Dietary Variety vs Dietary Fat Effects on Energy Intake

描述（由申请人提供）：饮食模式与宏量营养素组成在影响能量摄入和体重方面的相对重要性仍不确定。在这项研究中，我们建议调查膳食种类和膳食脂肪对成人自愿能量摄入的相对影响。具体来说，我们将量化和比较美国饮食中典型的种类和脂肪摄入量范围（基于美国国家调查数据）对自愿能量摄入的影响。要测试的主要假设是：(1)当已知的影响能量摄入的其他饮食因素保持不变（包括宏量营养素组成、适口性和其他食物种类）时，提供的主菜/配菜/零食/甜点种类的增加将以剂量-反应方式显著增加自愿能量摄入；(2)膳食种类和膳食脂肪对能量摄入的单独影响将相似。将招募健康、体重稳定的男性和女性（n=96，年龄18-45岁，BMI 20-35 kg/m2）进行为期39天的研究，并提供食物。三种不同水平的主菜/配菜/零食/甜点将在每一种饮食脂肪摄入量水平上提供，并且这些饮食操作对自愿能量摄入的相对影响，独立于潜在的混杂饮食因素，将被量化。受试者将被分配到三个bmi匹配组中的一个，在13天的三个阶段中，每个阶段以三种脂肪摄入水平（20%、35%或50%的能量）中的一种，每天提供4、8或12种主菜/配菜/零食/甜点。所有饮食的适口性、纤维、蛋白质含量和其他食物种类都要匹配，而且每个脂肪摄入水平下的能量密度也要匹配。通过测量24小时尿液PABA和渗透压排泄率来测量每日自愿能量摄入和监测饮食依从性。其他测量指标包括食物和膳食的适口性、饥饿感、食欲、饮食抑制解除、能量消耗、体重和身体成分。我们预计这项研究的结果将使我们更好地理解饮食模式与宏量营养素组成在肥胖病因学中的相对重要性，更具体地说，饮食种类与饮食脂肪在决定能量摄入方面的相对重要性。最重要的是，它将有助于为改善有关减肥和预防成年期体重过度增加的饮食建议奠定基础。

DESCRIPTION (provided by applicant): The relative importance of dietary patterns vs. macronutrient composition in affecting energy intake and body weight remains uncertain. In this study we propose to investigate the relative effects of dietary variety versus dietary fat on voluntary energy intake in adults. Specifically, we will quantify and compare the effects of typical ranges of variety and fat intakes in the American diet (based on U.S. national survey data) on voluntary energy intake. The primary hypotheses to be tested are (1) an increasing availability of entree/side/snack/dessert variety offered will significantly increase voluntary energy intake in a dose-response fashion when other dietary factors known to influence energy intake are held constant (including macronutrient composition, palatability and variety of other food items); and (2) the separate effects of dietary variety and dietary fat on energy intake will be similar. Healthy, weight stable men and women (n=96, aged 18-45 y, BMI 20-35 kg/m2) will be recruited for a 39-d study in which food is provided. Three levels of entree/side/snack/dessert variety will be offered at each of three levels of dietary fat intake, and the relative effects of these dietary manipulations on voluntary energy intake, independent of potentially confounding dietary factors, will be quantified. Subjects will be assigned to one of three BMI-matched groups that will be offered either 4, 8 or 12 entree/side/snack/dessert items/d at one of three fat intake levels (20, 35, or 50 % of energy) in each of three 13-d phases. All diets will be matched for palatability, fiber, protein content, and the variety of other food items, and also for energy density at each fat intake level. Daily voluntary energy intake will be measured and dietary compliance monitored by using measurements of 24-h urinary PABA and osmolar excretion rates. Other measurements include food and meal palatability, hunger, desire to eat, dietary disinhibition, energy expenditure, and body weight and composition. We anticipate that the results of this investigation will lead to a greater understanding of the relative importance of eating patterns vs macronutrient composition in the etiology of obesity, and more specifically, dietary variety versus dietary fat in determining energy intake. Most importantly, it will help lay a foundation for improved dietary recommendations concerning weight loss and prevention of excess weight gain in adulthood.