Effect of calorie restriction with or without exercise on body composition and fat distribution

Context: There is debate over the independent and combined effects of dieting and increased physical activity on improving metabolic risk factors (body composition and fat distribution). Objective: The objective of the study was to conduct a randomized, controlled trial (CALERIE) to test the effect of a 25% energy deficit by diet alone or diet plus exercise for 6 months on body composition and fat distribution. Design: This was a randomized, controlled trial. Setting: The study was conducted at an institutional research center. Participants: Thirty-five of 36 overweight but otherwise healthy participants (16 males, 19 females) completed the study. Intervention: Participants were randomized to either control (healthy weight maintenance diet, n = 11), caloric restriction (CR; 25% reduction in energy intake, n = 12), or caloric restriction plus exercise (CR + EX; 12.5% reduction in energy intake + 12.5% increase in exercise energy expenditure, n = 12) for 6 months. Main Outcome Measures: Changes in body composition by dual-energy x-ray absorptiometry and changes in abdominal fat distribution by multislice computed tomography were measured. Results: The calculated energy deficit across the intervention was not different between CR and CR + EX. Participants lost approximately 10% of body weight (CR: -8.3 +/- 0.8, CR + EX: -8.1 +/- 0.8 kg, P = 1.00), approximately 24% of fat mass (CR: - 5.8 +/- 0.6, CR + EX: - 6.4 +/- 0.6 kg, P = 0.99), and 27% of abdominal visceral fat (CR: 0.9 +/- 0.2, CR + EX: 0.8 +/- 0.2 kg, P = 1.00). Both whole-body and abdominal fat distribution were not altered by the intervention. Conclusion: Exercise plays an equivalent role to CR in terms of energy balance; however, it can also improve aerobic fitness, which has other important cardiovascular and metabolic implications.