Effect of amphetamine on human macronutrient intake

Six male subjects participated in a 15-day residential study examining the effects of amphetamine on macronutrient intake. During the first 11 days, carbohydrate intake was manipulated by providing lunch meals high (155 g) or low (25 g) in carbohydrate. Subjects received oral d-amphetamine (5, 10 mg/70 kg, BID) or placebo. Total daily caloric intake was similar under both lunch conditions (∼ 3400 Kcal), but carbohydrate contributed more energy under the high-carbohydrate condition. Both doses of amphetamine decreased total caloric intake to ∼ 2600 Kcal, by decreasing the number of eating bouts, without affecting macronutrient selection. During the last four days subjects received a higher daily dose of amphetamine (30 mg/70 kg in four doses) or placebo, and were allowed to self-select lunch. Although 30 mg amphetamine decreased intake of all macronutrients, the relative contribution of carbohydrate to total caloric intake was increased from 54% to 62%, while the contribution of fat was decreased from 32% to 26% and the contribution of protein was decreased from 14% to 12%. Thus, at a high dose, amphetamine altered the relative contribution of specific macronutrients to total caloric intake.