What to Eat When Training for a Marathon


75% of your fitness comes from what you eat. Competitive runners and endurance athletes know this as well as anyone. As your running endurance continues to progress, if you’re not feeding your body the right nutrients at the right time you will max out way under your potential. Factor founder Nick Wernimont shares his tips for what to eat when training for a marathon.

Your body is simply not getting the fuel it needs to rebuild muscle tissue and replenish energy stores so that you can improve on the day before. Here’s some guidelines for fueling your inner Marathon All-Star:

Eat to maximize your training:

  • Use an app or site to track what you’re eating so you can see where you might be falling short. It may surprise you that you’re not eating enough.
  • When planning meals, keep in mind 60-70% of your calories should come from low glycemic carbs which your muscles can easily use for fuel. – i.e. whole grains, vegetables, brown rice, quinoa.
  • Pack in the protein: Eat as much protein as a bodybuilder. You should be eating 1g for every kilogram of body weight.
  • Carb hard: Your carbohydrate intake will depend on your daily training time. If you train for 75-90 minutes, plan to eat a post-workout meal of 6-7g of carbs for every kilogram you weigh. For workouts over 90 minutes, bump up your carb intake to 7-8g per kilogram.
  • Eat simple, high-quality whole foods your body can digest easily: Veggies, fruits, nuts & seeds, whole grains, lean meats and fish.
  • You should eat every 3-4 hours, not 3 times a day.


Your most important meals:

  1. The night before: a balanced meal with complex carbs before your run; load up on simple carbs before bed
  2. The morning of: have a breakfast of 300-500 calories – this is mostly for brain function, your muscles have energy locked and loaded from the night before. Drink 24oz. of water in morning, then nothing in the final hour before the race.
  3. After the finish: it’s most important to properly time your reload meal which happens within 30 minutes of crossing the finish line, and each time you work out.

Mind over matter

Prepare yourself mentally; hitting the wall happens for most people around the 20-mile mark. This is caused from muscle glycogen depletion. Most runners have enough glycogen in their bodies to run 13.1 miles – after that point it’s essential to replenish.

Consider an energy gel, sports chew, or sports drink

But be careful to consume them at different intervals to avoid an insulin spike. This article from Runners Connect recommends different strategies for replenishing muscle glycogen efficiently.

Fat first?

New studies show that 10 days of fat-loading followed by three days of carb-loading is actually optimal for increasing performance times. “Ten days of fat-loading are enough to increase the muscles’ fat-burning capacity, while the subsequent three-day carbo load ensures muscles also have plenty of glycogen available.” (via Competitor) Check out a peer-reviewed study here.


Check in with us for how to maximize the final days of preparation for the big day!

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