Carbohydrates are the main source of fuels for muscular work during intense exercise above 65% of maximum effort. Carbohydrates are effective fuels for physical activity because they supply more energy per litre of oxygen consumed than fats or proteins. The nervous system senses carbohydrates as soon as they enter the mouth, and triggers the central nervous system to improve performance. The effect is not influenced by taste. For bodybuilders, using a carbohydrate mouth rinse might be helpful for promoting training intensity without increasing caloric intake.