Get the right amount of nutrition for the swimming portion of the triathlon. A piece of toast or serving of fruit is a great way to elevate your blood sugar level before you hit the water. Don't consume a large number of calories or you may experience cramping or sluggishness. Bagels, low-fat muffins and other high-carbohydrate snacks like cereal bars, bananas, a sandwich, pasta and rice are great options. Limit your options to a snack or meal that is two-thirds carbohydrates and one-third protein and fat. While there is no specific amount of time you should wait after a snack or meal before you hit the water, Sound Medicine at Indiana University suggests waiting at least an hour.
Use water or sports drinks to curb dehydration and stave off low energy; however, dehydration is rare with swimming as your body temperature generally will not drop very low because of the cool water. Also, the swimming portion of the triathlon is the shortest of all three activities and requires the least amount of energy.
Unlike the swimming portion of a triathlon, the cycling route is more expansive and requires the most calories to meet the physical demands of the sport. Triathlon participants are encouraged to consume at least 400 to 500 calories in carbohydrates, protein and fat before any ride lasting an hour or longer. (Limit fat intake, but do not restrict calories below the recommended amount). Oatmeal or cold cereal, fruit and eggs (poached or hard-boiled) are ideal snack and meal options just before a ride. Other snacks to kick start your route include energy bars, bananas and other low-fat options like fig bars and dried fruit. Sports drinks are a great way to hydrate the body and replace electrolytes depleted during perspiration.
Running generally requires fewer calories than cycling. Snack and meal options include a small bowl of oatmeal or an energy bar. Aim for a balanced meal that includes low-fiber fruits and vegetables like zucchini, tomatoes, olives, grapes and grapefruit. Processed white foods are also a great option. Regular pasta, white rice and plain bagels are good choices. Avoid fried foods and cheeses, which can make you sluggish, deplete your energy and cause you to "crash" quickly.