ENERGY-EXPENDITURE, BODY-COMPOSITION, AND GLUCOSE-METABOLISM IN LEAN AND OBESE RHESUS-MONKEYS TREATED WITH EPHEDRINE AND CAFFEINE

The administration of ephedrine and caffeine (E+C) has been proposed t o promote weight loss by increasing energy expenditure and decreasing food intake. We tested this hypothesis in six lean (4-9% body fat) and six mildly to moderately obese (13-44% body fat) monkeys studied duri ng a 7-wk control period, an 8-wk drug treatment period, and a 7-wk pl acebo period. During the drug treatment period, the monkeys were given ephedrine (6 mg) and caffeine (50 mg) orally three times per day. At the end of each period, a glucose tolerance test was performed, energy expenditure was measured, and body composition was determined. Treatm ent with E+C resulted in a decrease in body weight in the obese animal s (P = 0.06). This loss in weight was primarily the result of a 19% re duction in body fat. Drug treatment also resulted in a decrease in bod y fat in the lean group (P = 0.05). Food intake was reduced by E+C onl y in the obese group (P <0.05). Nighttime energy expenditure was incre ased by 21% (P < 0.03) in the obese group and 24% (P <0.01) in the lea n group with E+C treatment. Twenty-four-hour energy expenditure was hi gher in both groups during drug treatment. E+C did not produce systema tic changes in glucoregulatory variables, whereas plasma leptin concen trations decreased in both groups with drug treatment. Overall, these results show that E+C treatment can promote weight loss through an inc rease in energy expenditure, or in some individuals, a combination of an increase in energy expenditure and a decrease in food intake.