Endurance athletes have higher energy needs because they spend a lot of energy during exercise. However, the metabolic differences between genders and if these differences will imply in dietary changes are still not clear. Thus, the objective of this study was to gather information from the literature on the differences between the genders regarding energy metabolism in endurance athletes. Some studies show that during long-lasting exercise, women use more lipids and less carbohydrates and proteins as energy source when compared with men. Yet, other authors have not found a difference between genders in the proportions of metabolized substrates but in the kinds of lipids used. This difference in the use of substrates has been related with distinct concentrations of some hormones in men and women, such as 17beta-estradiol, progesterone, testosterone, epinephrine, norepinephrine, growth hormone, insulin and glucagon. It has also been observed that male athletes increase their glycogen stores when they consume diets with a high sugar load while females only increase their glycogen stores when they consume diets with a high sugar load and excess calories. This finding is very relevant since the concentration of glycogen is directly associated with the athlete's performance during endurance exercise. Therefore, literature suggests that there are differences between the genders regarding the use of substrates in athletes. However, new studies are needed to better clarify the energy metabolism of endurance athletes and thus make more adequate nutritional recommendations.
foods for persons engaged in physical activities; endurance athletes; energy metabolism; sex