Obesity has been steadily increasing over the past few decades, and has become a clear issue in our society today. Obesity is defined as a body mass index (BMI) above 30 kg/m2. In adults 65 years and older, 20% of the population is currently obese. This can lead to many complications in combination with increased age. These complications include worsening age-related decline in physical function, impairing quality of life, and increasing the amount of people entering nursing homes. As adults age their lean muscle mass declines, which can be exaggerated with weight loss. Prior to this study there was limited evidence for the negative or positive impacts that weight-loss had on physical function in obese older adults.
To determine whether or not weight loss by a combination of diet and exercise will produce a decline in obesity in older adults without producing any negative consequences to their health.
93 volunteers of 65 years of age or older went through randomization to complete this study. They needed to be obese, having a BMI of 30 or greater, live a sedentary lifestyle, and had maintained a stable weight over previous year. Additionally, their medications were required to be stable for at least six months prior to enrollment.
The volunteers were randomly split into four groups, taking into consideration the sex of the participant. The four groups were: control group, weight-management group (diet), exercise training group (exercise), and combination of both weight-management and exercise training group (diet-exercise). Diet group was given a calorie deficit of 500-750 kcal/day and included 1 gram of protein per kg of body weight per day. Exercise group participated in 90 minute sessions 3 times a week consisting of aerobics, resistance training, and flexibility/balance training. Diet-exercise group included both of these practices. The main goal was to assess the 12-month changes in physical health among all groups.
Reduction in physical health issues such as physical frailty was best in the combined diet-exercise group. This group also showed improvements in strength, balance, and gait. Rather than reducing lean body mass, it was found that physical functioning was further enhanced by the addition of exercise to diet. Second best results were seen in the diet alone and exercise alone groups, showing a smaller improvement for physical performance. The worst group was the control group.
One limitation of this study was that it did not take into consideration the sex of the volunteers which fails to show if there are any differences in results for males and females. Since the study was done with a small number of selected volunteers, it may not reflect the general obese, older adult population.
Weight loss or exercise alone improves physical function in older individuals, but the combination is the better option to improving overall physical health status.
The full report is titled “Weight Loss, Exercise, or Both and Physical Function in Obese Older Adults.” It is in the 31 March 2011 issue of The New England Journal of Medicine (volume 364, pages 1218-1229). The authors are D.T. Vilareal, S. Chode, N. Parimi, D. Sinacore, T. Hilton, R. Armamento-Vilareal, N. Napoli, C. Qualls, and K. Shah.
Written by Lian Cerella and Jennifer Kinsey, Dept. Nutritional Sciences, Rutgers University-NewBrunswick Edited by NJ Obesity Group faculty