What Should I Eat During Marathon Training?

We’re talking about what to eat during marathon training, so right away – BIG DISCLAIMER! There are lots of ways to get from point A to point B when it comes to fueling. Lots of different diets and bodies, and lots of different ways to be adequately fueled for the major work you’ll be putting in while prepping for your marathon. Here, I’m sharing my favorite ideas on how to set yourself up for success during training. One of my favorite sources and my guide for writing this article is Matt Fitzgerald’s book Runner’s World Performance Nutrition for Runners. I also share many valuable resources to help you make the best decisions for you for what to eat during your marathon training. Let’s dive in! 

Along with answering the question of what you should eat during marathon training, when you eat often matters just as much for athletes training for long races. The challenge for most runners is which foods are best and which foods should be avoided. When I trained for my first marathon, many years ago, I started losing a lot of weight during my training. My performance in workouts and long runs started to suffer. I wasn’t overtraining, instead, I simply wasn’t eating properly to fuel my workouts and refill my tank. The best diet for marathon training includes a variety of healthy foods consumed prior to and after your workouts.  In addition to eating a healthy diet during training, marathoners should also be well-hydrated before beginning each workout. Drink enough fluid during and after exercise to balance fluid losses. 


As you increase mileage and intensity during marathon training, you will need more calories compared to someone who is just working out a few times/week. To best know what and when to eat, it’s important to understand the role of basic food groups. Too much of one and not enough of another macronutrient can lead to poor performance.  

  • Carbohydrates provide an important, but relatively short lived supply of fuel for exercise. This is why as much as 70% of daily caloric intake should come from carbohydrates (examples discussed below). Carbs help to fuel your training and optimize recovery between workouts. Complex carbs are the best because they pack more nutrients than simple carbs which often have refined sugar.  Examples of simple carbs include cookies, soda & breakfast cereal.
  • Although carbs may seem like the key to fuel your running, protein is also essential because it stabilizes your blood sugar and helps you feel fuller longer.  However, protein is not a fuel source, instead it stimulates the muscle-repairing process. Insufficient protein in a runner’s diet can result in slower recovery from workouts, weaker adaptations to training and increased risk of illness, overtraining and injury. Athletes training for a full marathon must consume an adequate amount of protein to avoid these pitfalls.  Older runners require more protein, so Master runner’s need to keep this in mind.
  • Fat is the primary fuel for light to moderate intensity exercise. Fat is a backup source of fuel when you’ve depleted your carb storage. Examples of healthy fats are discussed below.  The more efficient a runner becomes, the easier it is to use fat as fuel at a lower intensity.

If you’re curious about how much of the foods in these food groups you should consume, you can look to the National Institute of Health’s article on supplements and dietary needs for some guidelines.. They provide the following daily breakdown of carbs, proteins & fats for athletes. Be aware that these ranges are broad, because the percentages that work best for athletes varies. 

  • Carbohydrates – 1.4 to 4.5 g/lb body weight (40 – 70% of daily caloric intake)
  • Proteins – .55 to .9 g/lb body weight (15 – 25%)
  • Fats – 1.2 to 2.0 g/lb body weight (20 – 40%)


The best plan is to track what and when you eat throughout your training.  This way adjustments can be made. Eat carbs prior to and after your run. In fact, eating easily digestible carbohydrates in the hour before long runs generally enables runners to work out longer. If your run is longer than an hour, plan on bringing or having access to carbohydrates and fluids. Some sports drinks contain both. Finally, after an intense or long run, eat carbs and protein immediately (30 – 45 minutes after the workout).  Some of the best post-workout snacks include chocolate milk, yogurt with fruit, a fruit or green smoothie or even a peanut butter and banana sandwich.

Fats can be consumed anytime, but remember, they won’t be of much help right before a workout.  Ultimately, through trial and error, you’ll make adjustments to your diet and dial in the foods that make you feel and perform your best.


My team works with a Registered Dietitian when it comes to analyzing our athletes’ dietary needs.  She recommends the following guide when planning a meal.  Simply visualize your plate as having 3 separate sections as follows:

  1. Colorful low starchy vegetables & fruit 
    1. Spinach, mixed greens, red, orange & yellow peppers, tomatoes, carrots, broccoli, kale, beets.  
    2. Pears, bananas, berries, oranges, pineapple, raisins, dates
  2. Minimally processed carbohydrate rich foods
    1. Beans, lentils, hummus, peas, potatoes, quinoa, brown rice, plain yogurt, whole grain bread, whole grain pasta
  3. Lean protein rich foods
    1. Salmon, tuna, skinless poultry, eggs, lean red meat, beans, tofu


Fresh fruits & vegetables need to top your list of foods you should eat. In addition to providing carbohydrates for energy, fiber for digestion and vitamins and minerals, fruits and vegetables give us phytonutrients which promote faster post-workout recovery, tissue healing and reduce the risk of injuries, sickness and fatigue from overtraining.  Just like running a variety of workouts is the best way to train, I strongly recommend consuming a diet that is high in a variety of colored vegetables & fruits (think green leafy, bright red and orange). 


I’m often asked about snacking, because marathon training can make an athlete very hungry.  It’s important not to sabotage our training by snacking on packaged foods that are essentially “empty calories” that won’t fill you up.  We need foods that will help us fuel and recover from our workouts while satisfying our hunger. Following are some good ideas.

  • Small bag of assorted nuts (cashews, almonds, dried walnuts)
  • Smoothie with yogurt and berries
  • Crackers with peanut butter + low fat chocolate milk
  • Sports drink with nuts and/or crackers with nut butter

If you’re still asking, “how much of each food category should I be consuming,” use the following table as a daily guide to eating during your marathon training.  Think of a serving size as the amount of food you’re supposed to eat during a meal.  For example, a single serving of meat or fish is 4 – 5 ozs, while a serving size of rice or pasta is ½ cup.  This chart can help you identify any shortcomings in your diet so you can make appropriate adjustments. 

Runners training for a marathon need to consume a wide variety of foods that will meet their energy needs. There’s not a single ideal amount of carbohydrates, protein, fat or other nutrients that will work for all athletes.  Every runner is different. Understanding exactly how to fuel your body with the right nutrition is a process that involves some trial and error, but it’s vital to your success.  

Here are some tips from the folks at the Academy of Nutrition and Dietetics: .

  1. Start with a full tank. It’s important to begin all exercise well hydrated and with adequate muscle fuel. 
  2. Be willing to try new products and foods and when to eat them during your training sessions.  This includes before, during and after your workouts.  This flexibility will help you determine the type & amount of food and fluid and time that work best for you.
  3. Consume fluids early and consistently to replace sweat losses. Don’t wait until you’re thirsty.

By putting in the work to learn what to eat during marathon training and when to eat it, you can be confident that you have the best possible nutritional preparation to go the distance. You put in the effort to train hard for your marathon, and you owe it to your body and to yourself to put just as much effort into fueling so that you get the most out of your training efforts! 

portland running coachDan Lyne is a coach with Team RunRun. To learn more about him or work with him, check out his coaching page.