The influence of dietary fiber on energy regulation remains controversial. This review summarizes published studies on the effects of dietary fiber on hunger, satiety, energy intake, and body composition in healthy individuals. Under conditions of fixed energy intake, the majority of studies indicate that an increase in either soluble or insoluble fiber intake increases postmeal satiety and decreases subsequent hunger. When energy intake is ad libitum, mean values for published studies indicate that consumption of an additional 14 g/day fiber for >2 days is associated with a 10% decrease in energy intake and body weight loss of 1.9 kg over 3.8 months. Furthermore, obese individuals may exhibit a greater suppression of energy intake and body weight loss (mean energy intake in all studies was reduced to 82% by higher fiber intake in overweight/obese people versus 94% in lean people; body weight loss was 2.4 kg versus 0.8 kg). These amounts are very similar to the mean changes in energy intake and body weight changes observed when dietary fat content is lowered from 38% to 24% of energy intake in controlled studies of nonobese and obese subjects. The observed changes in energy intake and body weight occur both when the fiber is from naturally high‐fiber foods and when it is from a fiber supplement. In view of the fact that mean dietary fiber intake in the United States is currently only 15 g/day (i.e., approximately half the American Heart Association recommendation of 25–30 g/day), efforts to increase dietary fiber in individuals consuming >25 g/day may help to decrease the currently high national prevalence of obesity.

OBJECTIVE -The aim of this study was to examine the relation between carbohydraterelated dietary factors, insulin resistance, and the prevalence of the metabolic syndrome in the Framingham Offspring Cohort.RESEARCH DESIGN AND METHODS -We examined cross-sectional associations between carbohydrate-related dietary factors, insulin resistance, and the prevalence of the metabolic syndrome in 2,834 subjects at the fifth examination (1991)(1992)(1993)(1994)(1995) of the Framingham Offspring Study. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated using the following formula (fasting plasma insulin ϫ plasma glucose)/22.5. The metabolic syndrome was defined using the National Cholesterol Education Program criteria.RESULTS -After adjustment for potential confounding variables, intakes of total dietary fiber, cereal fiber, fruit fiber, and whole grains were inversely associated, whereas glycemic index and glycemic load were positively associated with HOMA-IR. The prevalence of the metabolic syndrome was significantly lower among those in the highest quintile of cereal fiber (odds ratio [OR] 0.62; 95% CI 0.45-0.86) and whole-grain (0.67; 0.48 -0.91) intakes relative to those in the lowest quintile category after adjustment for confounding lifestyle and dietary factors. Conversely, the prevalence of the metabolic syndrome was significantly higher among individuals in the highest relative to the lowest quintile category of glycemic index (1.41; 1.04 -1.91). Total carbohydrate, dietary fiber, fruit fiber, vegetable fiber, legume fiber, glycemic load, and refined grain intakes were not associated with prevalence of the metabolic syndrome.CONCLUSIONS -Whole-grain intake, largely attributed to the cereal fiber, is inversely associated with HOMA-IR and a lower prevalence of the metabolic syndrome. Dietary glycemic index is positively associated with HOMA-IR and prevalence of the metabolic syndrome. Given that both a high cereal fiber content and lower glycemic index are attributes of whole-grain foods, recommendation to increase whole-grain intake may reduce the risk of developing the metabolic syndrome. Diabetes Care 27:538 -546, 2004T ype 2 diabetes is a major cause of morbidity and mortality in the U.S.(1), and the prevalence of this disease continues to rise (2). One subgroup of the population at increased risk of developing type 2 diabetes are individuals with the "metabolic syndrome," a condition characterized by disturbed glucose and insulin metabolism, central obesity, mild dyslipidemia, and hypertension (3). Recent estimates indicate that the metabolic syndrome is highly prevalent in the U.S., with an estimated 24% of the adult population affected (4). The etiology of this syndrome is largely unknown, but presumably represents a complex interaction between genetic, metabolic, and environmental factors, including diet (5-7). Whereas aspects of diet have been linked to individual metabolic features of the syndrome (8,9), the role of diet in the etiology of the metabolic syndrome is poorly understoo...

Sustained CR is feasible in nonobese humans. The effects of the achieved CR on correlates of human survival and disease risk factors suggest potential benefits for aging-related outcomes that could be elucidated by further human studies.

The literature describing vitamin D content of fat tissue is extremely limited. We conducted a pilot study that measured the concentrations of vitamin D(3) in the fat tissue and serum of obese adults. These measurements were performed using a new liquid chromatography mass spectrometry (LC/MS) method. The objectives of this study were: to measure and report the vitamin D(3) concentration in serum and subcutaneous fat samples from obese individuals and to examine the association of vitamin D(3) in fat with vitamin D(3) in serum. This cross-sectional study was conducted in 17 obese men and women who were scheduled to undergo gastric bypass surgery. The mean vitamin D(3) concentration in subjects' subcutaneous fat tissue samples was 102.8 +/- 42.0 nmol/kg. The mean vitamin D(3) concentration in serum was 7.78 +/- 3.99 nmol/l. Vitamin D(3) concentrations of fat tissue and serum were positively correlated (r = 0.68, P = 0.003). Consistent with previous findings in obese subjects, subjects in this study had suboptimal vitamin D status as demonstrated by a mean 25-hydroxyvitamin D concentration of 43.3 +/- 15.4 nmol/l. In conclusion, fat tissue vitamin D(3) can be measured by LC/MS and is detectable in obese subjects with suboptimal vitamin D status. Compatible with the long-standing concept that fat tissue is a storage site for vitamin D, fat tissue and serum vitamin D(3) concentrations were positively correlated.