A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults: implications for sarcopenic obesity.

The systematic review presented here assessed the effects of energy restriction (ER) and exercise (EX) on fat-free mass (FFM) in overweight and obese middle-aged and older adults. PubMed was searched using the key words "weight loss or energy restriction" AND "skeletal muscle or body composition," with limitations set for "human" and "middle-aged and aged." Results from 52 studies are reported as the percentages of EX (mainly aerobic training), ER, or ER+EX groups that had a specified change in body weight and FFM, since insufficient data were available for a meta-analysis. The EX groups had modest body weight and FFM changes. Eighty-one percent and 39% of the ER and ER+EX groups, respectively, lost > or = 15% of body weight as FFM. These findings suggest that exercise is an effective tool to help men and postmenopausal women aged > or = 50 years, with a BMI greater than 25 kg/m(2) preserve FFM after moderate ER-induced weight loss, which is important for combating sarcopenic obesity.