Abstract des Autors

We studied the effect of moderate, short-term energy restriction on physical performance in physically fit men (n=13) and women (n=11) in a controlled clinical research setting with a metabolic kitchen, exercise testing laboratory and training facility. The experiment consisted of a 10 d baseline period followed by either 2 wk of dietary energy restriction (750 kcal/d; n=16) or energy balance (control; n=8). During this 24 day study, exercise energy expenditure averaged 465±5.7 kcal/d in all subjects and was accomplished through treadmill running at a self-selected pace. Body weight was maintained in the control group (-0.36±0.24 kg), but energy restriction resulted in weight loss of -1.29±0.16 kg (p<0.001). There was a trend for lean body mass to decline more in the energy restriction group (p=0.093), accounting for 61% of the weight loss, and urinary nitrogen excretion also tended to be higher in the energy restriction vs. control group (i. e., 13.2±1.1 vs. 11.2±1.0 g/d; p=0.089). Muscle strength (leg & shoulder press; 1 repetition maximum) was maintained or increased during the energy restriction period. Muscle endurance, assessed by leg squats to fatigue, and 5 mile run time improved following two weeks of energy restriction or balance. Anaerobic capacity (Wingate Test) increased slightly in the restriction (+ 368±219 joules) but declined in the control group 649±288 joules; p<0.05). We conclude that short-term (2 weeks) moderate energy restriction (~750 kcal/d) results in weight loss but does not impair performance in physically fit young men and women. Verf.-Referat