritional composition can be tailored
  • Little is known about its health effects
  • Cost

NOTE: PUFA = polyunsaturated fatty acid.

SOURCE: Presented by Frank Hu on August 17, 2022. Adapted from https://www.eitfood.eu/blog/are-alternative proteins-good-for-you (accessed October 31, 2022).

and, unless added, lower amounts of B12, zinc, and iron compared with meat.

Turning to mycoprotein, Hu stated that it contains all essential amino acids and has high digestibility. Furthermore, he said, mycoprotein products are typically low in saturated fats and high in fiber, zinc, and B12. Hu reiterated that clinical studies have shown that mycoprotein can reduce total and LDL cholesterol levels, but he added that longer-term clinical studies are needed. He noted further that mycoprotein allergies are rare but do occur.

Insects are a good source of protein, polyunsaturated fat, vitamins, and minerals, Hu observed. He noted that the nutritional value of insect protein varies depending on the species, and only limited human and clinical data on this protein source are available to date. He added that many consumers are repulsed by the idea of consuming insects, and this aversion may be difficult to overcome.

Algae are a good source of protein, omega-3 fatty acids, B12, and fiber, Hu continued, and small trials have shown some metabolic benefit from

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

the consumption of seaweed. However, he said, algae have relatively low raw digestibility and may contain contaminants, and their nutritional value varies by species.

Finally, Hu explained that laboratory-grown meat may reduce the risk of foodborne diseases that can occur with meat, and its nutritional composition can be tailored. However, he observed, it is expensive, and limited information is currently known about its effects on health.

Envisioning a Healthy and Sustainable Food System of the Future

Hu concluded by highlighting key findings about alternative proteins in the diet thus far, then envisioning their possible role in the food system of the future. He warned that the current animal protein–oriented food system is not sustainable given population growth, effects on health, and degradation of and demand on the environment. It is well established, he assented, that diets rich in minimally processed plant foods tend to have the largest health benefits and the lowest environmental impact compared with other dietary patterns. Thus, as the global demand for meat continues to increase, Hu posited that alternative proteins could play an important role in meeting demand while limiting deleterious environmental impacts. However, he emphasized that highly processed plant-based meat alternatives are not a substitute for minimally processed, whole plant foods, and that diversifying protein sources is important given the pros and cons of the various options. Furthermore, he encouraged a focus on overall diet quality, of which the quality and quantity of protein are important components.

According to Hu, the longer-term positive and negative impacts of alternative proteins on human and planetary health remain to be seen, and—importantly—a fundamental change in the food system requires not just technological innovation but also policies to create a food environment in which healthy and sustainable food choices are accessible and affordable. Finally, he mused that “today we are looking for healthy and sustainable meat alternatives, but we can envision a future where meat becomes the alternative.”

DISCUSSION

The discussion following the presentations summarized above focused on protein absorption and allergies, protein in healthy versus unhealthy plant-based diets, protein intake and brain function, regional differences in protein quality, and longitudinal studies on protein and health.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Protein Absorption and Allergies

A participant remarked on the general understanding that proteins are not absorbed in whole form, yet allergic reactions to whole proteins or large segments of proteins can occur, as in the case of cow’s milk. The participant asked whether such allergies indicate that proteins are absorbed intact more often than has historically been understood. Bier referenced well-documented examples of absorption of fully intact proteins and peptides greater than di- and tripeptides, including one study that used mass spectrometry to examine the protein excreted in urine and found that protein was absorbed intact. He noted that research has yielded examples of specific protein epitopes responsible for the allergic phenomenon, a finding that does not necessarily involve the intact protein, and added that the effect of sensitization of infants to proteins (e.g., peanuts) on the risk of later reactions has also been studied. Bier cautioned that the potential for allergies should not be overlooked: food scientists are using algorithms for reducing the risk of allergy, but the risk of allergies is present with all foods. He described how approximately 30 years ago, food scientists in the field of genetically modified transgenic foods developed an algorithm for reducing the introduction of new antigenic foods into the food supply, and this algorithm could be employed in creating new proteins. Hu commented on the need for monitoring for allergies and any other unintended consequences as new technologies are used to create novel alternative protein products.

Protein in Healthy versus Unhealthy Plant-Based Diets

Fukagawa asked Hu about the amounts of protein observed in his research on healthy versus unhealthy plant-based diets. Hu noted that a healthy plant-based diet contains a higher amount of plant protein compared with the unhealthy diet. He explained that his group looked at the quality of plant foods such as fruits, vegetables, whole grains, nuts, and legumes. A healthy plant-based diet has a large amount of unprocessed or minimally processed plant foods, whereas the unhealthy plant-based diet contains a large amount of highly processed and ultraprocessed plant foods. Hu added that processing removes some beneficial nutrients from plant foods and adds saturated fat, sugar, and sodium.

Protein Intake and Brain Function

In response to a question about the effects of high versus low protein intake on brain function or mental health metrics, Bier said he was unaware of any clinical findings of clear differences in effects for protein intake within the range of 0.8–1.6 g/kg/day, which applies to most of the world’s

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

population. In some Asian countries, he noted, protein intake is slightly above the requirement level, whereas in the United States, it is two- or three-fold higher than the requirement. However, while small differences in specific variables within these groups have surfaced, their clinical significance is uncertain. Hu added that most human studies have focused on the relationship between amounts or types of protein and the risk of chronic disease, particularly with respect to heart disease, cancer, renal disease, and bone health, and noted that the data on mental health and neurodegenerative disease are comparatively limited. Given that amino acids such as tryptophan are precursors to neurotransmitters such as serotonin and melatonin, he suggested that a theoretical basis exists for the relevance of those amino acids to mental health and long-term risk of neurodegenerative diseases, although data in this regard are limited.

Regional Differences in Protein Quality

A participant asked whether regional differences are present in the essential nutrients in protein. Bier replied that regional differences apply to urban environments, with some people having and others lacking access to fresh produce. Hu remarked that the amount and quality of protein varies across U.S. regions. Additionally, he argued that protein intake should be considered in the context of overall diet quality, including carbohydrate and fat intake, as people who consume a high-quality diet tend to consume high-quality protein, fats, and carbohydrates.

