What should I eat?

Of all the questions a runner might ask before a marathon, half-marathon, or even a 5k, this is probably the most common. And it’s not easy to find an answer. There is a lot of conflicting advice in the running community, which has led to several very popular misconceptions.

For example, eating a big spaghetti dinner the night before your run will not make you faster. Proper pre-race nutrition should begin much earlier. Here’s an outline for the days leading up to the race, and the morning of:

One Week before the Race

Over the weeks or months of training, you craved plenty of protein, fats, and carbs. Now, even though your mileage has tapered, your hunger probably hasn’t.

Feed it. Now is a bad time to deprive yourself of anything. Your body is trying to reconstruct and re-energize itself. It needs nutrition; without it, you’ll likely continue to break down, resulting in sickness, fatigue, and even injury.

Three Days before the Race

This is when the well-known (and very enjoyable) “carb-loading” should begin. Carbohydrate-rich food like bread, rice, potatoes, and pasta should make up about 65-75% of your diet for the next few days. All those carbs turn into glycogen—the fuel your body uses on longer runs—which is stored for the race.

Carb-loading comes with some weight gain. Don’t let this psyche you out. Carbohydrates make your body retain more water, so you may gain up to 4 pounds in water weight before the race. It shouldn’t hurt your performance; on the contrary, more water will help you run.

Night before the Race

Most runners agree that your last big meal should be at least 12 hours before the race. If your race starts at 7:00 am, make sure you’ve eaten dinner by 7:00 pm the night before. And no matter how good the blackened oyster livers may sound, now isn’t the time to try anything exotic.

Pasta is great fuel, but only in moderate amounts and with some chicken or fish or broccoli mixed in. Tomorrow, when you’re standing on the starting line, your stomach will feel lighter and you more energized.

Morning of the Race

Your last meal should take place about three hours before the race itself. Wake up early if necessary to make sure you have time to digest. Few things will mess up a good race as quickly as an upset stomach.

As for what you should eat, try a small meal that’s low in fiber and fat. This meal should also give a lot of energy but without spiking your bloodsugar levels. The best foods contain complex carbohydrates with a low glycemic index. For example:

Sweet potatoes

Carrots

Cereal (avoid sugar and fiber)

Oatmeal (look for steel-cut or sugar-free)

Broccoli

Sourdough bread

These foods are packed with energy—lasting energy—and they won’t sit in your stomach during the race.

After all, with all the concerns you may have on race day, why worry about your stomach? Follow this easy outline, and you shouldn’t have to.