SPECIAL COMMUNICATIONS: Letters to the Editor-in-Chief
The paper of van Essen and Gibala (5) presents a commonplace and gross mistake. In the methods section, regarding physical activity and nutritional controls, the authors state that all subjects received a standardized food parcel of 12.7 MJ, derived from 66% carbohydrate, 21% fat, and 17% protein. The total sum is 104%. What does the 4% in excess represent? Even if this does not affect the validity of the work, if the excess concerns fat, the diet would be very hypolipidic. Fat is important in athletes' diet because it provides energy, fat-soluble vitamins, and essential fatty acids. Additionally, ingestion of a high-fat diet results in high rates of fat oxidation and concomitant muscle glycogen sparing during submaximal exercise, even if this strategy seems not able to systematically improve exercise capacity (2). However there is some evidence that increasing the fat in diets, when calorie intake is sufficient to maintain an adequate intramuscular glycogen storage, increases V˙O2max and intramuscular fat in trained endurance athletes and can improve the time to exhaustion (4). In any case, there is no health or performance benefit in consuming an excessively low-fat diet (1). Restriction in dietary fat can reduce apolipoprotein A1 and HDL cholesterol and may have a detrimental effect on performance (3).
Department of Clinical Science
University of Parma
1. American College of Sports Medicine. Joint position statement: nutrition and athletic performance. Med. Sci. Sports Exerc.
2. Burke, L. M., and J. A. Hawley. Effects of short-term fat adaptation on metabolism and performance of prolonged exercise. Med. Sci. Sports Exerc.
3. Leddy, J., P. Horvath, J. Rowland, and D. Pendergast. Effect of a high or a low fat diet on cardiovascular risk factors in male and female runners. Med. Sci. Sports Exerc.
4. Pendergast, D., P. Horvath, J. J. Leddy, and J. T. Venkatraman. The role of dietary fat on performance, metabolism and health. Am. J. Sports Med.
5. van Essen, M., and M. J. Gibala. Failure of protein to improve time trial performance when added to a sports drink. Med. Sci. Sports Exerc.