Effects of diet and diet-plus-exercise programs on resting metabolic rate: a meta-analysis.

Studies examining the effects of diet (D) and diet-plus-exercise (DE) programs on resting metabolic rate (RMR) report equivocal results. The purpose of this study was to use meta-analysis to determine if exercise prevents the decrease in RMR observed with dieting. Results from the 22 studies included in this analysis revealed that the majority of studies used female subjects ages 31-45 years, who were fed a relatively low-fat, high-carbohydrate diet of less than 5,023 kJ.day-1. The predominant prescribed exercise was aerobic in nature, 31-60 min in duration, performed 4-5 days per week, and of moderate intensity (51-70% of VO2max). Contrary to what is reported in narrative reviews, RMR decreased significantly with both D and DE programs, and the drop with D was significantly greater than that with DE. In conclusion, the addition of exercise to dietary restriction appears to prevent some of the decrease in RMR observed in premenopausal women.