Effect of Weight Loss on Physical Function in Overweight and Obese Individuals

Abstract

Impaired physical function is a major health concern in obesity across the adult life-span. Reducing weight and improving body composition may be critical for improving physical function in overweight and obese adults. PURPOSE: Investigate physical function before and during weight loss and study the relationships of body composition with changes in physical function. METHODS: Data were obtained from women (n=127, age 49.3±12.8 years; weight 101.8±17.9 kg; BMI 37.8±6.6 kg/m2) and men (n=17, age 54.4±10.1 years; weight 131.9±31.9 kg; BMI 40.5±9.9 kg/m2) enrolled in a medical supervised comprehensive weight loss program at Wake Forest Baptist Health Weight Management Center. Mean follow up was 6.7 months. Body composition, grip strength, gait speed, chair rise time, and submaximal VO2max were determined before and at the end of follow-up. Paired samples t-tests analyzed changes between baseline and follow-up. Pearson correlations examined relationships between pre-and-post functional performance tests and fat free mass (FFM), and fat mass (FM). RESULTS: Mean weight loss was 11.8±9.8 kg. Approximately 74.9% of weight loss was from fat mass: [FM (48.3±18.5 kg at baseline and 38.9±12.7 kg at follow-up, p<.001) and FFM (57.9±10.6 kg at baseline and 55.7±10.9 kg at follow-up, p<.001)]. Grip strength (29.3±8.1 to 32.9±11.2 kg, p<.001), chair rise time (9.1±2.9 to 7.8±2.7 s, p=.018), gait speed (1.2±0.2 to 1.3±0.2 m/s, p=.001), and submaximal VO2,max (32.7±3.9 to 34.7±4.5 ml/kg/min, p<.001) all improved from baseline to follow-up, respectively. Gait speed (r= -.292, p=.005) grip strength (r= -.215, p=.041) and chair rise (r= -.273, p=.009) changes were correlated with FM changes but not FFM changes. CONCLUSIONS: A comprehensive weight loss generally improves physical function. This improvement is possibly mediated by FM losses rather than FFM changes.