Active Voice: Exercise and Diet Promote Safe Weight Loss in Obese Older Adults
By Thomas W. Buford, Ph.D.

Active Voice is a column by experts in science, medicine and allied health. The viewpoints expressed do not necessarily reflect positions or policies of ACSM.

Thomas W. Buford, Ph.D., is an ACSM member and Lecturer in the Department of Aging and Geriatric Research at the University of Florida in Gainesville. His translational research focuses on investigating the causes of skeletal muscle dysfunction and frailty in advanced age, including exercise and dietary habits. Dr. Buford presented research related to this commentary at the ACSM Conference on Integrative Physiology of Exercise (IPE) held in Miami last month.

Recent census data indicate that the number of older adults (>65 years) in the U.S. is rapidly increasing and will continue to rise through the next half century. This increase in the older adult population will soon place significant strain on the country’s health care system, as age is an independent risk factor for numerous debilitating conditions. Additionally, approximately 35 percent of older adults are considered obese, putting them at an even greater risk for developing chronic diseases such as type 2 diabetes and cardiovascular disease. Thus, obese older adults are a particularly high risk group, and effective interventions are needed to improve body composition in these individuals.

Several studies have suggested that while dieting alone may induce weight loss, it may also exacerbate the loss of skeletal muscle in obese older adults and further compromise their physical function. Conversely, studies have shown exercise-only interventions to improve muscle function but not necessarily induce weight loss. Therefore, we conducted a randomized trial among obese older women to compare a weight-loss intervention that included both diet and exercise training to a control group that received education regarding healthy lifestyle choices. The trial examined the effects of the interventions on physical function, body composition and molecular signals relevant to skeletal muscle function.

Over the course of six months, women in the active intervention reduced their daily caloric intake by approximately 750 Kcal/day. Women in this group also performed supervised exercise routines including aerobic, flexibility and resistance components three times per week. Meanwhile, participants in the control group attended monthly health education lectures on topics relevant to older adults that were not related to weight loss, diet or physical activity.

As expected, the active intervention resulted in greater weight loss than did the control intervention. More importantly, the active intervention reduced body fat while improving physical function and maintaining muscle mass and strength. Finally, no difference in the frequency of adverse events was noted between groups. These data suggest that combining exercise with diet not only promotes weight loss but also safely maintains muscle and physical function in obese older adults. Future studies are needed to determine if the same result also occurs in men. These outcomes should be of particular interest to geriatricians and other clinicians who treat obese older adults. Based on the findings of this study, a calorie-restricted diet in combination with a comprehensive exercise program appears safe and effective for obese older women.