Carbohydrates consumed during exercise that lasts more than 60 minutes help the body maintain blood glucose availability late in exercise. Post-exercise carbohydrates help improve muscle glycogen storage, especially within 30 minutes after the activity. The body can store twice as much muscle glycogen after consuming sucrose or glucose than after fructose. Protein Protein is not the body's preferred fuel source during exercise, but it has a role to play in muscle growth and repair, and in boosting the immune system. Exercise can promote muscle protein loss due to reduced protein synthesis, increased protein breakdown and protein losses in urine and sweat.
Some athletes tend to overdo on protein, while others barely meet their needs.
Food is the easiest, most effective and least costly way to meet protein needs. If it seems difficult to meet the protein requirements, a scoop of nonfat dry milk powder added to milk, sauces or soups, or a sports bar that contains protein can help. This nutrient has gotten a bad reputation for increasing weight and disease risks. Fat is the primary energy substrate for low intensity and moderate exercise, and consuming too little fat may limit the duration and quality of exercise. Fat is an energy dense nutrient, providing nine calories per gram.