Athletes burn enormous amounts of calories both in training and while competing. They often have difficulty consuming more calories than they burn, which is required to gain weight. According to the University of Arizona Cooperative Extension, proper nutrition and continued exercise prevent fat gain and leave athletes with additional muscle mass. High-calorie diets consisting of balanced nutrients are the healthiest and most effective way for athletes to gain weight.
A healthy high-calorie diet that won't add fat includes an additional 500 to 1,000 calories per day. According to the University of Arizona Cooperative Extension, the additional calories should be distributed evenly from the major food groups and include proteins and carbohydrates.
Healthy options for adding the additional calories can come from an increase in nutrient-dense snack foods such as peanut butter and pretzels, bagels, dried fruit, peanuts and almonds, yogurt, granola and low-fat cheese. Portions of healthy meal items can be increased to add extra calories to the day's total. Replacing fresh fruit with real fruit juice is an effective way to add calories. Drinking whole or low-fat milk instead of skin milk also brings added calories without losing nutritional value and maintaining a low-fat diet.
Most athletes want to build lean muscle to compete more effectively and increase strength. According to the University of Arizona Cooperative Extension, muscle weight takes more time to build than fat. An athlete typically can gain about one pound of muscle per week by eating a low-fat, high-calorie diet and continuing to exercise.
Although protein is essential to build lean muscles, muscle growth also is fueled by appropriate fat and carbohydrate consumption. An athlete cannot bulk-up by eating a high-protein diet to obtain additional calories. High-calorie liquid milkshakes and supplements can help athletes achieve higher caloric intake but do not provide any additional benefits to muscle growth than a balanced high-calorie diet from food.
Athletes who are vegetarians often have difficulty eating enough daily calories to sustain their activities. Adding calories to their daily intake poses a challenge. According to the American Council on Exercise, many athletes choose vegetarianism to lower blood cholesterol numbers, reduce their risk of developing cancer and improve overall digestive functions. The nature of the diet, however, often requires athletes to eat more than their stomachs can handle. When calorie consumption falls below energy requirements, the body compensates by burning muscle to provide needed protein. To compensate and build muscle with more calories, vegetarians must plan carefully and eat more carbohydrate-rich snacks and meals more often throughout the day.