Energy Expenditure and Gastric-Bypass Surgery

描述（由申请人提供）： 肥胖是一种流行病，对健康和社会有着广泛的影响。减肥手术是实现和维持体重减轻和改善肥胖合并症的成功疗法。这项研究将探讨胃旁路减肥手术受试者体重减轻的能量机制，到目前为止尚未明确定义。在任何情况下，有大量的变化，在能量储存，有必要研究的作用，在食物摄入量和能量消耗的变化。减肥手术后，很明显，能量摄入下降。然而，关于能量消耗的组成部分，特别是活动产热如何变化的信息很少。这不是一个微不足道的问题。事实上，身体活动和活动产热的变化对于理解为什么有些人比其他人通过减肥手术减轻更多体重至关重要。能量平衡包括能量摄入和能量消耗。能量消耗包括基础代谢率、食物热效应和活动产热。活动产热又可分为运动产热和非运动产热。后者比前者更难衡量。大多数美国人和绝大多数患有世界卫生组织III级肥胖症的人很少进行有目的的运动，因此大部分能量消耗在身体活动中是通过NEAT。本研究的目的是评估与术前相比，接受减肥手术的患者术后活动产热是否增加。我们将在术前即刻以及术后6个月和18个月使用经验证的体力活动监测系统和双标记水评估NEAT。这是为了评估最大体重减轻阶段和体重减轻达到稳定期时的能量消耗、活动产热和NEAT。这将使我们能够解决我们的主要假设，即与术前相比，在术后6个月和12个月接受减肥手术的患者中，活动产热作为每日总能量消耗的一部分增加。总体而言，肥胖是一个主要的个人健康和医疗保健负担。减肥手术已被证明是有益的，没有明确的机制理解。科学的需要存在，技术是可用的，以揭示活动产热和能量消耗在减肥手术后减肥的作用。这可能对减肥手术和一般的肥胖管理产生重大影响。

DESCRIPTION (provided by applicant): Obesity is an epidemic with widereaching implications for health and society. Bariatric surgery is a successful therapy for achieving and maintaining weight loss and improving obesity comorbidiities. This study will explore the energetic mechanisms of weight loss in subjects undergoing gastric bypass bariatric surgery, which until now has not been clearly defined. In any scenario where there are substantial changes in energy stores, it is necessary to examine the role of changes in food intake and energy expenditure. After bariatric surgery, it is evident that energy intake declines. However, there is very little information as to how the components of energy expenditure, and in particular activity thermogenesis, change. This is not a trivial issue. In fact, changes in physical activity and activity thermogenesis could be crucial for understanding why some people lose more weight than others with bariatric surgery. Energy balance comprises energy intake and energy expenditure. Energy expenditure includes basal metabolic rate, thermic effect of food, and activity thermogenesis. Activity thermogenesis can be further divided into exercise activity thermogenesis and non-exercise activity thermogenesis (NEAT). The latter is even more difficult to measure than the former. Most Americans, and the vast majority of those with World Health Organization Class III obesity engage in relatively little purposeful exercise, and hence the majority of energy expended in physical activity is through NEAT. The aim of this study is to assess whether activity thermogenesis increases in patients undergoing bariatric surgery post-operatively compared with pre-operatively. We will assess NEAT using a validated Physical Activity Monitoring System and doubly labeled water, immediately pre-operatively and again at six and 18 months post-operatively. This is to assess energy expenditure, activity thermogenesis and NEAT during the phase of greatest weight loss and once weight loss has plateaued. This will permit us to address our primary hypothesis that activity thermogenesis as a fraction of total daily energy expenditure increases in patients undergoing bariatric surgery six and 12 months post operatively, compared to preoperatively. Overall, obesity is a major personal health and health care burden. Bariatric surgery has been shown to be beneficial without a clear understanding of the mechanism. The scientific need exists and the technology is available to uncover the role of activity thermogenesis and energy expenditure in weight loss after bariatric surgery. This may have dramatic implications for bariatric surgery and obesity management in general.