Moderate Walking Enhances the Effects of an Energy-Restricted Diet on Fat Mass Loss and Serum Insulin in Overweight and Obese Adults in a 12-Week Randomized Controlled Trial.

Background: Increased physical activity may be advantageous for weight loss.

Objective: We investigated the effects of an energy-restricted diet with and without moderate walking on body weight, body composition, resting energy expenditure (REE), and endocrine and cardiometabolic risk variables in overweight and obese participants.

Methods: A 12-wk, randomized, 2-arm, parallel, controlled, energy-restricted (500-800 kcal/d) dietary intervention study was conducted in 82 men and women [mean baseline characteristics: age, 39.4 y; weight, 99.3 kg; body mass index (in kg/m2), 31.9]. Participants were divided into 2 groups. One group received a hypoenergetic diet (DI) only (n = 44). The second group received the same DI and participated in a regular walking program of 2.5 h/wk (DI + walking; n = 38).

Results: After the 12-wk intervention, body weight was significantly decreased in the DI + walking group and the DI group (-8.8 compared with -7.0 kg, P = 0.064 for intergroup differences). The decrease in body weight was accompanied by a significant reduction in total fat mass, which was significantly more pronounced in the DI + walking group than in the DI group (-6.4 ± 3.1 compared with -4.8 ± 3.0 kg; P = 0.020). REE after 12 wk was not significantly different compared with the baseline REE. Diastolic blood pressure, mean arterial pressure, LDL cholesterol, and non-HDL cholesterol were similarly significantly improved by both interventions. In the DI + walking group, insulin and the homeostasis model assessment of insulin resistance index were also significantly reduced. Serum free triiodothyronine was significantly decreased and serum cortisol was significantly increased in both groups.

Conclusions: Participation in a 12-wk weight-loss study resulted in significant reductions in body weight and fat mass and was associated with significant improvements in biomarkers for cardiovascular disease risk. Moderate weight loss was not accompanied by a reduction in REE. Additional moderate walking enhanced the effects of a DI on fat loss and serum insulin. This trial was registered at www.germanctr.de/ and http://apps.who.int/trialsearch/ as DRKS00006827.