Effect of High Protein Weight Loss for Seniors
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 96
- 试验地点
- 2
- 主要终点
- Change in 400 Meter Gait Walk Speed
研究概览
简要总结
Intentional weight loss in obese, older adults remains controversial. Although caloric restriction, resulting in significant weight and fat mass loss, ameliorates many clinical consequences of obesity, recommendation of intentional weight loss in aging remains controversial. Reluctance stems, at least in part, from loss of lean and bone mass known to accompany overall weight loss and potential exacerbation of age-related risk of disability and fracture. Accordingly, current treatment guidelines call fhttp://google.wfu.edu/or weight-loss therapy that minimizes muscle and bone losses for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.
Amount of dietary protein consumed during caloric restriction may be a key determinant in maintaining fat-free mass during weight loss. Adequate dietary protein is essential for skeletal muscle anabolism; and, epidemiological evidence in older adults point to a salutary effect of protein intake above the current RDA (0.8 g/kg/day) on body composition. Indeed, a recent position statement by the PRO-TAGE study group advises consumption of 1.0-1.2 g/kg/d in older adults during weight-stable conditions to aid in the maintenance of lean body mass and function. Practical achievement of this level of protein intake is often difficult for obese, older adults undergoing weight loss, yet may be critical to offset weight loss-associated lean mass loss. Preliminary data from our group show a lean mass sparing effect of high protein consumption during caloric restriction. In post-menopausal women undergoing a 5-month intentional weight loss program, consumption of a high (1.2 g/kg/day) versus low (0.6 g/kg/day) protein diet was associated with 50% attenuation (17% vs. 37%) of lean mass loss. While promising, results have yet to be translated to functional changes in a tightly controlled trial of weight loss in obese, older adults.
The primary goal of this study is to determine whether adherence to a high protein (≥1.0 g/kg/d) weight loss program results in improved physical function by favorably affecting body composition compared to weight stability in obese, older adults. This will be accomplished by conducting a 24-week trial in 124 obese (BMI 30-40 kg/m2), older (65-79 years) men and women, at risk for mobility disability, randomized to either: (1) high protein intake (≥1.0 g/kg/d; n=62) during weight loss, or (2) weight-stable control (n=62).
详细描述
Aging and obesity are prevalent risk factors for morbidity and mortality. By 2030, Americans aged 65 and older will number an estimated 72 million people,1 half of whom will be obese. Both advanced age and obesity are well-characterized risk factors for chronic disease and disability suggesting that the individual and societal health burden of age- and obesity-related conditions will increase substantially.
Emerging results from randomized controlled trials demonstrate caloric restriction and exercise interventions, resulting in weight loss of 7-10%, are associated with initial improvement in muscle strength and function in older adults; however, in few cases has the effect of caloric restriction, independent of exercise, been evaluated and no randomized controlled trials have examined the role of specific dietary components, as adjuvants to weight loss, on physical function. Evidence supporting a diet-based weight loss approach in obese, older adults with functional impairments has tremendous clinical significance as multiple behavior changes are often difficult to implement and maintain, and many older adults are unable (or unwilling) to engage in the amount of physical activity typically prescribed in lifestyle-based interventions.
In exploratory analyses we will also examine the effects of intentional weight loss on a compilation of physiologic and biochemical markers (including: respiratory and kidney function, cognitive processing speed, inflammation, and blood pressure), shown in epidemiologic investigations to predict mortality. Meta-analytic data from our group suggest a 15% reduction in mortality for obese adults undergoing intentional weight loss and better understanding of the potential mechanism(s) underlying this association is of great clinical interest.
Methods and Measures
Recruitment: We plan to recruit up to 124 obese (BMI=30-40 kg/m2), older (age=65-79 years) men and women with mobility disability from communities in and around Forsyth County, NC via media advertisements, mass mailings, and direct mailings.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 65 Years 至 79 Years（Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Age 65-79 years
- •BMI=30-40 kg/m2
- •Confirmation of self-reported mobility disability, as assessed by phone screen/clinical staff
- •Self-reported sedentary behavior
- •Non-impaired cognitive function (MoCA>18)
- •Stability of residence for next 2 years
- •Willing and able to follow dietary protocol
- •Willing to provide informed consent
- •Approved for participation by study physician
- •Not involved in another behavioral or interventional research study
- •Able to provide own transportation to study visits and Intervention
- •Not dependent on a cane or walker
- •No evidence of clinical depression, eating disorder, or other contraindications for participation in voluntary weight loss
- •English literacy
排除标准
- •Weight loss or gain (±5%) in past 6 months
- •Prior bariatric surgery
- •Multiple food allergies
- •Difficulty with hearing/vision that interferes with study participation
- •Excessive alcohol use (>14 drinks/week)
- •Smoker (>1 cigarette/d within year)
- •Insulin-dependent or uncontrolled diabetes (FBG >140 mg/dl)
- •Uncontrolled hypertension (BP>160/100 mmHg)
- •Abnormal kidney tests (GFR<40, creatinine >2.0)
- •Regular use of medications that may influence body weight or composition
- •Severe systemic disease (diagnosis of Parkinson's disease, chronic liver disease, systemic rheumatic condition, gout, thyroid disease, end stage renal disease) or other systemic diseases/abnormal laboratory values which would preclude participants from safely participating in the protocol or impair their ability to complete the study
- •Severe symptomatic heart disease or cardiovascular procedure within the past 3 months or history/current diagnosis/signs and symptoms of heart failure, with either reduced or preserved Left Ventricular ejection fraction
- •Cancer requiring treatment in past year, except skin cancers
- •Judged unsuitable for the trial for any reason by clinic staff
研究组 & 干预措施
Weight Loss Lifestyle Counseling
The high protein weight loss group follows the Medifast 4 & 2 & 1 Plan™, a 1200 calorie, high protein diet targeting ~10% weight loss over 24-weeks through a combination of meal replacement products (MRPs), meal plans, and individual nutrition/behavioral counseling. Participants are guided by the study RD on food purchasing and preparation and encouraged to consume only what is approved from the menu. Participants meet bi-weekly for RD-lead behavioral counseling group classes to provide support and introduce new topics in behavioral weight control. Weight is also measured at each session with progress feedback provided to increase motivation. Participants complete daily food logs to verify compliance to the diet.
干预措施: Weight Stable Group (Behavioral)
Weight Stable Lifestyle Counseling
The weight stable control group is monitored bi-weekly by study staff to ensure weight stability over the course of the study. During group sessions, participants are weighed and encouraged to maintain weight within ±5% of baseline. They also receive non-weight loss health related topics presented by study staff. If participants attend 75% of the educational sessions, all baseline and follow-up testing sessions, and maintain weight stability over the course of the study (defined as less than a 5% differential between weight measured at week 0 and 24), they will be eligible to receive up to 3 months of Medifast MRPs along with a 30-60 minute RD-led dietary instruction session on how to follow the Medifast 4 & 2 & 1 Plan.
干预措施: Weight Stable Group (Behavioral)
结局指标
主要结局
Change in 400 Meter Gait Walk Speed
时间窗: baseline and 24 weeks
Participants were asked to walk 10 laps of a 40-meter course (20 meters out and 20 meters back). The time it took to complete the 400 meters was calculated and reported in meters/second.
次要结局
- Change in 24-week Lean Mass Body Composition(Baseline and 24-weeks)