Effect of a high-protein, energy-restricted diet on weight loss and energy expenditure after weight stabilization in hyperinsulinemic subjects

OBJECTIVE: To determine the effect of replacing some dietary carbohydrate with protein, during energy restriction, on weight loss, total energy expenditure (TEE), resting energy expenditure (REE), respiratory quotient (RQ), and the thermic effect of feeding (TEF) in subjects with hyperinsulinemia. DESIGN: Parallel, clinical intervention study of 12 weeks energy restriction (6.5 MJ/day) and 4 weeks energy balance (8.2 MJ/day) in two groups of subjects randomly assigned to either a high-protein (HP) diet (27% of energy (%E) as protein, 45%E as carbohydrate) or a lower-protein (LP) diet (16%E as protein, 57%E as carbohydrate). SUBJECTS: A total of 36 obese nondiabetic volunteers with hyperinsulinemia (10 males/26 females, aged 34-65 y, BMI 28-43 kg/m2, fasting insulin 12-45 mU/l). MEASUREMENTS: Body weight and composition, TEE, REE, and RQ were measured at baseline and at week 16. In addition, the TEF to an HP or LP meal was determined for 3 h, at baseline and at week 16. RESULTS: After 16 weeks, weight loss was similar in response to each diet; the overall decrease was 7.9±0.6 kg (P