Longitudinal Studies on Protein and Health

In response to a question about longitudinal studies on the effect of increased protein intake on clinically healthy subpopulations, Hu stated that many epidemiological studies have examined the relationship between protein intake and the long-term risk of chronic disease. These observational studies have followed cohorts for years or decades to identify associations between protein intake and subsequent risk of chronic diseases. Hu suggested that ideally, a large RCT would be conducted to confirm these associations, but this type of study is infeasible because of cost considerations and compliance issues. He added that data from long-term epidemiological studies converge with evidence from small RCTs to indicate that certain healthy dietary patterns that include high-quality plant protein have beneficial factors on long-term disease risk.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

ENVIRONMENTAL IMPACTS OF INCREASING ALTERNATIVE PROTEIN INTAKE IN THE DIET

Zach Conrad, William & Mary, examined the environmental impacts of increasing alternative protein intake in the diet. He critically appraised the diet-sustainability hypothesis, which holds that healthy diets are more environmentally sustainable relative to typical diets, and outlined a timeline of evidence for this hypothesis and its implications for alternative protein sources.

According to Conrad, despite early claims that healthier diets are more environmentally sustainable, a growing body of evidence suggests this is not always the case. He added that although the general public and many scientists often consider greenhouse gas emissions as the predominant measure of environmental sustainability, other indicators are useful for this purpose, including soil erosion, energy use, air pollution, water pollution, nutrient loss, eutrophication,5 fertilizer use, pesticide use, water use, water scarcity, and biodiversity. Conrad asserted that further advances in diet-sustainability analyses will depend on the ability of researchers to link sustainability indicators to actual rather than theoretical dietary patterns, evaluate incremental shifts toward meeting dietary guidelines rather than perfect compliance, include multiple measures of healthy eating and environmental impact, develop robust methods for measuring bias, and initiate systemic change in institutions to adequately train the next generation of sustainability scientists.

Evolution of Evidence for the Diet-Sustainability Hypothesis

Conrad used the diet-sustainability hypothesis to explore the relationship between environmental sustainability and diet quality. He pointed out that although the hypothesis that healthy diets are more environmentally sustainable has been posited for more than a century, a seminal article in 1986 transformed the hypothesis into conventional wisdom (Gussow and Clancy, 1986). He then charted the evolution of evidence supporting this claim through a critical lens.

In 2015, Conrad reported, the Scientific Report of the USDA Dietary Guidelines Advisory Committee (DGAC) cited consistent evidence that a diet higher in plant-based foods and lower in animal-based foods promotes health and is associated with less environmental impact. He noted that the report drew on 15 studies, yet only 2 of these evaluated the U.S. context, including one that focused on a single state. In 2016, he continued, several

___________________

5 Eutrophication is excessive density of nutrients in a body of water, typically due to runoff from the land, resulting in a lack of oxygen that causes death of animal life.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

DGAC panelists published a separate systematic review of studies on the environmental sustainability of healthy dietary patterns, reporting that the results of the studies they had evaluated were consistent with the finding of the 2015 DGAC report that greater consumption of animal-based foods is associated with greater environmental impact (Nelson et al., 2016). Conrad added that the review also pointed to evidence that the authors claimed demonstrates that health-promoting dietary patterns improve environmental sustainability. Conrad noted that this review included three U.S. studies, but they did not feature nationally representative diets; instead, the diets included in these studies were variations of a plant-based or vegetarian eating pattern (Peters et al., 2007; Pimentel and Pimentel, 2003; Sabaté and Soret, 2014). According to Conrad, all the studies reviewed found that healthier diets were associated with less water use, land use, energy use, and greenhouse gas emissions.

Conrad then turned to an additional systematic review, published in 2020, that reflected a large increase in the number of studies investigating the relationship between healthy diets and sustainability, both internationally and in the United States (Reinhardt et al., 2020). That review, he said, summarized conclusions from these 23 studies, one of which was a lack of support for prior findings that diets adhering to national dietary guidelines are necessarily more sustainable than the average U.S. diet. Additionally, he reported, the review found that these studies support previous findings that dietary patterns higher in plant-based foods benefit environmental sustainability.

Conrad also described a 2018 study that evaluated various protein sources in terms of multiple indicators of environmental sustainability, including climate change, land use, water depletion, freshwater eutrophication, marine eutrophication, and particulate matter (Blackstone et al., 2018). That study found that red meat has a greater effect on climate change, land use, and particulate matter relative to other protein sources, such as eggs, nuts and seeds, soy, and legumes. Conrad noted that although some plant-based protein sources, such as nuts and seeds, have a greater effect on water usage compared with most other protein sources, this same group has a lesser effect on climate change, land use, freshwater and marine eutrophication, and particulate matter.

Conrad emphasized that although the relationship between healthy diets and sustainability is being reevaluated, the link between animal-based foods and sustainability has remained largely unchanged as evidence continues to accrue. At the same time, however, he underscored the importance of considering the specific environmental indicators used in different studies, as well as how these data are being normalized across different environmental sustainability indicators. For instance, normalized total protein intake is a useful comparator, but others could also be valuable.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Conrad also suggested that researchers carefully consider the sources of evidence used in making claims about healthy and sustainable diets.

Considerations for Future Research on Sustainable Diets

According to Conrad, many questions regarding sustainable diets remain unanswered. As examples, he observed that it has not yet been established whether sustainability indicators can be linked to actual—rather than theoretical—dietary patterns, nor is it known whether nationally representative samples are being used to inform national dietary guidance. More research is needed, he asserted, to ascertain whether the diet-sustainability hypothesis holds when evaluated based on incremental shifts between the average diet and the diet specified by the guidelines. He added that the consistency of sustainability outcomes across different measures of healthy eating also is not fully understood.

