the Runner's Diet

by Stephanie Margolis, R.D.

Running can be a really convenient exercise, lace up the shoes and head out the door. You get a moment to move your body while also clearing your mind. You may have the right shoes, the ideal gear, but you also need to fuel your best to feel your best. A runner’s diet is extremely important whether you are running 3 or 13 miles.

Which Distance 5k 10k or (half) marathon?

If you are training for a 5k or 10k, you don't necessarily need to "add" extra foods.  That said, you need to fuel your body properly when adding in any exercise.

If you are adding distance running by training for a half or full marathon, that's when you need to add in the gels/chews, sports drinks and peanut butters.  It's also when you need to increase your food intake to maintain your energy and prevent weight loss.

Runs that are 60+ minutes require water and gels/chews to keep your body properly fueled during the distance.

Looking for a running plan that includes toning, flexibility and 5k, 10k, and half marathon distances?  Check out our Running Programs.


The best pre-workout snack is fruit!

Now we are going to get into the proper fuel for your body + how you should feed your body on a daily basis.

Runner’s Diet Plan
Just as it is important to create a training regimen that will prepare you for the race, it is vital to fuel your body well. Food is our fuel. While it is hard to always remember this, especially when your favorite treats pass under your nose!

All the fuel our bodies need for life, as well as exercise, are found in the foods we eat and what we drink. There are several nutrients we need, but for starters we will break it down into three main groups: Carbohydrates, Protein & Fat.

Each group has a specific role in our bodies.


These are the fuel for your body. Runners burn a lot of carbs, especially if they are training for long distances. The exact number of carbohydrates you burn per mile depends upon your fitness level, experience level, pace and running economy, but most marathon runners average around 110 calories per mile with about 75% of those calories coming from carbohydrates. A typical runner can store approximately 1800 calories worth of carbohydrate in their muscles, liver and blood. That amount of carbohydrate will be depleted in about 22 to 23 miles which explains why most marathon runners “hit the wall” at that point in the race.

When in the midst of training runners should be consuming a diet that is composed of between 50% and 70% carbohydrates.


Proteins are often called the building blocks of the body. Protein consists of combinations of structures called amino acids that combine in various ways to make muscles, bone, tendons, skin, hair, and other tissues. They serve other functions as well including nutrient transportation and enzyme production. Adequate, regular protein intake is essential because it isn’t easily stored by the body. Various foods supply protein in varying amounts with complete proteins (those containing 8 essential amino acids) coming mostly from animal products such as meat, fish, and eggs and incomplete protein (lacking one or more essential amino acid) coming from sources like vegetables, fruit and nuts. Vegetarian athletes may have trouble getting adequate protein if they aren’t aware of how to combine foods.

Athletes need protein primarily to repair and rebuild muscle that is broken down during exercise and to help optimizes carbohydrate storage in the form of glycogen. Protein isn’t an ideal source of fuel for exercise, but can be used when the diet lacks adequate carbohydrate. This is detrimental, though, because if used for fuel, there isn’t enough available to repair and rebuild body tissues, including muscle.

  • The average adult needs 0.8 grams per kilogram (2.2lbs) of body weight per day.
  • Strength training athletes need about 1.4 to 1.8 grams per kilogram (2.2lbs) of body weight per day
  • Endurance athletes need about 1.2 to 1.4 grams per kilogram (2.2lbs) of body weight per day
  • This typically turns out to be about 25% of an athlete’s total diet.


Dietary fat is often blamed for many health problems; however, fat is an essential nutrient for optimal health. Adipose tissue (stored fat) provides cushion and insulation to internal organs, covers the nerves, moves vitamins (A, D, E, and K) throughout the body and is the largest reserve of stored energy available for activity. Fat is stored when we consume more calories than we use. There is an optimal level of body fat for health and for athletic activity. When that optimal level is exceeded, too much dietary fat can lead to problems with health as well as athletic performance.

Types of Dietary Fat

Saturated fats are found primarily in animal sources like meat, egg yolks, yogurt, cheese, butter, milk. This type of fat is often solid at room temperature. Healthy diet has less than 10% of daily calories from saturated fats.

Trans Fats have undergone a process that increases its shelf life. This is called hydrogenation. These fats are known to raise your cholesterol and are found in processed foods, snack foods, cookies, some margarine, and salad dressings.

Unsaturated fats, including monounsaturated and polyunsaturated fat, are created from plant oils. These fast are considered “good fats” because they are known to reduce cholesterol levels in the body. In this group are the Omega-3 and Omega-6 fatty acids.

Pregnant or Breastfeeding? Diet Additions for You!
Young pregnant woman jogging down sidewalk in city.

If you are pregnant or breastfeeding, you can still run as long as your doctor has not indicated otherwise. The most important thing is to listen to your body and pull back if you begin to feel too fatigued or uncomfortable. It is very important during this time to stay hydrated. If you are breastfeeding, a lack of hydration can lead to a lack of milk production. During pregnancy, even mild dehydration can leave you cramping and fatigued. Knowing this, add an additional 16-20 ounces of water to your day and be sure to drink regularly throughout the day. Carrying water with you while you run is one way to stay hydrated; however, if you begin your run dehydrated, no amount of water you drink during the run will adequately re-hydrate your body.

If you are running just a few miles there is no need to adjust your caloric intake, unless you feel exceptionally hungry. If this is the case you may want to alter your meal timing, consuming a snack 30-60 minutes before a run and another snack 30-60 minutes after hitting the pavement. If you are training with higher mileage you do want to replace those calories by adding 300 calories. These additional calories are in addition to the extra calories your body needs in the 2nd and 3rd trimester. You may either do this by adding a snack or bulking up a meal. Keep these extra calories healthy by choosing produce, protein, whole grains, and good fats.

Are you a mom that wants to run again? Maybe you have never run before and a 10k is your goal. Check out our streaming workouts come with Running Hybrid calendars.

Read more about Running during Pregnancy.

© 2005-2023
Moms Into Fitness Inc.
All Rights Reserved