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

• Published in: International Journal of Obesity Vol. 27; no. 5; pp. 582 - 590
• Main Authors: Luscombe, N.D, Clifton, P.M, Noakes, M, Farnsworth, E, Wittert, G
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.05.2003; Nature Publishing Group UK; Nature Publishing
• Subjects: administration & dosage; Biological and medical sciences; Body Composition; body mass index; Body weight; Carbohydrates; Diet; diet therapy; Diet, Reducing; dietary carbohydrate; Dietary Carbohydrates; Dietary Carbohydrates - administration & dosage; Dietary Proteins; Dietary Proteins - administration & dosage; Dietary restrictions; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Energy; Energy balance; Energy dissipation; Energy Metabolism; Energy Metabolism - physiology; Epidemiology; Exercise; fasting; Female; females; Food; Health aspects; Health Promotion and Disease Prevention; High-protein diet; Humans; hyperinsulinemia; Hyperinsulinism; Hyperinsulinism - diet therapy; insulin; Insulin resistance; Internal Medicine; low calorie diet; Male; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Nutrition research; Obesity; physiology; Proteins; Public Health; respiratory quotient; resting energy expenditure; Risk factors; Thermogenesis; Tumors. Hypoglycemia; volunteers; Weight control; Weight loss; Weight Loss - physiology; Womens health; Australia; South Australia Australia; weight loss; diet; energy expenditure; insulin resistance; protein; Endocrinopathy; Human; Resistance; Hyperinsulinemia; Energy; Diet; Weight loss; Restricted diet; Insulin; Protein
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/sj.ijo.0802270

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<0.001), of which 6.8±0.5 kg was fat (P<0.001). REE fell similarly with each diet; the overall decrease was 719±106 kJ/day (P<0.001). The TEF was 2% greater after the HP than after the LP meal at baseline (P<0.01) and 0.8% greater at week 16 (P=0.35). After 16 weeks, the TEF was not reduced in either dietary group. There was no change in TEE after 16 weeks. CONCLUSION: In subjects with hyperinsulinemia an energy-restrictive diet containing an increased protein-to-carbohydrate ratio does not enhance weight loss or significantly affect energy expenditure. Caloric restriction, rather than the macronutrient composition of the diet, is the most important determinant of weight loss.