Short-term effects of weight loss with or without low-intensity exercise training on fat metabolism in obese men.
BACKGROUND
Energy restriction is known to induce a decline in fat oxidation during the postdiet period. Reduced fat oxidation may contribute to weight regain.


OBJECTIVE
The present study investigated the effect of the addition of low-intensity exercise training to energy restriction on postdiet fat oxidation and on the contribution of the sympathetic nervous system to fat oxidation.


METHODS
Forty obese men were divided randomly into 2 groups: diet (D) and diet plus exercise (DE). Both groups followed an energy restriction program for 10 wk. Subjects in the DE group also participated in a low-intensity exercise training program [40% maximal oxygen uptake (VO2max)] for 12 wk. Before the intervention and after 12 wk, with subjects at stable body weights, we measured body composition, VO2max, and substrate oxidation at rest, during exercise at 50% VO2max, and during recovery. Measurements were made with and without administration of the beta-adrenergic antagonist propranolol.


RESULTS
Both interventions led to significant decreases in body weight, fat mass, and fat-free mass (P < 0.001); these decreases did not differ significantly between the D and DE groups. Neither intervention significantly affected VO2max. The effect of the intervention on the respiratory exchange ratio differed significantly between the D and DE groups [two-way analysis of variance (ANOVA), P < 0.05]. The effect on the beta-adrenergic-mediated respiratory exchange ratio tended to be different between the 2 groups (two-way ANOVA, P = 0.09).


CONCLUSIONS
Addition of low-intensity exercise training to energy restriction counteracts the decline in fat oxidation during the postdiet period.
van Aggel-Leijssen
D P
DP
Nutrition, Toxicology, and Environmental Research Institute (NUTRIM), Department of Human Biology, Maastricht University, Maastricht, The Netherlands. d.vanaggel@hb.unimaas.nl
Saris
W H
WH
Hul
G B
GB
van Baak
M A
MA
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000328:Adult; D000704:Analysis of Variance; D004038:Diet, Reducing; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism* / Q000628:therapy; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D019518:Postprandial Period; D011433:Propranolol / Q000008:administration & dosage; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology; D013997:Time Factors; D015431:Weight Loss / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D005227:Fatty Acids; D011943:Receptors, Adrenergic, beta; D011433:Propranolol