Diet and Health Implications for Reducing Chronic Disease Risk (1989) / Chapter Skim
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21 Obesity and Eating Disorders
21 Obesity and Eating Disorders
Pages 563-592
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From page 563... ...
In recent years, fat distribution has also been included. It is now clear that two important factors associated with the risk of developing sev eral chronic diseases are total body fat (most often estimated from ratios of body weight to height)
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From page 564... ...
reanalyzed the Build and Blood Pressure Study of 1979 (Society of Actuaries, 1980a,b) and showed that the BM!
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From page 565... ...
The size of this sample and the 5-year follow'up provide a useful basis on which to determine relationships between weight and risks for cardiovascular diseases, hypertension, and diabetes (Waaler, 19841. Pat Distribution Fat distribution can be estimated by skinfolds, by waist-to-hip circumference ratios, or by such sophisticated techniques as ultrasound, computed tomography, or magnetic resonance imaging.
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From page 566... ...
Fat Cell Size and Number The number of fat cells can be estimated from measurements of total body fat and the average size of a fat cell. A reliable estimate of the total number of fat cells should be based on the average size of fat cells from more than one location, because fat cells differ in size from one region to another.
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From page 567... ...
CAUSES OF OBESITY: INCREASED ENERGY INTAKE OR DECREASED ENERGY EXPENDITURE? Energy Intake There is little question that extreme changes in food intake produce corresponding changes in body weight (Bray, 1976; Forbes, 1987; Garrow, 1978~.
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From page 568... ...
Thus, increases in adiposity in some cases must reflect decreases in energy expenditure or changing metabolic efficiency. Metabolic Efficiency Animal studies provide clear evidence that increased energy intake is not required to induce obesity (Bray and York, 1971, 1979~.
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From page 569... ...
Retrospective Life Insurance Studies Applicants for individual life insurance policies usually undergo a medical examination. In the Build and Blood Pressure Study of 1979 (Society of Actuaries, 1980a,b)
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From page 570... ...
Weight gain was associated with an increase in serum cholesterol, blood pressure, uric acid, and blood glucose (Ashley and Kannel, 1974~. Overweight was also associated with an increased risk of sudden death, presumably from CHD; however, the exact cause is unknown.
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From page 571... ...
These findings are similar to the increases observed both in the Build and Blood Pressure Study of 1979 (Society of Actuaries, 1980a,b) and in the Framingham study (Kanne!
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From page 572... ...
A reduction in blood pressure usually follows weight loss. During periods of caloric deprivation, such as World War ~ or World War IT, hypertension was almost nonexistent.
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How' ever, weight reduction was observed to produce a significant reduction in blood pressure in more than half of the hypertensive patients studied by MacMahon et al.
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and Newburgh and Conn (1939) , studies have consistently shown that weight loss in obese subjects could improve glucose tolerance and that weight gain could worsen it.
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found that bile was more highly saturated with cholesterol in 23 obese subjects than in the 23 nonobese con' trots. The hepatic secretion of cholesterol was higher in 11 subjects before weight loss than 575 afterward, but neither phospholipids nor bile salt secretion changed.
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From page 576... ...
Furthermore, there is evidence that repeated cycles of weight loss and regain alone may enhance metabolic efficiency in animals (Browned et al., 19861. Given the high prevalence of dieting, it iS surprising that the long-term consequences of weight loss and weight gain are not well understood, especially in relation to the normal aging process, and that even less is known about the health consequences of repeated cycles of dieting.
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From page 577... ...
Eighty percent developed diabetes; one-half of these cases were severe. Weight loss may be accompained by changes in several chronic disease risk factors, e.g., lowered blood pressure or lowered triglycerides.
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From page 578... ...
Framingham Study At the fourth biennial examination in the Framingham study, several measures of regional fat distribution were taken, including waist, but not hip, circumference, plus measurements of subscapular, tricep, abdominal, and quadricep skinfolds. The 22-year incidence of CHD was significantly related to thickness of the subscapular skinfold.
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From page 579... ...
Extensive alterations in pulmonary function are observed primarily in massively obese subjects or in obese people with some other respiratory or cardiovascular problem. In a careful study of 29 obese women and 14 obese men, there was a progressive decrease in expiratory reserve volume as the weight-to-height (kg/cm)
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From page 580... ...
Infants born to heavy women weigh more than the offspring of light women.-There is also a direct relationship between placental weight and prepregnancy body weight. At the age of 7, approximately 50% of the incremental weight gain can be accounted for by the differences in placental weight at birth and the remaining 50% is attribut
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From page 581... ...
(The syndrome of po~ycystic ovaries, however, is associated with obesity, as discussed in the next section, an] is not corrected by weight loss.)
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There is little question that sex hormones regulate certain aspects of food ingestion, fat distribution, and the redistribution of fat during pregnancy and lactation. In animals, much of the effect of the sex hormones on the distribution of fat is believed tO be mediated through the action of the hormones on adipose tissue LPL activity.
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From page 583... ...
. Anorexia nervosa is characterized by extreme weight loss, body-image disturbance, and an intense fear of becoming obese.
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From page 584... ...
Central to this weight phobia is a preoccu' pation with maintaining a low subpubertal body weight and avoiding any weight gain. Low body weight control may be sustained mainly by carbohydrate and At avoidance a fonn of starvation unique to anorexia nervosa (Crisp, 1977; Garfinke} and Gamer, 1982~.
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From page 585... ...
It has been postulated that there is a genetic component that contributes to the risk of developing insulin resistance. In general, weight loss in obese subjects could improve glucose tolerance and weight gain could worsen it.
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From page 586... ...
Weight gain or gain-and-Ioss cycles in adults may carry greater risks for chronic disease than does stable body weight. DIRECTIONS FOR RESEARCH · It is now recognized that fat distribution, particularly the fat deposition in the abdominal and probably the intraabdominal region, is an important determinant of health risk; however, several important questions remain to be answered: Are intra- and extraabdominal subcutaneous fat equally important?
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From page 587... ...
1985. Is the relationship between blood pressure and cardiovascular risk dependent on body mass index7 Am.
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1986. The pattern of subcutaneous fat distribution in middle-aged men and the risk of coronary heart disease: the Paris Prospective Study.
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1982. Relation of body fat distribution to metabolic complications of obesity.
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1980. Body weight change in relation to incidence of ischemic heart disease and change in risk factors for ischemic heart disease.
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1978. Effect of weight loss without salt restriction on the reduction of blood pressure in overweight hypertensive patients.
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From page 592... ...
1976. Delayed pituitary hormone response to LRF and TRF in patier~ts with anorexia nervosa and with secondary amenorrhea associated with simple weight loss.
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