In an attempt to answer some of these questions, Conrad and colleagues carried out a study examining four indicators of environmental sustainability: use of agricultural land, fertilizer, pesticides, and irrigation water (Conrad et al., 2020). They used two measures of healthy eating—the Healthy Eating Index (HEI) and Alternative Healthy Eating Index (AHEI)6—to establish quintiles of diet quality, which were then assessed for effects on environmental sustainability indicators (Figure 2-1). For both the HEI and AHEI, the study found that as diet quality increased, land use decreased. No statistically significant relationships emerged between fertilizer use and the foods making up the HEI diet; however, as the quality of the AHEI diet increased, fertilizer use decreased. Use of both pesticides and irrigation water increased with a higher-quality HEI diet, whereas no statistically significant relationship was identified between these two measures and the AHEI diet.

Conrad then presented a set of research questions for which answers would help improve the evidence base for the diet-sustainability hypothesis. He suggested, for instance, evaluating the usefulness of isolating protein sources from dietary patterns. He argued that although it may be useful in some circumstances to investigate specific protein sources independently of the context of the total diet, studies investigating total dietary patterns should not be excluded from the body of evidence. He also suggested that developing the ability to create measurements of sustainability would include multiple indicators instead of considering only greenhouse gas

___________________

6 More information about the HEI is available at https://www.fns.usda.gov/healthy-eating-index-hei. More information about the AHEI is available at https://www.health.harvard.edu/blog/scoring-highly-on-alternative-healthy-eating-index-lowers-risk-for-many-illnesses-202202082681 (accessed September 26, 2022).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Image
FIGURE 2-1 Annual amount of various agricultural resources used to produce total food demand, by Healthy Eating Index (HEI)-2015 (top) quintile and Alternative Healthy Eating Index (AHEI)-2010 (bottom) quintile.
SOURCE: Presented by Zach Conrad on August 17, 2022, from Conrad et al., 2020.
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

emissions. Additionally, Conrad stressed that effects from all stages of the food system warrant study. His research has focused on data from the agricultural stage of the food system, as is the case with much research in this area, and there are some limited data from the retail and consumer stages, but data from the processing and manufacturing stages, though increasing, remain incomplete. Conrad also emphasized the importance of measuring and controlling for bias and error when integrating data and analytic methods from different disciplines, as well as accounting for bias embedded in each data source and analytic technique when integrating multiple data sources and techniques. He suggested that appropriately capturing combined error during the process of integrating data sources for diet-sustainability analyses may require the establishment of reporting guidelines for sustainability studies, as has been done for other types of study designs.

Conrad proposed that the development of dietary guidance should balance potential trade-offs between achieving nutrition and sustainability outcomes. He also asserted that when results vary for different sustainability indicators, claims about the relationship between healthy eating and sustainability should take these varying results into account to avoid overgeneralization. For example, if—theoretically—consuming more vegetables is associated with improved environmental sustainability outcomes, the practical differences among varieties of vegetables should be established to better inform consumers. In implementing dietary suggestions, Conrad pointed out, consumers often want specific recommendations regarding produce to add to their diet. According to Conrad, such practical considerations and public communication strategies are often unresolved.

Training the Next Generation of Food System Scientists

Conrad concluded by highlighting the need to provide the next generation of scientists with the interdisciplinary tools and institutional support they need to address the lingering research questions related to sustainable diets. He stressed that this support should include offering opportunities for interdisciplinary and multidisciplinary education rather than encumbering students with the responsibility of piecing together a curriculum to meet their needs within narrow disciplinary confines. For example, a student studying sustainable food systems in an institution without an interdisciplinary approach might have to major in biology and take supplemental nutrition and agriculture courses from other departments. Conrad also suggested providing interdisciplinary training opportunities for fellows, interns, and research assistants, as well as developing tools and analytic methods that would enable students to answer research questions in graduate, doctoral, and postdoctoral programs. He added that within academia, professional positions are traditionally departmental, and more interdepartmental

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

positions are needed for interdisciplinary work. Conrad described the need for more and varied leadership positions, and he suggested using professional societies as a mechanism for establishing interdisciplinary collaborations and connections. Finally, he pointed to the need to fund interdisciplinary research and to provide outlets for interdisciplinary, peer-reviewed publications to conduct and disseminate sustainability research.

SOCIOECONOMIC IMPACTS OF INCREASING ALTERNATIVE PROTEIN INTAKE IN THE DIET

Jayson Lusk, Purdue University, explored the socioeconomic impacts of increasing the intake of alternative proteins. He began with an overview of the economics of protein production in the United States, including agricultural land use, the current agricultural economy, farmers’ attitudes toward various protein sources, consumer purchasing habits and preferences, and market trends for alternative proteins. He explained that most dietary protein consumed in the United States is derived from animal sources, with poultry and meat as the top sources, followed by bread products, milk, cheese, eggs, plant-based protein foods, and seafood (Pasiakos et al., 2015). When the data are aggregated by animal, dairy, or plant-based sources, more than 80 percent of U.S. protein consumption comes from animal and dairy foods (Phillips et al., 2015). Lusk noted that protein quality varies, and statistics based solely on grams of protein consumed do not account for quality.

The U.S. Agricultural Economy

Lusk reported that the two most widely grown U.S. crops by acreage, according to the USDA National Agricultural Statistics Service, are corn and soybeans. He added that while the production of wheat has been decreasing over the past two decades, it remains the third largest crop, and the production of oats, cotton, and barley has also declined in the past half century. Fruit, vegetable, and nut crops account for a total of less than 1 percent of all acres planted. Lusk reported that crop planting accounts for approximately 43 percent of all U.S. agricultural land use, whereas about 45 percent is used for permanent pasture and 8 percent is wooded forestry land. Looking at the proportion of total cropland, Lusk noted that more than 80 percent is used for planting wheat, corn, and soybeans; thus, farmers are earning income and receiving incentives primarily for the production of these three crops.

