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

Abstract

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 ¼ 23) achieved a greater weight loss than the MP group (n ¼ 23) (9.4 vs 5.9 kg) (Po0.01). After 12 months, 8% had dropped out in the HP vs 28% in the MP group (Po0.07). 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 intraabdominal adipose tissue and more in the HP group (17%) lost 410 kg than in the MP (Po0.09). 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.

Randomized, multi-center trial of two hypo-energetic diets in obese subjects: high- versus low-fat content

“…4 However, it is very likely that the high protein content rather than the high-fat content is responsible for the weight loss effect with these diets. 7 Our results suggest that a larger proportion of obese subjects achieve a major weight loss, that is, more than 10%, and fewer will drop out on the low-fat diet. This is in line with previous ad libitum studies, [4][5][6] and suggests that energy from carbohydrate are slightly more satiating than those from fat also under conditions with a fixed energy deficit.…”

“…The intervention package included prescribed energy intake based upon an individually measured resting metabolic rate in contrast to others who used a fixed energy intake target. 7,8 A tailored dietary program was used, in contrast to one other study, which used a limited menu cycle, 6 and a high level of support was offered to the subjects.…”

“…5 While there is little evidence to support any important difference between low-fat diets with complex and simple carbohydrates, 6 higher protein levels might improve weight loss. 7 However, very few randomized trials have been conducted, which combine energy restriction and compare different levels of energy from fat and carbohydrate. These studies have included only small numbers of obese subjects and have therefore limited statistical power to detect clinically relevant differences in weight loss and body composition.…”

Long-term effects of popular dietary approaches on weight loss and features of insulin resistance

“…They reported no difference between the two diets, but attrition rates were very high. A more recent study by Due et al 18 found greater reductions in abdominal fat and a greater number of participants who had lost 10 kg or more among those on the HP diet than on the conventional diet. They also reported lower attrition rates on the HP.…”

“…Zone) 5 diets, which have been shown in many studies of free-living individuals to be associated with impressive weight loss and improved cardiovascular risk indicators over a relatively short period of time (up to 6 months). [6][7][8][9][10][11][12][13][14][15][16] Very few data are available relating to longterm (12 months or greater) comparisons of such alternative dietary regimens 6,[17][18][19][20] and only one study has been published that compares HP, HF and the more widely recommended HC-high-fibre diet over a prolonged period. 21 We have previously reported a 6-month comparison of such diets in overweight insulin-resistant women.…”