Long-Term Effects of Weight Loss and Supplemental Protein on Physical Function

项目摘要/摘要 肥胖加剧了与年龄相关的身体功能的下降，是行动不便的一个重要决定因素。 鉴于三分之一的老年人患有肥胖症，找出预防肥胖相关的有效疗法 身体机能的下降是迫切需要的。随着年龄的增长瘦体重的减少有助于与年龄相关的 身体机能的下降和目前的减肥建议可能会进一步加剧这种瘦身 质量。虽然在减肥状态下，减肥可以改善身体机能，但大多数人 不能成功地长期保持减肥。此外，来自中老年人的数据 这表明，减肥后的体重恢复是由比瘦体重更多的脂肪组成的。 因此，体重减轻和随后的体重回升可能会导致相对瘦身质量更低，甚至更糟 身体机能。在减肥过程中消耗的蛋白质的量可能是保持 减肥期间的瘦体重和减肥后较高的蛋白质摄入量可能会增强减肥效果。 通过减少总体体重来维持体重恢复，部分是通过促进瘦体重的恢复而不是脂肪的恢复。然而， 高蛋白饮食对瘦肉量保持和积累的潜在益处 减肥之后，肥胖老年人的身体功能会得到更大的改善 未知。我们的主要目标是确定高蛋白(1.2克/千克体重/天)/低碳水化合物 (CHO)肥胖老年人在为期6个月的减肥干预中的饮食改善身体功能 与等卡路里的低蛋白质(目前的RDA为0.8g/kg体重/天)/高CHO饮食相比， 在12个月的随访中继续高蛋白/低CHO饮食可以更好地维持 改善了身体机能。我们建议对225名肥胖者(BMI 30-40)进行为期18个月的随机试验 Kg/m2)，年龄较大(65-79岁)的有残疾风险的男性和女性(SPPB≤10)，以确定较高 在为期6个月的减肥干预期间进行蛋白质/低CHO饮食，随后进行12个月的随访 1)身体功能(通过扩展的短物理性能电池(Exp SPPB)、肌肉进行评估 力量和力量)，以及2)体重维持和身体成分(通过DXA和CT评估)。我们会 还要评估高蛋白/低CHO饮食对骨密度和骨密度的影响 心脏代谢危险因素。所有参与者将接受为期6个月的减肥干预，然后12 随机分为3组：1)6个月低蛋白质/高CHO饮食 减肥和12个月的随访阶段；2)6个月减肥的高蛋白/低CHO饮食 仅为阶段；或3)6个月减肥阶段和12个月随访阶段的高蛋白/低CHO饮食。 确定在减肥期间和减肥后高蛋白饮食是否能最大限度地发挥潜在的益处 对身体机能的影响，同时最大限度地减少减肥的潜在不利影响(例如，瘦和瘦 对于肥胖的老年人来说，更有效的减肥干预措施。

Project Summary/Abstract Obesity exacerbates age-related declines in physical function and is a strong determinant of mobility disability. Given that one-third of older adults are obese, identifying effective therapies that prevent obesity-related declines in physical function are urgently needed. The loss of lean mass with age contributes to age-related declines in physical function and current weight loss recommendations may further exacerbate this loss of lean mass. Although weight loss improves physical function while in the weight-reduced state, most individuals are not successful at long-term maintenance of weight loss. Furthermore, data from middle aged and older adults suggest that weight regain following weight loss is comprised of greater fat relative to lean mass. Consequently, weight loss and subsequent weight regain may lead to even less relative lean mass and worse physical function. The amount of protein consumed during weight loss may be a key determinant in preserving lean mass during weight loss and higher protein intake following weight loss may enhance weight loss maintenance by reducing overall weight regain, in part, by favoring regain of lean mass over fat. However, whether the potential benefit of lean mass retention and accretion with a higher protein diet during and subsequent to weight loss translates into greater improvements in physical function in obese older adults is unknown. Our primary goal is to determine whether a higher protein (1.2 g/kg body wt/d) / lower carbohydrate (CHO) diet during a 6-month weight loss intervention in obese older adults improves physical function compared with an isocaloric lower protein (current RDA of 0.8 g/kg body wt/d) / higher CHO diet and whether continuing a higher protein / lower CHO diet during the 12-month follow-up results in better maintenance of improved physical function. We propose to conduct an 18-month randomized trial in 225 obese (BMI 30-40 kg/m2), older (65-79 yrs) men and women at risk for disability (SPPB ≤10) to determine the effects of a higher protein / lower CHO diet during a 6-month weight loss intervention followed by 12 months of follow-up on 1) physical function (assessed by the expanded Short Physical Performance Battery (expSPPB), muscle strength and power), and 2) weight maintenance and body composition (assessed by DXA and CT). We will also assess the effects of a higher protein / lower CHO diet on changes in bone mineral density and cardiometabolic risk factors. All participants will undergo a 6-month weight loss intervention followed by 12 months of follow-up with randomization to one of 3 groups: 1) lower protein / higher CHO diet for the 6-month weight loss and 12-month follow-up phases; 2) higher protein / lower CHO diet for the 6-month weight loss phase only; or 3) higher protein / lower CHO diet for the 6-month weight loss and 12-months follow-up phases. Determining whether a higher protein diet during and subsequent to weight loss maximizes potential benefits on physical function while minimizing potential adverse effects of weight loss (e.g., loss of lean and bone mass) may lead to more effective weight loss interventions for obese older adults.