The Effects of Overfeeding on OP and OR Women

描述（由申请人提供）：在美国和世界各地，肥胖是一个严重且日益严重的公共卫生问题。虽然短暂的正能量平衡可能会在所有人身上出现，但有些人能够抵抗环境对体重增加的压力，保持长期的瘦状态。该提案的中心论点是，理解个体对过度进食产生的短期正能量平衡的反应（代谢、能量和行为），可能为在当前环境中促进或防止体重增加的生物机制提供线索。虽然长期控制过度喂养的实验已经进行了多年，但以前没有研究系统地检查过短期过度喂养对饮食脂肪氧化、过度喂养后自发食物摄入或身体活动的直接测量的影响。此外，此前没有研究调查过这些变量与随后的体重增加之间的关系。据推测，那些在过度进食后优先氧化膳食脂肪、减少食物摄入和增加体力活动的个体将随着时间的推移保持苗条的表型。相反，那些没有做出这些适应的人会随着时间的推移而体重增加。拟建的研究将检验在1日饲喂基础能量140%的受控高热量饮食或3天的效果。2种膳食脂肪示踪剂的氧化饥饿、饱腹感、想吃东西和自发进食。直接测量的身体活动水平，在一组男性和女性中，富含可能保持苗条表型的个体和被选择为倾向于增加体重的个体。该队列将被跟踪3年，以确定每个受试者的体重增加率。基线测量将与随后的体重增加相关联，以确定哪种过度喂养的适应性反应与纵向确定的体重增加最相关。通过采用全面的方法来检查对过度喂养和未来体重变化的反应，拟议的研究将有助于阐明稳态调节机制如何协调响应短期正能量平衡状态。

DESCRIPTION (provided by applicant): Obesity is a serious and growing public health problem in the United States and around the world. While brief periods of positive energy balance likely occur in all people at one time or another, some individuals are able to resist environmental pressure towards weight gain, maintaining a chronic state of thinness. The central thesis of this proposal is that understanding the responses (metabolic, energetic, and behavioral) of individuals to short periods of positive energy balance produced by overfeeding, may provide clues as to the biologic mechanisms that either promote or protect against weight gain in the current environment. While long term controlled overfeeding experiments have been done for many years, no previous studies have systematically examined the effects of short-term overfeeding on direct measures of dietary fat oxidation, post overfeeding spontaneous food intake, or physical activity. Further, no previous study has examined the relationship between these variables and subsequent weight gain. It is hypothesized that those individuals who preferentially oxidize dietary fat, reduce food intake and increase physical activity following overfeeding will maintain a thin phenotype over time. Conversely, those who fail to make these adaptations will tend to gain weight over time. The proposed studies will examine the effects of a controlled eucaloric diet or 3 days of feeding 140% of basal energy on 1. The oxidation of 2 dietary fat tracers 2. Hunger, satiety, desire to eat and spontaneous food intake 3. Directly measured levels of physical activity, in a cohort of men and women enriched in individuals likely to maintain a thin phenotype and others selected for a propensity to gain weight. The cohort will then be followed for 3 years to determine the rate of weight gain in each subject. Baseline measures will be correlated with subsequent weight gain in an effort to define which adaptive responses to overfeeding best correlate with longitudinally determined weight gain. By taking a comprehensive approach to examining the responses to overfeeding and future weight changes, the proposed studies should help clarify how homeostatic regulatory mechanisms coordinately respond to a state of short-term positive energy balance.