If you're like most runners, you spend the final days before your half- or full marathon feasting on high-carbohydrate foods. But a good nutrition plan doesn't end with that last plate of pasta the night before your race (learn the Truth About Carbo-Loading). Just as important is your pre-race breakfast, which helps restock the liver glycogen—or stored energy—that got depleted overnight.
"Liver glycogen keeps your blood-sugar level steady during exercise," says Jackie Berning, Ph.D., R.D., sports nutrition and metabolism professor at the University of Colorado at Colorado Springs.
Your morning meal provides fuel for your brain, helping to sustain motivation and concentration during a long race. But just how much should you eat on race morning to optimize your performance? Probably more than you think.
Here's how to choose the ideal amount and combination of foods and fluids to power you through to a strong finish.
More: Your Most Important Pre-Race Meal
The Right Stuff
The best pre-race breakfast consists mainly of carbohydrates, since they're digested most rapidly and are your body's preferred fuel source, says Penny Wilson, Ph.D., a Houston-based registered dietitian who works with endurance athletes.
Small amounts of protein will help stave off hunger during the later miles. Limit or avoid fat and fiber; the former takes too long to digest, while the latter can cause bloating and GI problems.
"I recommend foods like a bagel and peanut butter, oatmeal with milk and dried fruit or yogurt and toast," says Wilson.
Other good options include a banana and high-carb energy bar, waffle with syrup and strawberries or even a bowl of rice.
For runners who tend to feel queasy on race morning, sticking with liquid carbs can help prevent GI problems while still providing energy and hydration. Smoothies, juices, and sports drinks all pack quick-digesting carbs that empty easily from your stomach, says Wilson.
(Plus: Avoid the Top 5 Prerace Nutrition Mistakes.)
More: How to Carb-Load Before a Race
While your usual bagel and banana might power you through a morning of meetings, it's not enough to fuel you through a half- or full marathon.
Research shows that consuming 1.5 to 1.8 grams of carbohydrate per pound of body weight is ideal for improving performance, says Berning.
For a 150-pound runner, that translates to 225 to 270 grams of carbohydrates—or about 1,000 calories— which may sound like a lot just before a hard effort. The key is to get that meal in early, 3 to 4 hours pre-race to be exact, according to the American College of Sports Medicine. That gives you enough time to digest so your stomach will be fairly empty and your muscles and liver totally fueled.
If you're not sure you can stomach 1,000 calories at once, you can divide them up into two smaller meals, says Berning.
In that case, eat 200 to 400 calories four hours before the start, along with 12 to 20 ounces of water or sports drink—giving you plenty of time to hit the porta potty. Between 90 minutes and two hours before the start, eat most of the remaining carbs—again, choosing easy-to-digest options.
More: How to Fuel During a Half Marathon