An article from USA Swimming.



Everything we do influences our performance, but food choices have the greatest impact due to the long term and short-term benefits. A proper diet, including proper selection of foods from all 4-food groups, will help training and performance while also achieving a healthy lifestyle.

Since the swimmers are training daily throughout the week and competing 1 to 2 times a week, proper nutrition is essential. During training and competition, a diet high in carbohydrates is important. During the hour-long practices, the body burns mostly carbohydrate calories as its energy source. The best way to replenish calories lost during training is with a high carbohydrate diet. Eating foods or drinks high in carbohydrates within the first 30 minutes after training minimizes the depletion of energy stores.

To make sure your swimmer is getting the required nutrition, follow these nutrition do’s and don’ts: 


Do Don’t
Eat hot cereals like oatmeal or oat bran Choose sugary children’s cereals
Select whole-grain or high fiber cold cereals Choose fast food breakfast sandwiches & fat-laden croissants
Eat breads, including muffins, biscuits and bagels Eat doughnuts or pastries
Eat pancakes, waffles and French toast with fat-free toppings like syrups and jams Use too much margarine or butter
Choose fruit, including fresh, canned and juices Drink "Fruit Drinks" with little or no real fruit juice
Choose eggs up to 2 or 3 times a week Eat sausage, ham or bacon > 1 or 2 times a week
Try skim or low fat milk Skip Breakfast


Do Don’t
Choose lean meats like turkey Eat fatty and salty luncheon meats too often
Use mustard and ketchup as condiments Overuse condiments like mayonnaise or salad dressings
Pack a lunch when possible Eat fast-food meals too frequently
Eat pasta as much as you like, but choose tomato sauces rather than cream sauces Choose prepared salads containing excessive mayonnaise or salad dressings
Choose a hamburger over hot dogs Skip lunch
Choose a baked potato over fries  
Try pizza without fatty meat toppings  



Do Don’t
Eat pasta dishes Choose meals w/heavy cream sauces or gravies
Choose pizza w/vegetable and lean meat toppings Choose deep-fried meals more than twice a week
Try Chinese food w/ rice and fresh vegetables Eat high-fat meals like hot dogs or sausages in excess
Select fish often. Broiled or poached is best Use high fat dressings or toppings
Trim fat from meats & remove skin from poultry Ruin a baked potato or bread w/too much butter
Have soup, salads and lots of veggies Have cakes, ice cream & pies every night
Include potatoes, rice or beans when possible  
Choose fresh fruit, yogurt or jello for dessert  


Do Don’t
Pack nutritious snacks like fruit and nuts Count on potato chips or tortilla chips as good snacks
Have rolls, muffins and breads when you get a break Eat cupcakes or cream filled pastries to satisfy hunger
Snack on popcorn, pretzels and breadsticks Eat ice cream, cakes, or candies in excess
Drink 8 to 12 glasses of fluids, mostly water, a day Drink too many soft drinks or carbonated sports drinks
Drink non-fat or low-fat milk. Drink fruit juices, sparkling water or plain water  
Drink hot ciders, soups, and hot chocolate  

During the hot summer months, it is essential to keep your athletes hydrated. Encourage them to drink lots of fluids. Important additional sources include milk, fruit juices (100% juice not juice drinks) and sports drinks.