Going the Distance: How to fuel your body for long-distance running

If you’re a long-distance runner, you know the importance of fueling up before you hit the streets or your favorite running trail.

What you should eat and drink to maximize your performance, though, is a mystery for many runners.

Should you load up on carbohydrates? Go heavy on the protein? Down sports drinks?

Here’s what runners should consider as they train.

Carbohydrates and running

The National Academy of Sports Medicine (ASCM) says athletes may have up to 40 percent greater energy needs than non-athletes. That means if you’re not eating the right foods, your performance could suffer.

Carbohydrates are an important part of any runner’s nutrition plan. Carbs are stored in your muscles as glycogen, which serves as long-term energy storage. Your body relies on glycogen when you exercise, and it’s important to keep your glycogen stores full so you don’t crash during a tough workout.

Eat before you work out, even if you don’t feel hungry, says The American College of Sports Medicine. About three to four hours before your workout, eat a meal of 300-600 calories that contains mostly carbohydrates, a moderate amount of protein, and a low amount of fat. Examples include toast with peanut butter, or a turkey sandwich with fruit.

The ACSM says endurance athletes, such as distance runners, should refuel every 45 to 60 minutes during a long workout, taking in 30 to 60 grams of carbohydrates (or 120-240 calories) each hour.  For shorter races or runs, it is not necessary to consume food during the race, but post-run replenishment is most efficient immediately after exercise.

Good foods to eat during a long exercise session include energy gels or beans, honey, bananas or oranges.

Eat your protein

Remember the importance of protein. It is the building block of your cells, and it’s especially important during the recovery process. Running and training breaks down cells. As you recover, those cells are repaired to make you better, faster and stronger — as long as the right ingredients, including protein, are available.

The ACSM recommends eating a post-workout snack of 300 to 400 calories containing a mix of carbs and protein. The carb-to-protein ratio should be 2:1 in short, low- to medium-intensity workouts, or 3:1 in long, high-intensity workouts.

Opt for low-fat, high-protein sources, such as beans, fish and poultry. Milk-based protein, like chocolate milk, is thought to be one of the best sources of protein post-workout.

Fats aren’t all bad

Fats, like carbs, provide energy. Healthy fats, such as polyunsaturated fats and monounsaturated fats, are part of a balanced diet. They should be at least 20 percent of your total fat intake, according to the ACSM.  Avocados are a good source, as well as nuts, olive oil, and salmon. Steer clear of saturated and trans fats, which can raise your cholesterol and lead to heart disease.

A few special micronutrients: Iron, vitamin D, and calcium

Long-distance runners are at high risk of iron-deficiency anemia. Low iron can result in decreased performance and a general feeling of tiredness. Your level of ferritin, a protein that stores iron, can determine if you need to take supplements. There is some debate over what is considered low, though 35 nanograms per millileter is often used as a minimum benchmark. You should talk to your doctor about the appropriate screenings for this.

Adding iron-rich foods, like beef, can help. Turkey, chicken and some fish also have lesser amounts of iron, which your body can best absorb alongside foods rich in vitamin C.

Vitamin D is crucial for bone health. Research has connected it to muscle strength, inflammation, and many other functions. Unfortunately, it is hard to get enough vitamin D, especially if you are wearing your sunscreen to protect your skin from the sun’s harmful rays. You can get your vitamin D level tested with a blood draw to determine if you need a supplement. Many doctors recommend taking 1,000 international units (IU) of vitamin D as a general rule.

Calcium is also an important ingredient for not only strong bones, but also muscle and nerve health. Getting 1,000 to 1,500 milligrams of calcium from food each day is best.

Hydration is important

Making sure you are drinking enough water is important for everyone, but it’s especially important for runners. Research shows that dehydration, even if it’s mild to moderate, can decrease performance. There is some debate about whether you should use thirst as an indicator to drink, or if you should drink water before thirst sets in. Current recommendations are to bring water along with you on runs that are longer than an hour, or longer than a 10K. The ACSM suggests drinking two to four ounces every 15 to 20 minutes.

It is possible to drink too much water during a long race, such as a marathon. In serious cases, you could develop hyponatremia, when your body has too much water and the level of sodium in the blood is too low.

For long runs, consider a sports drink. Not only do they give you an extra boost of carbohydrates, they also replace sodium that you lose while sweating. They are also a good choice for hydrating after a run longer than 60-90 minutes.

One last bit of advice: Don’t try any new foods or drinks on race day. You never know how your body might react, and that could be the difference between a great race and a bad one.

By choosing the right foods and making sure you are staying properly hydrated — both during training and on race day — you can have your best race ever.



Christina Morganti, MD, is an orthopedic surgeon at Anne Arundel Medical Center and avid long-distance runner. Dr. Morganti ran cross country and track at Brown University, and continues to compete in road races herself and run around cheering on her kids in their races.

She has run numerous marathons, including New York, Boston, and the Marine Corps Marathon. You can reach her practice, AAMC Orthopedics, at 410-268-8862.

Originally published Nov. 14, 2017. Last updated May 31, 2019.

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