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.

当饮食提供足够的蛋白质时，维持体重就很重要 主要由摄入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仅包含 大约1/100的能量储存为体内脂肪、代谢调节和 内分泌信号准备优先调整 碳水化合物氧化为碳水化合物摄入。 此外，我们发现在 随意喂养的小鼠对食物摄入量的调整反应更灵敏 碳水化合物的偏差比脂肪平衡的偏差更重要。 然而 维持体重还需要相应的脂肪氧化 与脂肪摄入量有关。 在脂肪含量较高的饮食中， 糖原储备保持和/或增加的速率 脂肪组织块的大小对于提高循环自由度是必要的 脂肪酸水平足以引起代谢燃料的氧化 与饮食中的脂肪与碳水化合物的比例混合。 我们 因此将决定如何改变相对比例 饮食中不同类型的脂肪和碳水化合物会改变身体 在ad中达到体重维持平台的组合物 随意喂养小鼠。 饮食杠杆的可逆性将是 通过使用身体连续评估身体脂肪含量进行研究 瘦和肥胖小鼠品系的密度测量。 通过测量每日营养摄入量和24小时呼吸交换， 我们将测定碳水化合物和脂肪的氧化，以及它们的氧化 连续多日的每日余额。 这允许第一个 评估能量消耗和食物摄入变化的时间，以及 RQ 的变化有助于“纠正反应”， 通过补偿暂时的体重来维持体重 糖原、命运和能量平衡的偏差。 影响力 激素（例如皮质酮、甲状腺素）、运动和 将研究减肥药物。 通过为动物提供诱导高新发率的饮食 脂肪生成，或者通过将它们暴露在不同程度的寒冷中，我们将 试图证明能量消耗的增加不会 正如人们普遍认为的那样，必然会导致体重减轻。 自发体力活动对能量消耗的影响为 测量，除其他外，以获得进一步的体内数据 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) 描述 饮食脂肪含量和碳水化合物性质的影响 随意进食时消耗稳态身体成分 条件，以及 (b) 描述偏差的相对重要性 来自碳水化合物、脂肪或能量平衡的自发性 食物摄入量的调节。 随着时间的推移，这可能有助于解释为什么 饮食中脂肪含量的减少有利于维持体重 肥胖程度较低，尤其是身体状况不佳的人 积极的。