Forty-four overweight subjects with type 2 diabetes mellitus were enrolled in a randomized, placebo-controlled, double blind trial of pharmacologic induction of weight loss. All subjects received intensive nutrition counseling, an exercise prescription, instruction on behavioral management, and were randomly assigned to fenfluramine 20mg three times daily and phentermine 37.5mg daily (n=23) or dual placebos (n=21). Drug therapy continued until September 1997 when fenfluramine was withdrawn from the US market. Dietary intake was assessed by administration of a food frequency questionnaire (Block 95) at baseline, 2, 6, and 12 months. Mean +/- SEM baseline data for the placebo group and the active drug group, respectively, were: Weight (kg) 106 +/- 4, 108 +/- 4; kilocalories 2991 +/- 445, 3053 +/- 482; carbohydrate (%) 36.9 +/- 1.5, 40.2 +/- 2.5; protein (%) 15.8 +/- 1.9, 14.8 +/- 1.1; fat (%) 47.8 +/- 2.6, 44.7 +/- 2.5. Changes from baseline (* placebo vs. active, p< .05):Weight (kg)KcalCHOPROFAT2 Months(% energy)(% energy)(% energy)Placebo (n=18)-1.6+/-0.5-482+/-2503.0+/-1.30.1+/-0.8-3.4+/-1.6Active (n=21)-7.9+/-1.2 * -491+/-1833.1+/-1.31.0+/-0.8-4.2+/-1.56 MonthsPlacebo (n=13)-2.7+/-1.4-636+/-2415.2+/-1.70.6+/-0.8-6.2+/-1.6Active (n=13)-9.6+/-1.5 * -284+/-2774.6+/-2.8-0.3+/-0.7-4.5+/-2.612 MonthsPlacebo (n=8)-2.5+/-2.5-670+/-3104.2+/-2.1-0.1+/-1.4-4.8+/-2.0Active (n=8)-8.1+/-1.6-605+/-277-3.4+/-5.14.5+/-3.3-4.6+/-4.5 Body weight was reduced at all time points for both groups, but was significantly reduced in the drug treatment groups at 2 and 6 months. Although a reduction in reported total energy intake was observed in both groups, no significant difference was detectable between groups. The reported change in intake was accounted for primarily by a reduction in fat intake.