You’ve trained hard for the big dance. And by now, you’ve put in all (or most) of the work. But when it comes to the week leading up to your 26.2-mile journey, lots of questions can pop up, including what to eat before a marathon.

It’s important to have a nutrition plan for the week leading up to the race, and even for the morning of the marathon. This will not only provide the perfect complement to your taper, but it will also get you to the starting line ready to run your best.

To guide you to the line healthy and strong through the finish, here’s what to eat the week of a marathon, as well as when to start carb-loading, and which foods you should cut back on ahead of race day.

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What should you eat at the beginning of marathon week?

During most weeks of marathon training, your muscles never have a chance to fully reload with glycogen. Runners and other endurance athletes simply need to back off on training for a few days, and the muscle enzymes responsible for restocking glycogen will gradually begin to store more carbohydrate, helping build up your energy reserves for race day.

About five to seven days before your scheduled race, make sure you’re consuming at least 3 grams of carbohydrate per pound of body weight during this time period to meet your needs, and space that carb intake out throughout the day. For example, a 130-pound runner would need to consume around 390 grams of carbs while a 180-pound runner would aim for 540 grams of carbs.

And seriously, don’t run too much. The taper exists for a reason. We know it’s hard to relax prerace, but doing so will set your body up with the proper fuel stores for success.

For reference, 400 grams of carbs might look like: 1 cup of oatmeal loaded up with 1 cup of strawberries, 1 cup of milk or soy milk, and 2 tablespoons of slivered almonds for breakfast. For lunch, three soft flour tortilla tacos with filling of your choice plus 1 cup of rice and beans on the side. A snack could be an apple plus 30 small crackers with 2 tablespoons of peanut butter for dipping and a glass of milk or soy milk. And for dinner: 1 cup of pasta topped with your favorite sauce, with a side of garlic bread.

When should you increase your carbohydrate intake?

Boosting carbohydrate intake to about 4 grams of carbohydrate for every pound of body weight about three to four days before your race will further increase your glycogen stores. That’s 520 grams of carbs for a 130-pound runner and 720 grams of carbs for a 180-pound runner.

That said—and this is important—that doesn’t mean loading up on calories with carb-rich foods on top of what you already eat; it means taking in the same amount of calories but getting a larger percentage of those calories from carbohydrates. The key is to back off on fat and protein to help balance your calorie intake.

Be aware that for every 1 gram of carbohydrate stored in the body (as glycogen), there is approximately 2 to 3 grams of water retained, so you may see your weight creep up a little, but this is normal water weight. It’s only temporary and nothing to worry about.

How to avoid an upset stomach come race day?

Before your marathon, you want to eat high-fiber foods in moderation. This means limiting foods such as bran cereals, whole grains, and large amounts of fibrous vegetables about two to three days prior to a race, as doing so can help you avoid GI distress.

Research from the Australian Institute of Sport shows that eating a lower fiber diet can help lighten the weight of material in the intestines. This may help you avoid the need for an urgent midrace pit stop that would otherwise add time to your race.

What should you eat the morning of the marathon?

Plan to eat your breakfast or prerun race meal about two to four hours before run time. Having a prerace meal supplies extra carbs to top off glycogen stores, particularly in the liver, which will help steady blood sugar levels during the race.

Aim for 0.5 to 1 gram for every pound of body weight (about 65 to 130 grams for a 130-pound runner or 90 to 180 grams for a 180-pound runner)—but only eat the higher range if you have four full hours to digest. Back off on fats and keep protein to about 15 grams or fewer—both nutrients take longer to digest. A study from the University of Minnesota found that for novice marathoners, eating a high-carb prerace meal was an important predictor of finishing times. Runners who ate ample carbs ran faster than those who skimped.

During your marathon, fuel up according to plan

In the weeks leading up to the marathon, you should have been testing different fueling strategies to find what works for you. During the race, put your training to work: Fuel up with at least 30 to 60 grams—and up to 90 or 100 grams if your gut tolerated it during training and you’re planning to race hard—of easily-digestible carbs per hour (spread it out, such as every mile or every 15 minutes or so).

Fluid intake should also go according to training, keeping the temperature in mind—sweat losses will be less in cooler weather. Studies show mild dehydration (one to two percent loss of body weight) will not hamper performance, so avoid over consuming fluids, which might just slosh around in your stomach.

If you feel yourself starting to fade during the second half of the race (and who doesn’t?), try a hit of caffeine (30 to 50 milligrams) from an energy gel, chew, or drink. Studies show this modest amount helps boost alertness and may provide a second wind.


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