Dietary Macronutrients and Weight Loss

描述（由申请方提供）：关于肥胖症饮食治疗的长期结果的数据很少。强调限制脂肪、低碳水化合物或高蛋白质摄入的饮食在流行书籍中都有推广，但几乎没有证据支持一个比另一个更适合短期或长期使用。拟议研究的目的是测试4种不同常量营养素组成的饮食对减肥和体重维持的有效性：中等脂肪（35%能量），两种不同的蛋白质水平（15%和25%），低脂肪（20%能量），也有15%和25%的蛋白质。中等脂肪饮食将仿照地中海饮食。所有4种饮食方法都将是低饱和脂肪，并将涉及减少总能量摄入。所有参与者将接受两个中心标准化的最先进的行为治疗计划。我们将检验以下假设：较高的基线胰岛素、RQ和VO 2 max将与较小的体重减轻相关，并且在维持期间维持体重减轻的难度更大。饮食满意度和饱腹感将作为成功的潜在预测因素进行评估。400名男性和400名女性，BMI 27-39 kg/m2，将随机分配至4种饮食治疗组。每种饮食都将被开发为实用且适合公共卫生建议，并有望对心血管风险因素产生有利影响。主要结局变量为总体重从基线至2年的变化。与肥胖相关的次要结果是全身脂肪、内脏脂肪量、BMI以及腰围和臀围。其他结果包括血压、空腹血脂、载脂蛋白、胰岛素、血糖和血红蛋白A1 C。研究结果将直接适用于肥胖的公共卫生和临床指南，并将增加我们对肥胖和减肥生物学的理解。

DESCRIPTION (provided by applicant): There is a paucity of data on long-term results of dietary treatment for obesity. Diets emphasizing fat restriction, low carbohydrate or high protein intake are each promoted in popular books, but with little evidence to support one over the other for their short- or long-term use. The aims of the proposed research are to test the effectiveness for weight loss and weight maintenance of 4 diets differing in macronutrient composition: moderate in fat (35% energy) with two different protein levels (15% and 25%), and low in fat (20% energy), also with 15% and 25% protein. The moderate-fat diet will be patterned after a Mediterranean diet. All 4 dietary approaches will be low in saturated fat, and will involve reduction in total energy intake. All participants will receive a state-of-the-art behavioral therapy program standardized across the two centers. We will test the hypothesis that higher baseline insulin, RQ and VO2max will be associated with smaller weight loss and more difficulty maintaining the weight loss during maintenance. Dietary satisfaction and satiety will be assessed as potential predictors of success. 400 men and 400 women, BMI 27-39 kg/m2, will be randomized among the 4 dietary treatments. Each diet will be developed to be practical and suitable for public health recommendations, and would be expected to have a favorable effect on cardiovascular risk factors. The primary outcome variable will be change in total body weight from baseline to 2 years. Secondary outcomes related to obesity are total body fat, visceral fat mass, BMI, and waist and hip circumferences. Other outcomes include blood pressure, fasting blood lipids, apolipoproteins, insulin, glucose, and hemoglobin A1C. The results will be straightforwardly applicable to public health and clinical guidelines for obesity, and will increase our understanding of the biology of obesity and weight loss.