Obesity Epidemiology

280 EPIDEMIOLOGIC STUDIES OF DETERMINANTS OF OBESITYsignificantly more weight (8.8 vs. 5.1 kg) and fat (7.6 vs. 4.3 kg) than those on the lowproteindiet (12% energy from protein).Overall, there is some evidence that high-protein diets enhance short-term weight lossas compared with lower-protein diets. Possible mechanisms include increased satiety anddecreased subsequent energy intake, increased thermogenesis, and reduced GL. 33 However,larger and longer-term studies are clearly needed to draw firm conclusions about therole of protein in weight control.Foods and Food GroupsRecent studies have examined the relationship between consumption of specific foods oroverall dietary patterns and body fatness. Such analyses are of value for identifying dietarydeterminants of obesity that can be useful in making practical dietary recommendations.Whole Grains and FiberWhole-grain products (e.g., whole wheat breads, brown rice, oats, and barley) usually havelower GI values and are richer in fiber, antioxidant vitamins, magnesium, and phytochemicalsthan are refined-grain products, which lose substantial amounts of dietary fiberand other beneficial nutrients during processing. Several studies have found an inverseassociation between consumption of whole-grain foods and risk of type 2 diabetes andcardiovascular disease. 22 However, there are few epidemiologic studies on whole-grainfoods and risk of obesity. At 7-year follow-up, the Coronary Artery Risk Developmentin Young Adults (CARDIA) study showed an inverse relationship between whole-grainintake and BMI, but no association between whole-grain intake and waist-to-hip ratio. 34During 12 years of follow-up in the Nurses’ Health Study (NHS), Liu et al. 35 examinedthe relationship between changes in intakes of dietary fiber and whole- or refinedgrainproducts and weight gain. Increased consumption of whole grains was associatedwith a lower mean 4-year weight gain (1.58 kg in the lowest quintile and 1.07 kg in thehighest quintile; P for trend