Physical activity and low-fat diet: Is it enough to maintain weight stability in the reduced-obese individual following weight loss by drug therapy and energy restriction?

Objective: The anthropometric and physiological effects of a physical activ ity (PA) and a mildly energy-restricted lowfat diet (LFD) follow-up program after a long-term dietary restriction were studied in 12 men and 8 women. Research Methods and Procedures: The dietary restriction (similar to 700 kc al/day) was accompanied by a fenfluramine (60 mg/day) or placebo treatment for 15 weeks, whereas the mean duration of the PA-LFD follow-up was 18 week s. Results: The long-term dietary restriction reduced body weight (-11.9 and - 7.6 kg, p < .001), fat mass (FM) (-10.6 and -5.8 kg, p < 0.01), resting met abolic rate (KMR) (-304 kcal/day, p < 0.01 and -148 kcal/day, NS) in men an d women, respectively. A decrease in fat-free mass (FFM) was also observed in women (-1.8 kg, p < 0.05). The PA-LFD follow-up preserved weight stabili ty at a reduced body weight and caused an additional significant decrease i n FM for men (-3.4 kg, p < 0.05). This part of the intervention also caused an increase in daily RMR for men (134 kcal/day, NS) to the point where thi s value no longer differed from the pre-energy restriction value. In contra st, RMR was further reduced in women (-200 kcal/day) to the point where it significantly differed from initial values (p < 0.01). Resting seated heart rate was reduced by the PA-LFD follow-up in men leading it to differ signi ficantly from both pre- and post-energy restriction values (-8.5 and -5.5 b pm, p < 0.01). Discussion: In conclusion, these results suggest that a PA-LFD follow-up ha s the potential to permit body weight stability and may even accentuate fat loss in the reduced-obese state. Moreover, resting energy expenditure is i ncreased under such conditions in men. These stimulating effects seem to be specific to energy metabolism since seated heart rate was either further r educed or remained stable in response to the PA-LFD follow-up.