The 24 hours before a triathlon are a highly influential window for nutrition and hydration. This final day is not about gaining new fitness or substantially increasing energy stores, which should have been accomplished during preceding days of carbohydrate loading. The most important goal is to top off the body’s glycogen reserves and minimize the risk of gastrointestinal (GI) distress during the race. Strategic eating and disciplined fluid intake in this period set the stage for optimal performance.
Prioritizing Glycogen Stores
The primary nutritional focus is ensuring muscle and liver glycogen stores are completely saturated. Glycogen, the stored form of carbohydrates, is the most readily available fuel source for high-intensity endurance work. Triathletes should aim for a high carbohydrate intake, potentially targeting 8 to 12 grams per kilogram of body weight, depending on the race distance and individual needs, continuing the carb-loading process.
The type of carbohydrate selected is important. Easily digestible, low-residue sources are preferred to minimize the workload on the digestive system. Excellent choices include white rice, plain pasta, white bread, and potatoes with the skin removed. These refined carbohydrates are quickly broken down and absorbed, efficiently moving into the muscle cells for storage.
Protein and fat intake should be significantly reduced compared to normal training levels. A moderate amount of lean, easily digestible protein, such as chicken breast or white fish, supports muscle repair. Fat intake must be kept low because fat slows down gastric emptying, which can lead to a heavy, uncomfortable feeling during the race.
Essential Foods to Avoid
Avoiding foods that pose a high risk for GI distress is a major component of the pre-race strategy. Any food that takes a long time to digest or creates significant intestinal bulk should be eliminated. The goal is to empty the gut before the race starts to prevent stomach upset.
High-fiber foods are the number one culprit to avoid, despite their benefits in a regular diet. This includes whole grains, beans, legumes, nuts, seeds, and most raw or cruciferous vegetables. Fiber is not digestible, meaning it passes through the system and can cause gas, bloating, and the need for unscheduled bathroom stops during the event.
Fatty and fried foods, rich sauces, and heavy desserts must also be avoided because they slow down digestion. High-fat items, like creamy pasta sauces or deep-fried appetizers, can linger in the stomach, increasing the risk of nausea and stomach cramps. Similarly, spicy foods should be removed, as they irritate the stomach lining and increase the likelihood of heartburn or indigestion.
The final rule is to avoid trying any new foods, drinks, or supplements. Even a minor change can introduce an unknown variable that the body is not accustomed to processing. Sticking strictly to familiar foods tested during training is the most reliable way to ensure digestive comfort.
Hydration and Electrolyte Strategy
Optimal hydration involves consistent fluid intake rather than aggressively consuming large volumes. Over-drinking plain water can dilute the body’s sodium levels, a condition called hyponatremia. The goal is to reach the start line in a state of euhydration, or proper fluid balance.
A practical method for monitoring hydration status is observing urine color. A light straw or pale yellow color indicates adequate fluid intake. If the urine is dark yellow or amber, fluid intake should be increased, but if it is completely clear, hydration may be excessive.
Incorporating electrolytes, particularly sodium, is beneficial for fluid retention and plasma volume. Adding a moderate amount of salt to meals or using a low-sugar electrolyte drink throughout the day helps the body hold onto the fluid consumed. This sodium preloading is especially helpful for athletes racing in hot conditions or those who are heavy sweaters.
Structuring Your Meals and Timing
Meal timing should be carefully managed to support continuous energy delivery without causing digestive discomfort. Instead of relying on three large meals, athletes should distribute carbohydrate intake across smaller, more frequent meals and snacks. This strategy prevents the bloating and sluggishness that can result from a single, massive intake of food.
A typical schedule begins with a substantial, carbohydrate-heavy breakfast and a moderate lunch, allowing a full 24-hour window for digestion. The most significant timing consideration is the final meal of the day, which should be consumed early, ideally between 6:00 PM and 7:00 PM. This early dinner ensures the stomach has sufficient time to empty before the athlete goes to sleep and before race morning begins.
A final, small, easily digestible carbohydrate snack, such as white toast or crackers, can be consumed before bed. This top-off helps sustain liver glycogen, which is partially depleted overnight, without introducing significant bulk. The entire day’s structure is designed to maximize energy storage while ensuring the stomach and intestines are settled and ready for the demands of the race.