DIETARY FAT, CARBOHYDRATE BALANCE AND WEIGHT MAINTENANCE

膳食脂肪、碳水化合物平衡和体重维持

• 批准号: 3231590
• 负责人: JEAN-PIERRE FLATT
• 金额: $ 20.71万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3231590
• 关键词: albino mouse; bioenergetics; blood chemistry; body composition; calorimetry; carbohydrate metabolism; dietary carbohydrates; dietary lipid; exercise; fat body; fatty acid metabolism; free fatty acids; glycogenesis; hormone regulation /control mechanism; laboratory mouse; lipid biosynthesis; mass spectrometry; nutrient intake activity; nutrition related tag; obesity; oxidation; oxygen consumption; radioimmunoassay; respiratory gas analyzer; weight control

When the diet provides more than enough protein, weight maintenance is determined primarily by interactions between intake and oxidation of carbohydrates and fats. Since the body's glycogen reserves contain only about 1/100 of the energy stored as body fat, metabolic regulation and endocrine signals are poised to give priority to the adjustment of carbohydrate oxidation to carbohydrate intake. Furthermore, we found in ad libitum fed mice that the adjustment of food intake is more responsive to deviations from the carbohydrate than from the fat balance. Yet weight maintenance requires as well that fat oxidation be commensurate with fat intake. On diets with a substantial fat content, decreases in the rate within which glycogen reserves are kept an/or increases in the size of the adipose tissue mass are necessary to raise circulating free fatty acid levels enough to bring about the oxidation of a metabolic fuel mix with a fat-to-carbohydrate ratio equivalent to that of the diet. We will therefore determine how alterations of the relative proportions of different types of fats and carbohydrates in the diet modify the body composition for which the plateau of weight maintenance is reached in ad libitum fed mice. The reversibility of the dietary leverage will be studied by sequential assessment of the body fat content using body density measurements in lean and obese strains of mice. By measuring daily nutrient intake and the 24 hour respiratory exchange, we will determine the oxidation of carbohydrate and of fat, and their daily balances over many consecutive days. This allows for the first time to assess how changes in energy expenditure and in food intake, and of variations in the RQ contribute to the "corrective responses" which bring about maintenance of body weight, by compensating for temporary deviations from the glycogen, fate and energy balances. The influence thereon of hormones (e.g. corticosterone, thyroxin), of exercise, and of weight reducing drugs will be studied. By providing animals with diets inducing high rates of de novo lipogenesis, or by exposing them to variable degrees of cold, we will attempt to demonstrate that increases in energy expenditure do not necessarily lead to a reduction i body weight, as generally believed. The effect of spontaneous physical activity on energy expenditure will be measured, in order, among other, to obtain further in vivo data on differences in "net ATP yields" when carbohydrate or fate is oxidized. The main goals of the proposed investigations are (a) to characterize the impact of the diet's fat content and of the nature of the carbohydrates consumed on steady-state body composition under ad libitum feeding conditions, and (b) to delineate the relative importance of deviations from the carbohydrate, fat or energy balances int he spontaneous regulation of food intake. In time this may contribute to explain why a reduction in the diet's fat content facilitates weight maintenance at a lower level of adiposity, particularly individuals who are not physically active.

当饮食提供了足够的蛋白质，体重维持是 主要由摄入量和氧化之间的相互作用决定， 碳水化合物和脂肪。 由于人体的糖原储备只含有 约1/100的能量储存为身体脂肪，代谢调节和 内分泌信号准备优先调整 碳水化合物氧化对碳水化合物摄入的影响。 此外，我们发现， 自由采食的小鼠对食物摄入的调节反应更灵敏 与碳水化合物的偏离比与脂肪平衡的偏离更有关系。 然而 维持体重还需要脂肪氧化与 脂肪摄入量。 在含有大量脂肪的饮食中， 糖原储备保持和/或增加的速率 脂肪组织质量的大小是必要的，以提高循环自由 脂肪酸水平足以引起代谢燃料的氧化 混合脂肪与碳水化合物的比例相当于饮食。 我们 因此，将决定如何改变的相对比例， 饮食中不同类型的脂肪和碳水化合物改变身体 在AD中达到体重维持平台的组合物 自由进食的小鼠。 饮食杠杆的可逆性将是 通过使用身体脂肪含量的连续评估进行研究 在瘦型和肥胖型小鼠品系中的密度测量。 通过测量每日营养摄入量和24小时呼吸交换， 我们将确定碳水化合物和脂肪的氧化及其 连续多天的每日余额。 这允许第一 有时间评估能量消耗和食物摄入的变化， RQ的变化有助于“纠正反应”， 通过补偿暂时的 糖原、命运和能量平衡的偏差。 的影响 激素（如皮质酮，甲状腺素），运动， 将研究减肥药物。 通过给动物提供高比例的重新开始的饮食， 脂肪生成，或通过暴露于不同程度的寒冷，我们将 试图证明增加能量消耗并不 通常认为，这必然导致体重减轻。 自发的体力活动对能量消耗的影响将是 测量，以便获得关于以下的进一步体内数据： 当碳水化合物或命运被氧化时，“净ATP产量”的差异。 拟议调查的主要目标是：（a）确定 饮食的脂肪含量和碳水化合物的性质的影响 自由采食下稳态体成分消耗量 条件，以及（B）描述偏差的相对重要性 从碳水化合物，脂肪或能量平衡， 调节食物摄入量。 随着时间的推移，这可能有助于解释 减少饮食中的脂肪含量有助于保持体重， 较低的肥胖水平，特别是身体不健康的人 活跃