The acute 1-week effects of the Zone diet on body composition, blood lipid levels, and performance in recreational endurance athletes.
ABSTRACT The aim of this study was to examine the effects of a 7-day Zone diet compared with a normal diet on maximal oxygen uptake (V(O)2 max), running time to exhaustion during endurance performance, and body composition. Eight men, with the following physical characteristics (mean +/- SE), participated in this study: age, 26.1 +/- 1.9 years; height, 178 +/- 1.7 cm; mass, 70.7 +/- 2.1 kg; and V(O)2 max, 54.6 +/- 3.1 ml x kg(-1) x min(-1). All subjects undertook pretesting for V(O)2 max, time to exhaustion (80% V(O)2 max), and body composition (Biostat 1500) before following either the normal diet or the Zone diet for 7 days. These performance trials were performed before and after the dietary period. There was a significant (p < 0.05) decrease in total energy consumption from a mean of 2,314 +/- 334 kcal on a pretest diet to 1,994 +/- 438 kcal on the Zone diet. Subjects showed a significant reduction (p < 0.02) in body mass from 70.7 +/- 2.1 kg to 69.8 +/- 2.1 kg. In the 80% V(O)2 max time to exhaustion trial, there was a significant reduction (p < 0.05) in time to exhaustion from 37.68 +/- 8.6 minutes for the pretest diet to 34.11 +/- 7.01 minutes for the Zone diet. In conclusion, the claim of the authors of the Zone diet that performance time and V(O)2 max can be improved was not shown in this 1-week research trial. We would suggest that this is not a nutritional strategy that athletes should use until further work has been conducted.
- SourceAvailable from: Aldo ScafoglieriContemporary Sport, Leisure and Ergonomics. Part I musculoskeletal loading, 11/2009; Routledge, Oxon.
- JAMA The Journal of the American Medical Association 05/2005; 293(13):1590; author reply 1590-1. DOI:10.1001/jama.293.13.1590-a · 30.39 Impact Factor
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ABSTRACT: Optimal nutritional intakes are critical for health- and skill-related physical fitness. This review details the effect of energy restriction and supplementation on physical fitness, discusses the optimal chronic macronutrient intakes for physical fitness in exercising subjects and finally overviews the impact of short-term intakes of carbohydrate and protein, before, during and after exercise, on physical fitness of athletes. The present standings highlight that it is essential that health care givers personalize nutritional advice to meet the specific needs of exercising individuals while applying the described recommendations. It reminds the difficulty of providing straight nutritional recommendations for physical fitness on the basis of evidence-based medicine.Clinical nutrition (Edinburgh, Scotland) 02/2010; 29(4):413-23. DOI:10.1016/j.clnu.2010.02.002 · 3.94 Impact Factor