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Exercise has well-recognized health benefits, including reduction in risk factors for cardiovascular disease and type 2 diabetes. However, the extent to which exercise influences energy regulation and facilitates a reduction in body fat is less clear. This review summarizes published studies on the effects of different amounts of exercise on body fatness, energy intake, and food preferences in humans. The results show consistent effects of exercise on body fatness in the absence of prescribed dietary change, with a progressive loss of body fat associated with higher exercise energy expenditures in both men and women. In part, these effects appear to be mediated by a spontaneous reduction in hunger associated with participation in exercise. Insufficient data are available on whether there are changes in food preferences and taste perception that influence energy balance through macronutrient selection, so further studies in this area are needed. doi: 10.1301/nr.2007.jan. 1-19 Key words: body composition, energy intake, exercise, food palatability, macronutrient

There is considerable uncertainty over whether any one dietary pattern broadly facilitates weight loss or maintenance of weight loss, and current dietary guidelines recommend a spectrum of dietary composition for the general population. However, emerging evidence suggests that specific dietary compositions may work better for identifiable groups of overweight/ obese individuals based on their individual metabolic status. In particular, characteristics of insulin dynamics, such as insulin sensitivity or insulin secretion status, may interact with diets that vary in macronutrient composition to influence the weight loss achieved with a hypocaloric diet. Key words: dietary composition, insulin secretion, insulin sensitivity, weight loss

Obesity, cardiovascular disease, and type 2 diabetes mellitus are now prevalent among adults living in developing countries; these chronic diseases affect socioeconomically disadvantaged adults living in impoverished families with undernourished children. This review summarizes data from Brazil--a developing country undergoing the nutrition transition--suggesting an association between childhood undernutrition and obesity and chronic degenerative disease. Potential mechanisms for the association include long-term effects of childhood undernutrition on energy expenditure, fat oxidation, regulation of food intake, susceptibility to the effects of high-fat diets, and altered insulin sensitivity. The combination of childhood undernutrition and adult chronic degenerative disease results in enormous social and economic burdens for developing countries. Further research is urgently needed to examine the effect of childhood undernutrition on risk of obesity and chronic degenerative diseases; one goal of such research would be to determine and provide low-cost methods for prevention and treatment. Key Words: undernutrition, stunting, obesity, diabetes, hypertension

Recommendations for increased consumption of protein are among the most common approaches of popular or fad diets. This review summarizes the effects of dietary protein on satiety, energy intake, thermogenesis, and weight loss, as well as its effect on a variety of health outcomes in adults. In short-term studies, dietary protein modulates energy intake via the sensation of satiety and increases total energy expenditure by increasing the thermic effect of feeding. Whereas these effects did not contribute to weight and fat loss in those studies in which energy intake was fixed, one ad libitum study does suggest that a high-protein diet results in a greater decrease in energy intake, and therefore greater weight and fat loss. In terms of safety, there is little long-term information on the health effects of high-protein diets. From the available data, however, it is evident that the consumption of protein greater than two to three times the U.S. Recommended Daily Allowance contributes to urinary calcium loss and may, in the long term, predispose to bone loss. Caution with these diets is recommended in those individuals who may be predisposed to nephrolithiasis or kidney disease, and particularly in those with diabetes mellitus. Key Words: dietary protein, energy intake, thermogenesis, weight loss, high-protein diet, urinary calcium loss, bone loss

Research has been conducted on the high-glycemic index carbohydrates. Results suggest that the consumption of these carbohydrates may increase hunger and promote overeating.

Research presented concerns the physiological aspects of unintentional weight loss in aging adults. Issues discussed concern biobehavioral and social factors that may impair the metabolism and regulation of food intake.

The effects of fat-modified foods or low-fat diets will only have a slight effect on obesity. Fat replacement or reductions are only one part of a broader scheme that must involve lifestyle modification. Consumers who use fat-modified foods consistently over many years may witness a impact toward recommended dietary goals.

Genetic abnormalities found in both animal and human research may contribute to obesity. Researchers have identified three obesity genes in mouse models, the agouti protein, the Ob protein, and the fat gene. In contrast, genetic evidence in human obesity seems to be much more complex. Possible contributing factors to total body fat include DNA variations of apolipoproteins, uncoupling protein, adrenergic receptors, and lipoprotein lipase. Five human genes may be linked to abdominal fat accumulations. Fat deposits in certain parts of the body has also been linked to DNA polymorphisms, such those for insulin, apolipoproteins, and adrenergic receptors.

Controversy continues on the role of energy expenditure in regulating energy in human beings. It has been seen that energy expenditure contributes to energy regulation in normal individuals and also to the deregulation of energy balance that distinguishes obesity. An apparent equilibration between physical activity and body fat content due to a direct influence of physical activity on the metabolic determinants of energy balance is also suggested.

Caloric restriction (CR) is a strategy that attenuates aging in multiple nonhuman species. The Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE) trials are part of a research program aiming to test the effects of CR on aging and longevity biomarkers in humans. Building on CALERIE phase 1, CALERIE phase 2 (CALERIE 2) was the largest study to date to assess sustained CR in healthy humans without obesity. In a 24-month randomized controlled trial comprising 218 participants at baseline, CALERIE 2 showed that moderate CR, 11.9% on average, induced improvements in aging-related biomarkers without adversely affecting psychological or behavioral outcomes. The objectives of this report are to summarize and review the highlights of CALERIE 2 and report previously unpublished results on eating disorder symptoms and cognitive function. This article specifically summarizes the physiological, psychological, aging, behavioral, and safety results of the trial. Also provided are research directions beyond CALERIE 2 that highlight important opportunities to investigate the role of CR in aging, longevity, and health span in humans. [ABSTRACT FROM AUTHOR]

Summarizes the effects of dietary energy density (ED) on energy regulation, in particular when ED is changed by manipulating different dietary constituents such as fat, fat plus fiber, water, or type of sweetener. Definition of dietary ED; Roles of ED in energy regulation; Historic and epidemiologic data on dietary ED; Effects of ED on hunger and satiety; Effects of ED on energy intake and body weight.