What To Eat The Week Before A Marathon


Fueling for a marathon is just as important as training for one. Mess it up and you won’t have the energy to run your best race. But fuel properly, and you could just be on the road to a new PB!

But it’s also not just about your nutrition during the race. Learning what to eat the week before a marathon can make a huge difference—your diet is an underrated tool you can use to your advantage if you do it right.

Here’s our advice for fueling yourself the week before your big race, based on science and the experience of hundreds of runners!

Nutrition During Marathon Training

Marathon training takes between 12 and 16 weeks. You should pay careful attention to your nutrition throughout those weeks, not just the week before your marathon!

However, the week before the race can be particularly difficult to stick to your healthy diet, especially when tapering.

But this week is probably the most important diet week of your training, since what you eat and drink now can directly affect your performance on race day.

7 Days Before the Marathon

A week before your big race, you should be sticking to your calorie intake but lowering protein slightly and increasing your fruits and veggies.

This helps to build up glycogen reserves in your muscles and also takes some stress off your digestive system, as protein takes more energy to digest.

Pay more attention to your diet a week out. If you want to perform at your best, you should avoid cheating during this week!

3 Days Before the Marathon

This is where you should begin carbo loading. For these 3 days, you want to aim for 70 percent to 80 percent of your calorie intake consisting of carbs. In grams, this is roughly your body weight in lbs, multiplied by 4.

It’s extremely important to note that you can’t just binge on processed carbs. It’s important to choose good carbs, because processed carbs like donuts and pizza are mostly sugar and don’t have as much nutritional value. You’re only going to shoot yourself in the foot if you choose this route!

Instead, aim for healthy, nutrient-dense carbohydrates. Here’s a list of excellent carbs you should include in your diet during carbo-loading:

  • Brown rice
  • Whole grain pasta
  • Oats
  • Potatoes and sweet potatoes
  • Green vegetables
  • Squash
  • Bananas—high in potassium
  • Berries—rich in antioxidants

It’s also helpful to make sure you’re drinking 60 to 100 ounces of water a day from three days out and replace your electrolytes as if you were doing a hard workout every day.

This will ensure you’re well-hydrated by the time you get to the finish line, without overloading your system and making you feel weighed down.

2 Days Before the Marathon

On this day, you should have a solid meal in the evening, consisting of a good amount of carbs. This will be your last big meal before your race—from here on, you’ll be eating light meals, so you start your race light and strong rather than sluggish.

You can opt for pasta, a rice dish, or something starchy. Stay strong and don’t give in to your cravings for pizza, bread, or other processed carbs! These can lead to bloating and general discomfort that may last a few days.

Make sure you’re still drinking your 60 to 100 ounces of water and keeping up your electrolyte intake!

The Day Before the Marathon

We recommend sticking to multiple small meals throughout this day to avoid feeling sluggish. Keep your carbs up during the day.

It’s important to be careful about what food you eat on this day, especially because just one wrong choice can cause tummy issues! Avoid foods that are:

  • High in fiber
  • Rich in fats
  • Processed
  • Dairy
  • Spicy

It’s best to opt for bland foods over tasty ones today! Choose plenty of leafy greens, legumes, fruits, and grains. Remember, you’re still aiming for 70 to 80 percent healthy carbs, plus your water intake on this day.

On Marathon Race Day

Remember, nothing new on race day! You want a light breakfast that doesn’t weigh you down, but at the same time, you should eat around 100 grams of carbs and 25 grams of protein to replenish your glycogen stores, which will have depleted throughout the night.

Some good options are oats or porridge topped with fruit—bananas or berries are good choices—and a drizzle of honey, muesli, and milk, a bagel with peanut butter, banana, and honey, or toast with scrambled eggs.

You should eat this breakfast around 4 hours before starting time. This allows it time to get digested and find its way into your liver and muscles, so you’re ready for the start of your race.

At the same time as you’re having your breakfast, try to drink 60 to 100 ounces of water. This will give you plenty of time to flush out excess fluid, so you should start the race fairly hydrated but not overhydrated.

About 15 to 30 minutes before the race, have a quick and carb-filled snack. This could be an energy bar or, even simpler, an energy gel or chew. This will start you off with a bit of an energy burst.

Just remember if you’re taking a gel, make sure it’s something you’ve tried before, and your stomach can handle, and take it with water, or you’ll be at risk of stomach gripes!

Foods to Avoid Before a Marathon

We’ve already been through this a little, but here are foods you should avoid eating in the few days leading up to your marathon… As well as why you should be avoiding them.

Foods that are high in fiber naturally stimulate digestion and can have you running to the bathroom more often than usual. The same is true for foods high in fats, which can lead to an upset stomach.

Processed foods should be avoided, as they’re essentially empty calories. Most processed foods are also high in fats and very often high in sugar, which will give you a temporary spike in blood sugar levels, followed by a crash.

There’s also a slight threat of dairy causing stomach upset, so it’s best to avoid it completely during these days. Leave the sauces and spices off the food as far as possible.

And, of course, it goes without saying that you shouldn’t eat spicy foods in the days leading up to a race!

The Coffee Question

If good coffee is part of your everyday morning routine, by all means, have your coffee! The added caffeine can boost you, so there’s no need to forgo it on race day.

The optimal amount of caffeine is around 200mg, taken about an hour before the race. You should notice the effects of this as you start.

However, it’s important not to try this on race day unless you’ve experimented with it before and seen success.

Caffeine can stimulate the bowels, so if you’re doing it for the first time on race day, you may find yourself cramping or needing to stop and hide behind a bush an hour or so into the race!

Keep in mind that some energy gels also include caffeine. Make sure you organize your fuel so you don’t end up overloading yourself with caffeine—a cup of coffee followed by a caffeine-filled gel every 45 minutes is more likely to lead to stomach issues.

Does Weather Impact Nutrition?

This is a common question, but the weather on race day doesn’t change what you should eat. You still need a breakfast with around 100 grams of carbs and 25 grams of protein.

However, if the weather is expected to be particularly hot, it’s a good idea to pay a little more attention to your hydration and electrolytes.

You can get a headstart on this by adding more salt to your breakfast than you normally would, or getting an electrolyte tablet into your system before your race begins.

The weather will, however, play a bigger role in your nutrition and hydration during the race. Even if it’s cool, though, don’t forget to stay hydrated—when you start to feel thirsty, you’re already dehydrated, so make sure you’re constantly sipping throughout the race.

Final Thoughts

Training for a marathon is a long-term thing. You’ll need to stick to a healthy diet for 12 to 16 weeks as long as you’re training. But this last week can make or break your performance on the day, no matter how well you’ve trained.

Don’t let your diet be the reason you miss that PR! Follow these tips for what to eat the week before a marathon, and you’ll be in the best possible position to perform well and hit the times you’re aiming for.

Photo of author


Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.