In the days leading up to a race, a runner’s nutrition shifts from general health to strategic performance enhancement. The goal of pre-race fueling is to maximize energy storage within the muscles, maintain stable blood sugar levels, and ensure digestive comfort. Focusing on specific food types and precise timing allows runners to top off their fuel tanks. This provides the necessary energy reserve to perform optimally without the risk of gastrointestinal distress. Strategic eating and drinking in the final week and on race morning are as important as physical training.
Fueling Strategy in the Week Before
For races lasting longer than 90 minutes, such as a half-marathon or marathon, the week before the event is dedicated to carbohydrate loading, also known as glycogen supercompensation. This involves increasing the percentage of calories from carbohydrates to maximize the amount of glycogen stored in the muscles and liver. The goal is to shift the macronutrient ratio of the diet, not simply to eat more calories overall.
The strategy involves increasing carbohydrate intake to between 8 and 12 grams per kilogram of body weight per day in the final 2 to 3 days before the race. During this period, the runner should simultaneously taper training volume, allowing the body to store carbohydrates as glycogen. Since glycogen is stored with water, a slight weight gain is a normal sign of a successful load. Runners should favor complex carbohydrate sources like rice, potatoes, pasta, and bread. They should also reduce the intake of fiber and fat to ease digestion and prevent feelings of fullness.
Race Morning Nutrition and Timing
The final meal before the race is designed to top off liver glycogen stores, which deplete overnight, and to stabilize blood glucose. This meal must be simple, low in fat, and low in fiber to ensure rapid gastric emptying and prevent stomach upset. The timing of this meal is specific and depends on the race start time.
The main pre-race meal should be consumed 3 to 4 hours before the starting gun, allowing sufficient time for digestion. This meal should contain approximately 80 to 100 grams of easily digestible carbohydrates. A small amount of protein and fat can be included for satiety. Examples include oatmeal with honey, a plain bagel with jam, or white rice with a small serving of lean protein.
Closer to the start, about 1 to 2 hours before the race, a smaller, mostly carbohydrate snack can be taken. This snack should provide around 30 to 50 grams of simple carbohydrates, such as a banana, a handful of pretzels, or a low-fiber sports bar. Finally, 30 minutes before the race, a small dose of simple sugars, like an energy gel or a few ounces of a sports drink, provides a final, rapid fuel boost. Only consume foods that have been practiced and tolerated well during training runs.
Essential Hydration Strategies
Fluid intake is an important component of pre-race preparation, as dehydration can impair performance and increase the risk of heat illness and cramping. Runners should focus on consistent hydration throughout the week, aiming for urine color that is pale yellow. Over-drinking should be avoided, as this can dilute electrolytes and lead to hyponatremia.
On race morning, a strategic “pre-load” of fluid is recommended to ensure the body starts fully hydrated. This involves consuming 16 to 20 ounces of fluid, ideally with electrolytes, about 2 to 3 hours before the race begins. The added electrolytes help the body retain the fluid more effectively and replace what is lost through sweat.
About 15 minutes before the start, a final 6 to 8 ounces of water or a sports drink can be sipped. Monitoring urine color remains the simplest indicator of hydration status; dark yellow urine suggests dehydration, while clear urine may indicate over-hydration. This fluid and electrolyte balance is necessary for maintaining blood volume and regulating body temperature.
Foods to Avoid and Preventing GI Distress
GI distress is a common issue that can compromise race performance, making certain foods best avoided in the 24 hours leading up to the event. Foods high in insoluble fiber, such as beans, cruciferous vegetables, and large quantities of whole grains, are difficult to digest and can lead to bloating, gas, and diarrhea. Fat also slows gastric emptying, meaning high-fat foods like fried items, creamy sauces, and rich dairy products remain in the stomach longer and can cause nausea. High-protein meals take a long time to break down, diverting blood flow away from working muscles to the digestive tract.
Runners should be cautious with artificial sweeteners, particularly sugar alcohols ending in “-ol,” as these are known to have a laxative effect. While caffeine can enhance performance, excessive consumption should be avoided if the runner is not accustomed to it, due to its potential to stimulate bowel movements. Sticking to bland, low-residue, and familiar foods is the most reliable way to minimize the risk of stomach issues on race day.