Lusk went on to report that, in 2020, according to the USDA World Agricultural Supply and Demand Estimates, U.S. farm commodity receipts totaled $364 billion. He noted that approximately 45 percent of dollars

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

received was for animal production—beef, pork, chicken, dairy, or eggs. Lusk remarked that the animals used in animal production require a food supply that constitutes a large portion of farm receipts. In 2020, he said, feed grains accounted for $58 billion in sales and 16 percent of total commodity receipts. He reported that approximately 45 percent of domestic corn is fed directly to animals. Ethanol production utilizes about 40 percent of feed grain sold, with 20 percent of corn reaching animals indirectly via distillers’ grains. Soybeans constitute about 11 percent of total farm receipts, at $42 billion, with approximately 85 percent of soybean production being devoted to animal feed for use in both the United States and abroad. Lusk emphasized that 68–70 percent of total U.S. farm receipts is derived from animal production and livestock feed. With respect to direct protein sources derived from plants, he noted that a small percentage of soybean production is used directly as a human food source; human food grains such as wheat, rice, and rye account for about $11.8 billion in sales, or 3 percent of total receipts. Similarly, nuts such as almonds, pistachios, walnuts, peanuts, and pecans account for 3 percent of total receipts, or $11.2 billion. Lusk pointed out that although these figures signify that alternative proteins are being produced, they represent a small share of the total current agricultural economy.

Lusk went on to observe that some advocates for plant-based protein have made an efficiency argument—that the protein and energy involved in feeding livestock could theoretically be rerouted to humans, so that fewer farm acres would have to be devoted to feed grain crops. He explained that 80–90 million acres of soybeans are produced annually in the United States, adding that if all beef burgers were replaced with burgers made from soy-based protein and if soybeans were then used directly as human food instead of being fed to cows, less than 5 million acres of soybeans would be required. According to Lusk, although this observation supports the efficiency argument, it raises questions about farm profitability in the context of a dramatic reduction in income for soybean farmers. He pointed out, moreover, that acreage devoted to some plant protein crops could increase if those crops were substituted for animal protein. To illustrate, he noted that if beef burgers were replaced by pea protein, acres used for dry pea production would increase from about 1 million to more than 5 million, yet this increase would not compensate for the loss of income farmers would face given that soybean production currently accounts for 80–90 million acres planted annually.

Agricultural Economics of Various Protein Sources

Turning to the agricultural economics of various protein sources from the perspective of farmers, Lusk reported that the Purdue University

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Center for Commercial Agriculture has included questions about perceptions regarding the emergence of novel plant-based proteins in its monthly survey of 400–500 farmers (Mintert and Langemeier, 2021). One question poses a scenario in which plant-based meat alternatives account for 25 percent of the overall protein market and asks participants about what effect they would expect this scenario to have on U.S. aggregate net farm income, a broad measure of farm profitability. Approximately 61 percent of respondents said they expected farm income would fall, and an additional 30 percent said they expected no change in income. Thus, the majority of respondents did not expect that replacing animal proteins with plant-based proteins would benefit farm profitability.

Lusk pointed out that while plant-based proteins could decrease sales of livestock grain feed, they also present agricultural opportunities. The survey asked farmers whether they would accept a contract to grow crops to produce a plant-based meat alternative if it were offered. Approximately 62 percent of respondents said they would not accept such a contract, 16 percent said they might accept, and 23 percent said they would accept. Lusk expressed doubt that two-thirds of farmers would reject an actual—versus a theoretical—contract, but he suggested that these survey responses reflect underlying negative attitudes within the farming community toward plant-based protein products and that this negative perception is likely associated with an understanding of how much of the agriculture economy is currently driven by the production of animal protein.

Lusk underlined the relevance of considering consumer preferences when conducting cost–diet studies and comparing optimal and hypothetical diets. He presented data from a 2009 study calculating the cost of producing various protein sources for retail consumption, and he noted that the ranking of these commodities is highly representative even though the prices used in the study are not current (Lusk and Norwood, 2009). He reiterated that the quality of protein varies and pointed out that this study used volume of protein, not quality, as a measure. In terms of retail cost per gram of protein, Lusk observed that, according to this study, plant-based crops—including corn, soybeans, wheat, and peanuts—are less expensive than animal-based sources of protein; chicken is an exception and is comparable in price to plant-based protein sources. Thus, when one considers the cost of protein per gram in isolation, this study indicates that plant-based sources are the least expensive option. However, Lusk emphasized that consumers base purchases on factors beyond cost and nutrient content. He noted that this study used data from actual consumer purchases in economic modeling of consumers’ willingness to pay to maintain various categories of food products in their diet. The models used in this study indicated that consumers are willing to pay more to keep meat in their diet relative to any other food category, he added. Therefore, Lusk

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

said, although plant-based protein sources are more affordable, consumers have strong preferences for the taste and other attributes of animal-based sources of protein.

In research comparing actual spending patterns of people on an average diet, on a partial vegetarian diet, and on a full vegetarian diet, Lusk found that spending does not always decrease for people who eat less meat (Lusk and Norwood, 2016). In this study, self-declared partial vegetarians spent the most on groceries—an average of $39.67 more per week than that of consumers who did not indicate any level of vegetarian status. However, consumers who indicated that they adhered strictly to a vegetarian diet spent $19.28 less per week on groceries compared with those on a typical diet.

Lusk next reported the results of a monthly, nationally representative survey of 1,000 U.S. food consumers, conducted by the Purdue University Center for Food Demand Analysis and Sustainability (CFDAS), that asks how often participants choose plant-based over animal-based proteins.7 Only 10 percent of respondents indicated that they always opt for plant-based proteins, whereas 33 percent never did so. Lusk explained that the CFDAS survey data dashboard enables aggregation of data based on a variety of socioeconomic factors, including age. He noted that participants’ survey responses varied greatly by age, with 17 percent of respondents ages 25–34 indicating that they never opt for plant-based over animal proteins, compared with 54 percent of those ages 75 and older (Figure 2-2). Lusk remarked that this finding is consistent with results of other research indicating that novel plant-based proteins are particularly popular among younger consumers.

