Original articles  BODY COMPOSITION, NUTRITION, SUPPLEMENTATION 

The Journal of Sports Medicine and Physical Fitness 2010 June;50(2):189-95

Copyright © 2010 EDIZIONI MINERVA MEDICA

lingua: Inglese

Effects of short-term very low-carbohydrate or conventional diet on strength performance

Meirelles C. ^{1, 2}, Candido T. ¹, Gomes P. S. ¹ ✉

¹ Laboratory Crossbridges, Center for Interdisciplinary Research in Health, Department of Physical Education, Universidade Gama Filho, Rio de Janeiro, Brazil; ² School of Physical Education of the Army, Rio de Janeiro, Brazil

Aim. Weight reduction strategies usually include diet and regular physical activity. A very low-carbohydrate and high protein diet (VLCD) may be preferred instead of a low energy conventional diet (CONV). The effects of VLCD on strength performance are yet to be understood. Aim of the study is to determine the effects of two different restrictive diets on strength performance.
Methods. Sedentary women were assigned to either a VLCD (<40 g carbohydrate; n=12) or a CONV diet (500 to 800 kcal restrictive; 48%, 22% and 30% from carbohydrate, protein and fat, respectively; n=12). Knee extension isokinetic strength tests (3 ¥ 15 reps at 60°·s-1, with 90 or 180 s rest interval between sets) were performed prior and after a one week diet period.
Results. Both groups reduced body mass (VLCD: -2.6±1.0% vs. CONV: -1.9±1.3%; P<0.05), with no between diets effect. The sum of the total work in three sets (ÂTW) was 4850±1002 J vs. 4801±973 J with 90 s rest interval, and 4812±1174 J vs. 4812±1210 J with 180 s rest interval, respectively, in the pre vs. post-VLCD period. For CONV, values were 4709±729 J vs. 4530±996 J with 90 s rest interval, and 4760±732 J vs. 4816±702 J with 180 s rest interval, respectively, in the pre vs. post-CONV treatment. No significant differences were detected in the ÂTW between groups.
Conclusion. Short-term hypoenergetic diets, irrespective of the carbohydrate content, seem to reduce significantly body mass, but do not impair acute strength performance.