Triathletes are burning lots of calories. Make sure to be eating a balanced diet of fruits, veggies, healthy fats, grains, etc that correlates appropriately with the amount of training you are doing. If you are not eating enough calories, your body will not be able to keep up with the training load, and WILL break down. Always carry around a filled water bottle to be sipping on and snacks in your bag.
Eat an adequate breakfast (or snack) before each practice.
Before Saturday bike rides, eat on the heartier side so you have enough energy before a 2.5-4 hour ride. A Clif bar and OJ will not cut it on Saturdays. An example of a heartier breakfast could include eggs, toast and coffee/OJ, etc. However, each person has their own tolerance of how much they can/should eat, so a little trial and error may be necessary. As a general statement, running is harsher on an athlete’s GI system, so it is recommended to eat something a little lighter before run practices, such as peanut butter toast and a glass of water, and avoid dairy products.
For run and swim, bring a water bottle to sip on as necessary with a sports drink. A (light-sugar) sports drink with electrolytes is preferred because even in the pool when you can’t tell, you are sweating and losing salts.
For Saturday bikes, bringing an assortment of east-to-eat ride food is required
Eat something within a half hour of finishing your workout. The generally recommended guideline is 0.2 to 0.4g of protein and 0.8 grams of carbs for every kilogram of weight. Something like a peanut butter sandwich or chocolate milk works well. Eat a full meal within about 2 hours.
Eat breakfast first thing in the morning, at least two hours out from go time. Walk around in the morning with a bottle of sports drink to sip on. Eat a Gu to top off your system (and get caffeine in if you want a little extra “boost” but be careful with that) about a half hour before go time.
First rule is never race with something new-this includes nutrition. Your body can store 1500-2000 calories in glycogen, which is what your body burns through first when exercising (and if you burn through this completely without replenishing it, you “bonk”). For a sprint race, you do not need nutrition-your body has enough energy stored up. If you absolutely have a need for fuel, keep it to 100-200 calories (ex a Gu and a bottle of sports drink.) For an Olympic race, you need fuel. I would take in 200-300 calories in solid fuel (like a pack of Clif Blocks) and at minimum, one large bottle (22oz of sports drink) per hour. You will need more electrolytes/salts and water for hotter races. For raceday nutrition, there is a fine line between too much/running on a full stomach (that doesn’t feel nice) and too little and bonking. It’s important to practice what products to use and number of calories to eat while training, then implement that plan on raceday.