Market Trends for Plant-Based Meat Alternatives

Lusk next outlined market trends associated with novel plant-based meat alternatives. Ground beef alternatives are most popular, he observed, with plant-based turkey, chicken, and pork alternatives representing a smaller portion of sales. He reported that according to household scanner data that reflect actual purchase patterns, novel plant-based ground meat alternatives have seen a strong increase in market share of ground meat sales, doubling from 4 percent in 2018 to 8 percent in 2020 (Neuhofer and Lusk, 2022). Lusk remarked that this increase reflects both enthusiasm about these novel products in the market and an influx of investment capital in the plant-based meat-alternative industry.

Using data from IRI for August 2021 through July 2022, however, Lusk calculated year-over-year change—that is, weekly grocery store sales in a

___________________

7 More information about the CFDAS survey is available at https://ag.purdue.edu/cfdas/data-resources/consumer-food-insights/ (accessed September 30, 2022).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Image
FIGURE 2-2 Center for Food Demand Analysis and Sustainability survey responses by age.
SOURCE: Presented by Jayson Lusk on August 17, 2022, from the Center for Food Demand Analysis and Sustainability, Purdue University.
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

given week compared with the same week 1 year prior—in sales of pork, chicken, beef, and meat alternatives and found that sales of the latter had dropped since 2021 (Figure 2-3). The reasons for this decline, he said, are not readily apparent. He stated that he has been tracking consumer choices over time through research that involves surveying participants about simulated shopping experiences.8 Participants are asked to choose proteins to purchase from a list of items and associated prices that are varied to make it possible to gauge consumer willingness to pay and account for price elasticities of demand. According to Lusk, based on average prices, chicken breast and ground beef are the most popular protein options—representing about half of total responses—whereas the rate at which participants select the plant-based protein patty has hovered around 3 percent for the past 2 years. Thus, he said, this research does not indicate a significant demand shift toward plant-based meat patties. Lusk noted that this finding does not preclude the possibility of sales growth should the price of plant-based meat alternatives decrease or additional plant-based protein options become available.

Sales of plant-based meat alternatives constitute some level of substitution for animal proteins, as well as an expansion of the protein market, Lusk explained. Using an economic model that links retail consumption to cattle production, he examined how a shift in demand toward plant-based meat alternatives—namely those created by processing a combination of ingredients such as soy, wheat, and pea, with novel additive ingredients such as heme (as opposed to less processed products such as tofu and tempeh)—could affect meat production (Lusk et al., 2022). Currently, he reported, these effects are fairly small. As an example, he observed that a 10 percent decrease in the price of plant-based meat alternatives is projected to create only a 0.15 percent decline in the number of cattle raised in the United States. As contributing factors he pointed to the small size of existing estimates across price elasticities of demand and the relatively inelastic nature of the U.S. cattle supply, which does not directly compete for land use with other forms of agriculture.

Lusk noted further that his statistics have focused on the U.S. economy, yet much of the growth in protein demand is likely to occur outside of the United States with respect to both animal- and plant-based protein sources. Thus, he argued, a larger discussion of proteins should consider the global dimension.

___________________

8 More information about the Monthly Meat Demand Monitor is available at https://agmanager.info/livestock-meat/meat-demand/monthly-meat-demand-monitor-survey-data (accessed September 30, 2022).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Image
FIGURE 2-3 Year-over-year change in retail sales of meat and meat alternatives.
SOURCE: Presented by Jayson Lusk on August 17, 2022.
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

THE ETHICS OF ALTERNATIVE PROTEINS: TECHNOLOGY, ANIMALS, AND SUSTAINABILITY

Garrett Broad, Rowan University, and Robert Chiles, The Pennsylvania State University, conduct a variety of qualitative and quantitative critical and empirical work examining food systems, alternative proteins, and social change. They discussed the social context for the debate about alternative protein sources, relevant ethical arenas of technology and animal food production, and perspectives of various communities engaged in this debate. Broad remarked that the field of ethics does not feature clear, objective answers; instead, it provides a framework for considering issues. Thus, he said, the lens of ethics can be applied to the passionate and often contentious debate around “fake” meat, as demonstrated by heated internet debates about plant-based meat alternatives. According to Broad, one such debate was spurred by a recent announcement that the Cracker Barrel restaurant chain would begin offering Impossible Sausage as a menu option. He added that some industry leaders and supporters contend that protein alternatives will replace all animal meat within the next 30 years. At the same time, he noted, numerous industry groups, activists, and advocacy communities are pushing back against novel plant-based meat alternatives. Broad contended that these debates are not solely about facts but instead are rooted in the values, ethics, and sociocultural context surrounding issues related to meat and alternative proteins. He clarified that the analysis he and Chiles would present focuses primarily on the debate in the United States.

Current Sustainability Crises

Chiles characterized the current historical moment in the United States—and the world at large—in terms of multiple sustainability crises and the challenges they present, asserting that the context of these challenges and their inherent opportunities and controversies should be considered in discussions of alternative proteins. He noted that data from FAO on global meat production indicated a four-fold increase between 1961 and 2018—from a total of approximately 71 million tons to more than 337 million tons. Chiles argued that although issues of animal rights and animal welfare are not currently included in the United Nations Sustainable Development Goals (SDGs), these issues are of critical importance to many stakeholders in the alternative protein debate. He stressed that billions of sentient vertebrate animals are raised, slaughtered, and hunted for food around the world each year, many of them experiencing significant pain and suffering. According to Chiles, the processes

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

of measuring, governing, financing, implementing, and auditing animal welfare and global food systems remain a monumental challenge, and the capacity to successfully produce, distribute, and adopt alternative proteins at scale could hypothetically reduce suffering and death among animals in the global food system.

