Improved Function With Enhanced Protein Intake per Meal: A Pilot Study of Weight Reduction in Frail, Obese Older Adults.


BACKGROUND: Obesity is a significant cause of functional limitations in older adults; yet, concerns that weight reduction could diminish muscle along with fat mass have impeded progress toward an intervention. Meal-based enhancement of protein intake could protect function and/or lean mass but has not been studied during geriatric obesity reduction. METHODS: In this 6-month randomized controlled trial, 67 obese (body mass index ≥30kg/m(2)) older (≥60 years) adults with a Short Physical Performance Battery score of 4-10 were randomly assigned to a traditional (Control) weight loss regimen or one with higher protein intake (>30g) at each meal (Protein). All participants were prescribed a hypo-caloric diet, and weighed and provided dietary guidance weekly. Physical function (Short Physical Performance Battery) and lean mass (BOD POD), along with secondary measures, were assessed at 0, 3, and 6 months. RESULTS: At the 6-month endpoint, there was significant (p < .001) weight loss in both the Control (-7.5±6.2kg) and Protein (-8.7±7.4kg) groups. Both groups also improved function but the increase in the Protein (+2.4±1.7 units; p < .001) was greater than in the Control (+0.9±1.7 units; p < .01) group (p = .02). CONCLUSION: Obese, functionally limited older adults undergoing a 6-month weight loss intervention with a meal-based enhancement of protein quantity and quality lost similar amounts of weight but had greater functional improvements relative to the Control group. If confirmed, this dietary approach could have important implications for improving the functional status of this vulnerable population ( identifier: NCT01715753).





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Publication Info

Porter Starr, Kathryn N, Carl F Pieper, Melissa C Orenduff, Shelley R McDonald, Luisa B McClure, Run Zhou, Martha E Payne, Connie W Bales, et al. (2016). Improved Function With Enhanced Protein Intake per Meal: A Pilot Study of Weight Reduction in Frail, Obese Older Adults. J Gerontol A Biol Sci Med Sci, 71(10). pp. 1369–1375. 10.1093/gerona/glv210 Retrieved from

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Carl F. Pieper

Professor of Biostatistics & Bioinformatics

Analytic Interests.

1) Issues in the Design of Medical Experiments: I explore the use of reliability/generalizability models in experimental design. In addition to incorporation of reliability, I study powering longitudinal trials with multiple outcomes and substantial missing data using Mixed models.

2) Issues in the Analysis of Repeated Measures Designs & Longitudinal Data: Use of Hierarchical Linear Models (HLM) or Mixed Models in modeling trajectories of multiple variables over time (e.g., physical and cognitive functioning and Blood Pressure). My current work involves methodologies in simultaneous estimation of trajectories for multiple variables within and between domains, modeling co-occuring change.

Areas of Substantive interest: (1) Experimental design and analysis in gerontology and geriatrics, and psychiatry,
(2) Multivariate repeated measures designs,


Shelley R McDonald

Associate Professor of Medicine

Connie Watkins Bales

Professor in Medicine

Research in our laboratory focuses on the role of nutrition (particularly vitamins and minerals) in the prevention and management of chronic diseases in older adults. Previous studies have concerned trace elements and cardiovascular disease, calcium and osteoporosis, and renal synthesis of vitamin D as it relates to bone health. Some of our newest work emphasizes the role of micronutrients as antioxidants and their interaction with the aging process. We are also working on various aspects of energy balance in older adults, ranging from failure to thrive in stroke patients with dysphagia to exercise and nutrition effects in overweight subjects who begin physical training. Thus we have a number of clinical and epidemiological projects on-going, many of which include a strong emphasis on nutrition assessment techniques in middle-aged and elderly subjects.

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