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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT00099151.

Figures

FIG. 1

In healthy overweight men and women, weight, FM, and FFM were reduced after 3 and 6 months of caloric restriction through diet only (CR) or diet in combination with exercise (CR+EX). There was no difference between the two intervention groups. Data represent change (mean ± SEM) from baseline. *, Significant change from baseline; †, CR different from control group; ‡, CR+EX different from control group.

FIG. 2

The distribution of visceral vs. nonvisceral fat in the whole body (measured by DXA) and the distribution of fat depot within the abdominal compartment (measured by CT) were not changed by 6 months of caloric restriction in over-weight men and women. The data for the CR and CR+EX groups are combined in this analysis (n = 24) and compared with the control group (n = 11). The figure shows the change in VAT and non-VAT fat between baseline and month 6 (M6; A) and the change in abdominal visceral, DSAT, and SSAT between baseline and at month 6 (B). The y-axis shows the contribution of each fat depot in kilograms, and the data within the columns are the percent contribution of the fat depot to the total compartment either whole body (A) or total abdominal (B). AT, Adipose tissue.