In framing the ethics of the debate around alternative proteins, Chiles described two SDGs as particularly relevant: SDG 10, aimed at reducing inequality within and among countries, and SDG 16, aimed at prompting peaceful and inclusive societies for sustainable development and building effective, accountable, and inclusive institutions at all levels. According to Chiles, socioeconomic inequality is growing, while trust in institutions is declining. Since 1980, he observed, the vast majority of Americans have generated income that has trailed growth in per capita gross domestic product (GDP), whereas the incomes of the richest 0.01 percent have risen significantly faster than the GDP, by 420 percent (Leonhardt and Serkez, 2020). Chiles maintained that societal inequity is fueling polarization and distrust in the United States, with many people feeling that the “social contract” they entered into is broken. Decades ago, he remarked, a viable path for many featured a high school degree, employment at the same company for 30 years, and retirement with a pension, but this is no longer the case for many people; as a result, feelings of being left behind have grown. This dynamic, he asserted, is resulting in a “post-truth” society.

Chiles referenced the views of Francis Fukuyama, who argues that a post-truth society reflects a decline in the authority of institutions—including corporations, labor unions, the family, churches, and political parties—all of which have seen a decline in public trust over the past 40–50 years (Fukuyama, 2016). Fukuyama has identified resentment and fear as the greatest contributors to lack of trust among those who feel they are at risk of falling from the middle class into poverty, thus losing their social status. Chiles characterized the debate over alternative proteins as deeply embedded in a broader sense of angst about the future, which has been shaped by socioeconomic inequality, rapid social change, and declining trust in America’s institutions. He added that some people believe technology is a solution for meeting current challenges, whereas others see it as the root of the problem.

An Ethical Framework for the Alternative Protein Debate

Chiles presented a brief introduction to an ethical framework for considering the debate over the “right” way forward with respect to proteins. For decades, he said, the “trolley problem” has been used to illustrate

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

the tension between rights-based and utilitarian theories of ethics.9 He explained that utilitarian theory, based on prioritizing the greatest good for the greatest number, applies to the choice to divert the trolley, whereas the choice not to intervene is aligned with Kantian or rights-based theory, which argues that the ends do not justify the means.

Chiles argued that these basic ethical theories are highly relevant to intractable debates surrounding the future of the global food system. To illustrate how utilitarian theory applies, he pointed to advanced technologies that potentially can reduce costs and improve environmental outcomes for the urban majority while also disrupting the livelihoods and culture of the rural minority. Utilitarian arguments, he stated, tend to be invoked by advocates of food security, consumerists, the urban poor, and society as a whole. Rights-based arguments, on the other hand, tend to be invoked by advocates of food sovereignty, Indigenous peoples, family farmers, rural communities, and workers.

Chiles believes this ethical tension surrounds most public and academic discourse regarding the social impact of alternative protein sources. Both sides of the controversy rely on basic ontological assumptions in making their case, he noted, and forums such as this workshop can further inform these assumptions. He added that gathering evidence in support of arguments about which type of protein production system is most environmentally, politically, or economically sustainable will overshadow the core ethical disagreements involved. Ultimately, he stressed, no amount of research can determine whether the trolley should be diverted or, more importantly, what kind of world people want to live in. An example of this observation, Chiles cited, is farm loss, which began in the 1930s and has steadily continued to reduce the number of farms in the United States to 1860 levels (Plumer, 2012). Utilitarians would argue that this farm loss frees up labor to be used for more efficient purposes, he said, whereas the rights-based perspective would consider this a catastrophic social loss and highlight the destruction of rural communities. According to Chiles, competing ethical responses to inequality, rapid social change, and declining trust in institutions are shaping competing understandings about the future of alternative proteins.

___________________

9 The trolley problem poses a scenario in which a trolley is approaching five people on the tracks. If the trolley continues forward, the five people will be killed. However, a lever can be pulled that will divert the trolley to a track on which only one person is standing. Those considering the trolley problem must determine whether they would pull the lever to divert the trolley—resulting in one death—or allow it to continue its trajectory to kill five people. For more information, see https://www.britannica.com/topic/trolley-problem (accessed December 15, 2022).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Ethical Perspectives on Technology

Broad referenced the work of Sheila Jasanoff, a scholar of science and technology studies who advanced the idea of sociotechnical systems—the idea that technologies do not exist in isolation but are part of diverse assemblages of people, infrastructures, cultures, norms, laws, natural resources, and environments. Jasanoff defines sociotechnical imaginaries as “the collectively held, institutionally stabilized, and publicly performed visions of desirable futures.” Broad explained that around the world and across the United States, people hold differing sociotechnical imaginaries, or visions of desirable futures (Jasanoff and Kim, 2015).

Broad went on to explain the two poles of sociotechnical imaginaries identified by Charles Mann (2018): “wizards,” who believe that science and technology, when properly applied, provide a production pathway out of dilemmas, and “prophets,” who believe in natural limits that are transgressed by humans at their peril. The wizard perspective is a utilitarian view that by being smart and producing more, everyone can win, elaborated Broad, whereas prophets believe that people can avoid losing by conserving and obeying rules. He added that wizards believe in industrial-scale and centralized, technology-focused, utilitarian solutions, whereas prophets want technology to be decentralized and limited. Prophets are culturally focused, he observed, believing that solutions should emerge from grassroots communities, from education, and from a foundation of rights-based appeals about what is right for food and for society.

Ethical Perspectives on Animal Foods

Broad went on to identify the relationship among humans, animals, and animal food production as another ethical arena pertaining to animal-sourced proteins. He referenced a large body of scholarship on the symbolic meanings of meat from both historical and evolutionary perspectives (Fairlie, 2010; Fiddes, 1992; Graça et al., 2015; Joy, 2020). Some people believe, Broad explained, that meat is and should continue to be an important part of society, while others critique an unquestioned ideology of meat consumption and attachment. Broad pointed to the term “carnism,” used in the psychological literature and within activist communities to refer to a commitment to the belief that meat consumption is natural, normal, and necessary. He observed that the concept of meat attachment can be used to categorize viewpoints on meat consumption as satisfying the “4 N’s” —that is, natural, normal, necessary, and nice (Graça et al., 2015).

