Background
Long-term dieting has been reported to reduce resting energy expenditure (REE) leading to weight regain once the diet has been curtailed. Diets are also difficult to follow for a significant length of time. The purpose of this preliminary proof of concept study was to examine the effects of short-term intermittent dieting during exercise training on REE and weight loss in overweight women.
Methods
16 sedentary women (37 ± 7 yrs, 162 ± 6 cm; 89 ± 17 kg; 42.5 ± 3% body fat) were assigned to an exercise & normal diet group (E, n = 6) or an exercise and diet intervention group (ED, n = 10). Diets were maintained for 30 days and consisted of 1,200 kcals/d for 1-wk followed by ingesting 1,500 kcals/d for 3-wks. Subjects then followed a 2,200 kcals/d maintenance diet for 4 wks and repeated the cycle each month for 6-months. Diets were either 45% CHO, 30% PRO, and 25% F or 45% PRO, 30% CHO, and 25% F. Subjects participated in a supervised Curves circuit training program 3-d per wk and walked for 30-min 3-d per wk. Body weight, DEXA body composition, and REE measurements were obtained at 0, 1, 2, 3, 4, and 5 months and were analyzed by repeated measures ANOVA. Data are presented as means ± SD changes from baseline for the E and ED groups, respectively, at 1, 2, 3, 4, and 5 months.
Results
Preliminary results revealed that subjects in the ED group lost significantly more weight (E 0.4 ± 2.9, -2.9 ± 2.5; -1.8 ± 4.1, -1.9 ± 5.1; ED -6.7 ± 3.0; -8.7 ± 4.5, -10.8 ± 6.7; -11.3 ± 7.3 lbs, p = 0.03) and tended to lose more fat mass (E 0.83.0, -3.0 ± 3.8; -1.0 ± 4.5, -1.5 ± 3.7; ED -4.4 ± 3.6; -6.4 ± 3.5, -7.5 ± 5.2; -7.5 ± 6.6 lbs, p = 0.11) than subjects in the E groups. REE rebounded after dieting during each maintenance phase in the ED group (E 19.4 ± 2.2, 19.1 ± 1.6, 18.4 ± 1.7, 18.4 ± 1.9; 18.2 ± 1.6; ED 19.0 ± 1.3, 18.1 ± 1.6, 19.3 ± 2.2, 18.2 ± 1.7, 18.6 ± 1.5, kcal/kg, O4 p = 0.004).
Conclusion
Preliminary results indicate that following 30 day cycles of dieting/maintenance can promote gradual weight loss while allowing for a rebound in REE during the maintenance phase. This strategy may be an effective way to promote weight loss without concomitant reductions in resting metabolism.
Acknowledgements
This study was funded by Curves International, Waco, TX.