Effects of energy restriction and macronutrient composition on weight loss, energy expenditure, and glucose, insulin and lipid levels in humans.

Abstract

Weight loss is essential in the management of obesity and obesity related diseases such as Type 2 diabetes mellitus and cardiovascular disease. Moderate energy restriction (-2000 to 4200 kJ less than average daily energy requirements) and a subsequent reduction in weight of as little as 5 to 10% may significantly improve blood pressure, fasting plasma glucose, and fasting serum insulin and lipids. There remains no consensus on the optimal macronutrient composition of weight loss diets apart from recommendations that the saturated fat content be kept low (< l0%). However, there is some concern that high-carbohydrate (50 to 60% of total energy), low-fat (< 30% energy) diets that are traditionally used for weight loss, may raise plasma glucose and serum triacylglycerol concentrations, and may reduce LDl-lipoprotein particle size. Within the dieting public, there has been a resurgence in the popularity of high-protein, low-carbohydrate weight loss diets. However, their efficacy in the treatment of obesity and Type 2 diabetes remains controversial. Several recent studies suggest that replacing some carbohydrate with protein, in low-fat diets, may blunt the diet-induced decrease in energy expenditure that is often observed after weight loss..