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

An Ethical Matrix for Alternative Protein

Broad next presented a matrix that can be used to illustrate ethical beliefs among those engaged in debate about protein alternatives. In this matrix, the pole of techno-optimism (i.e., wizard and utilitarian) to techno-skepticism (i.e., prophet and rights-based) constitutes the vertical axis, while the level of meat attachment (from high to low) forms the horizontal axis (Figure 2-4). According to Broad, this matrix can be used to plot four ideal types representing the key communities engaged in the alternative protein debate: (1) high-tech vegans, (2) ecomodernists, (3) plant-based foodies, and (4) carnivore traditionalists. He emphasized that this framework of poles and ideal types is useful for purposes of analysis but that most people do not fit squarely into one type.

The techno-optimism ideal types include high-tech vegans and ecomodernists, Broad continued. High-tech vegans, he elaborated, have high levels of techno-optimism and low levels of meat attachment. They would prefer that all people would become ethical vegans, but they recognize the power meat attachment holds for many people; thus, they believe the way forward is to make meat without animals. High-tech vegans include

Image
FIGURE 2-4 Matrix of ethical beliefs about protein alternatives.
SOURCE: Presented by Garrett Broad and Robert Chiles on August 17, 2022.
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

mission-driven startups and some animal rights and animal welfare communities. Broad cited examples of high-tech vegan ideology, including an opinion piece by Ezra Klein calling for a moonshot for meatless meat, and the Good Food Institute, a major advocacy and research organization working to accelerate the alternative protein field (Klein, 2021).

Moving to ecomodernists, Broad explained that they have high levels of techno-optimism but also high levels of meat attachment. They believe that global demands for protein are increasing and that this demand should be met with innovative proteins in all forms, from conventional meat to alternatives. Rather than calling for meat consumption to end, ecomodernists advocate for additional protein options. Broad gave the example of Tyson Foods, which markets itself as a protein company and offers a plant-based product line in addition to its animal-based products. Ecomodernists, he added, include multinational companies and technology research and development advocates (Blaustein-Rejto et al., 2021; Lusk, 2016; Smith et al., 2021).

The techno-skepticism ideal types include plant-based foodies and carnivore traditionalists, Broad continued. Plant-based foodies, he elaborated, feature the low meat attachment of high-tech vegans and believe that meat consumption should be reduced, but they do not see technology as the solution. Instead, they advocate for grassroots, community-based solutions—for example, eating more natural plant-based protein sources, such as beans, and sourcing products locally. Plant-based foodies include some animal rights advocates and social justice–oriented advocates for reducing meat. As examples, Broad cited food journalist Mark Bittman, who calls for solutions other than “fake” meat, and Breeze Harper, a Black feminist animal rights activist who identifies the problems with what she describes as food tech startups framed through a White neoliberal-capitalist masculinist logic.

Finally, Broad described carnivore traditionalists as techno-skeptics with a high level of meat attachment. They believe that meat consumption is not inherently problematic, but industrial methods used for factory farming and laboratory-created meat should be replaced by more environmentally friendly methods. Broad emphasized that carnivore traditionalists believe humans should eat more beef, not less, and it should come from what they term “regeneratively raised livestock.” This ideal type, Broad explained, comprises local ranchers, regenerative meat advocates, and people who prefer low-tech solutions and are critical of companies such as Impossible Foods, which they view as too corporate and techno-focused.

Food Technology Justice

Broad stated that he and Chiles see limitations to each of the above ideal types and cautioned that adhering strictly to the boundaries of these ideals can lead to missed opportunities for collaboration and

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

consensus-driven solutions in a landscape of significant challenges. Chiles mentioned a number of groups working toward meat alternatives, including Shojinmeat Project in Japan, a nonprofit organization using citizen science to develop open-source clean meat; the Cultivated Meat Modeling Consortium; Meat Our Future, a South African public–private partnership; the Plant Based Foods Institute; and the Transfarmation Project, which is working to help farmers transition industrial animal-agriculture operations to plant-focused farms raising crops for human consumption. Chiles argued that moral imagination—which entails creative thinking to envision moral alternatives others do not see—can enable momentum beyond the polarization and controversy of the debate about alternative proteins. Broad asserted that blending principles of technology with principles of justice and sustainability can lead to the development of new solutions for addressing current crises.

DISCUSSION

The discussion following the presentations summarized above focused on modeling multiple relevant factors, the role of policy in farming income, carbon farming and rewilding of land, social and economic sustainability and quality of life, and implications for farm laborers.

Modeling Multiple Relevant Factors

Fukagawa asked whether the various dimensions of the alternative protein issue—including health, nutrition, economic, social, and environmental factors—should be modeled simultaneously to better understand the trade-offs involved in establishing a nutrient-adequate, healthy diet. Conrad replied that this topic is being debated in the field. He believes these numerous factors should be modeled together. He pointed out, however, that investigating multiple indicators of environmental, social, and other domains of sustainability individually is currently challenging, and determining how to consider indicators in multiple domains simultaneously—for example, comparing environmental measures such as greenhouse gas emissions with measures of such social sustainability issues as forced labor—remains a goal. Conrad remarked that certain indexes for this purpose have been proposed, but they carry the risk of inflating error estimates beyond acceptable levels.

Role of Policy in Farming Income

In response to a question about maintaining farmers’ income while reducing the production of animal-sourced protein, Lusk replied that if a

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

significant shift from animal-based proteins toward plant-based meat alternative were to occur, farming could become less profitable. Such a shift would be a consequence of technology development or shifts in demand, and it would involve winners and losers, he remarked. He stressed that public policy could ease this shift, using transition planning to create opportunities. He noted that numerous farm policies are in place that incentivize certain types of production, but traditionally, livestock and animal-based protein have not been primary beneficiaries of these policies; rather, incentives have influenced primarily corn and soybean crops. Lusk remarked that farm policy is extraordinarily complex, with some policies being designed to reduce prices and so make food more affordable, and others to raise the prices of certain commodities, making them more expensive than they would otherwise be. These policies coexist in complex ways that vary depending on the commodity, he explained. Lusk suggested that government policy is a potential lever for affecting plant and animal agriculture to reduce the production of animal-sourced protein. He added, however, that farmers are driven predominantly to grow certain crops at certain scales based on their ability to efficiently turn sunlight energy and nutrients in the soil into a form of energy and protein that is easily storable and transportable. Thus, he suggested, policy could have a small, though not negligible, effect on this issue.

