WEIGHT-LOSS WITH LOW OR HIGH-CARBOHYDRATE DIET

OBJECTIVE: With obesity being recognized as an important cardiovascula r risk factor, it is important to determine the optimal hypocaloric di et for decreasing that risk. The goal of this study was to compare the effects of two hypocaloric diets of similar caloric value, but differ ing in carbohydrate content (25% and 45%). SUBJECTS: Sixty-eight out-p atients were followed for 12w. DESIGN: The patients were assigned to o ne of two groups that received either a low (25% CHO, n = 31) or a hig h (45% CHO, n = 37) carbohydrate hypocaloric diet (5.0 MJ/d, 1200 Kcal /d). RESULTS: After 12w, the mean weight loss was similar and did not differ significantly between the two groups: 10.2 +/- 0.7 kg (25% CHO) and 8.6 +/- 0.8 kg (45% CHO). Furthermore, loss of adipose tissue was similar, 8.1 +/- 0.5 kg (25% CHO) and 7.1 +/- 0.7 kg (45% CHO). Despi te a high protein intake (1.4 g/kg/ideal body weight) there was loss o f lean body mass: 2.2 +/- 0.4 kg (25% CHO) and 1.4 +/- 0.3 kg (45% CHO ). The waist/hip ratio diminished significantly (P < 0.001) and identi cally in both groups. The fasting blood glucose (even though normal, a long with cholesterol and triglyceride concentrations, were significan tly decreased after weight loss. The fasting blood insulin which was m ildly elevated before weight loss decreased more markedly with the 25% CHO diet compared to the 45% CHO diet (P < 0.003). The glucose/insuli n ratio improved significantly (P<0.05) after weight loss with both di ets (0.17 +/- 0.04 mmol/mU (25% CHO) vs 0.10 +/- 0.03 mmol/mU (45% CHO ). CONCLUSIONS: Neither diet offered a significant advantage when comp aring weight loss or other, metabolic parameters over a 12w period. Ho wever, considering the greater improvement of fasting blood insulin, t he glucose/insulin ratio and blood triglyceride, the low carbohydrate diet (25%) could be more favourable in the longterm. The improvement o f fasting blood insulin could be explained by the differences in monou nsaturated fat composition in the low carbohydrate diet.