Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial

BACKGROUND: We have previously reported that a fat-reduced high-protein diet had more favourable effects on body weight loss over 6 months than a medium-protein diet. OBJECTIVE: To extend this observation by a further 6-12 months less stringent intervention and a 24 months follow-up. DESIGN: A randomised 6 months strictly controlled dietary intervention followed by 6-12 months dietary counselling period, and a subsequent 24 months follow-up, comparing an ad libitum, fat-reduced diet (30% of energy) either high in protein (25% of energy, HP) or medium in protein (12% of energy, MP). SUBJECTS: A total of 50 overweight and obese subjects (age: 19-55 y; BMI: 26-34 kg/m(2)). MEASUREMENTS: Change in body weight, body composition and blood parameters. RESULTS: After 6 months, the HP group (n=23) achieved a greater weight loss than the MP group (n=23) (9.4 vs 5.9 kg) (P<0.01). After 12 months, 8% had dropped out in the HP vs 28% in the MP group (P<0.07). After 12 months, the weight loss was not significantly greater among the subjects in the HP group (6.2 and 4.3 kg), but they had a 10% greater reduction in intra-abdominal adipose tissue and more in the HP group (17%) lost 410 kg than in the MP (P<0.09). At 24 months, both groups tended to maintain their 12 months weight loss, but more than 50% were lost to follow-up. CONCLUSION: A fat-reduced diet high in protein seems to enhance weight loss and provide a better long-term maintenance of reduced intra-abdominal fat stores.