Carbon Farming and Rewilding of Land

Fukagawa asked about the potential role of offering payments to farmers to rewild their land (similar to how land banking has been handled in the past), as well as providing credits for carbon sequestration. Lusk remarked that private entities—such as nongovernmental organizations working to conserve land or keep farmland in production—are purchasing land for rewilding or for other purposes they deem beneficial. He emphasized that all farmland is owned, and in some cases, as in the Midwest, quality farmland can be valued at $10,000 per acre or more. Thus, he said, a privately owned farm can equate to millions of dollars in assets, and substantial economic incentives are therefore required to induce farmers to sell their land. The value of U.S. farmland assets in a given year is in the hundreds of billions of dollars, he added.

Broad remarked that advocates for plant-based or cell-cultured meat often argue that shifting away from animal-sourced protein would make land available for rewilding. However, land formerly used for livestock is not guaranteed to be allocated for rewilding and instead could be used for shopping malls or other projects that are worse for climate change than agricultural use. Thus, he argued, technological advances in food production alone will not solve these issues, nor is it safe to assume that technological change will automatically lead to positive social outcomes.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

Rather, collaborative stakeholder engagement processes are needed to develop social- and governance-oriented solutions that can bring the idea of rewilding land to fruition. Chiles commented that the issue of land use has ramifications far into the future and extends beyond the United States to a global market, including such areas as Brazil and sub-Saharan Africa.

Social and Economic Sustainability and Quality of Life

In response to a question about how sustainability indicators relate to social and economic sustainability and quality-of-life benefits, Conrad stated that current goals include identifying those links, determining how to measure them, and developing the training needed to address remaining unknowns in this area. Lusk remarked that much of the agricultural economy is involved in animal production, and a change from the status quo could be costly for some individuals. He pointed out that farmers may define sustainability as earning enough money to continue farming each year; thus, economic incentives must be considered. As an economist, he added, he views prosperity as a component of economic growth, which involves increasing the productivity of agriculture through continued innovation and improvement. From the standpoint of productivity growth and continual improvement, he asserted, preservation of the status quo is not the optimal scenario. He stressed that technology and change are inevitable and will result in winners and losers, but increasing protein productivity using fewer resources will be a long-term net win for society.

Broad argued that the quality of life of the animals raised in food production should be considered in the context of quality-of-life benefits. He emphasized that although the vegan diet does not eliminate animal suffering—such as animal deaths resulting from pest management and fuel production—a food system that relies heavily on animal sources for protein has substantial animal welfare implications. And he stressed that the weight given to animal welfare in calculating environmental or social sustainability shapes thinking around the best path forward. Broad commented that animal welfare is a central fault line in the protein debate, yet it tends to be overshadowed by topics related to environmental and economic implications. Chiles added that competing cultural and ethical tensions unrelated to alternative protein play a role in sustainability. For instance, the droughts and wildfires of recent years present challenges to farmers that are wholly unrelated to alternative proteins and cell-cultured meat.

Implications for Farm Laborers

Fukagawa asked about potential implications of a shift toward alternative protein sources for laborers in the agriculture and food system. Conrad

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

referenced research on forced labor in the fruit and vegetable system and a conclusion that healthy eating and other measures of sustainability involve social considerations and environmental trade-offs (Blackstone et al., 2021). He predicted that simultaneously maximizing all domains of sustainability may not be possible, in which case values inform the circumstances and considerations on which people are willing to compromise. Chiles drew a parallel between agriculture and the coal industry. In West Virginia and Kentucky, he observed—areas heavily involved in coal production—a viewpoint that environmental regulations destroy the job market is common. He pointed out, however, that automation, not environmental advocacy or wildlife conservancy, is responsible for eliminating jobs in the coal industry. Similarly, he noted, automation has been eliminating agricultural jobs for hundreds of years, and artificial intelligence is currently being used to further automate the meat industry. According to Chiles, this dynamic underscores that the social and environmental implications of agricultural changes extend beyond the issue of alternative proteins.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×

This page intentionally left blank.

Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 3
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 4
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 5
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 6
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 7
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 8
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 9
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 10
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 11
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 12
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 13
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 14
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 15
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 16
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 17
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 18
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 19
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 20
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 21
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 22
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 23
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 24
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 25
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 26
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 27
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 28
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 29
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 30
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 31
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 32
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 33
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 34
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 35
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 36
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 37
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 38
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 39
Suggested Citation:"2 Current Protein Challenges." National Academies of Sciences, Engineering, and Medicine. 2023. Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/26923.
×
Page 40
Next: 3 Implications for the Industry, Consumers, and Regulators »
Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop Get This Book
×
 Alternative Protein Sources: Balancing Food Innovation, Sustainability, Nutrition, and Health: Proceedings of a Workshop
Buy Paperback | $24.00 Buy Ebook | $19.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Alternative protein sources, which can be derived from plant and animal cells or created by precision fermentation, can have health, environmental, socio-economic, and ethical impacts. With a variety of types of alternative proteins being developed and available on the market, consumers, regulatory agencies, manufacturers, and researchers are faced with many different considerations. The National Academies Food Forum hosted a workshop that took a multi-sector approach to explore the state of the science on alternative protein sources as they relate to issues around diet quality, nutrition, and sustainability. The workshop also examined how alternative protein food processing innovations can be balanced in a way that optimizes nutritional content, affordability, and accessibility. This Proceedings of a Workshop summarizes the discussions held during the workshop.

READ FREE ONLINE

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!