Best and Worst Pre-Run Foods

How to Avoid Runner's Trots

Peanut Butter on Toast

It's important to eat before running to make sure you're properly fueled. But if you've had issues with gastrointestinal distress (also known as runner's trots) during or after your runs, the foods you're eating in the 24 hours before your runs may be the culprit. Here's a guide to what you should and shouldn't eat before your runs.

Foods to Avoid Before Running

Try limiting or eliminating some of these foods before running to see if it makes a difference:

High-fiber foods: Whole-grain foods, vegetables, legumes, and fruits that are high in fiber can cause gastrointestinal distress or diarrhea. While those foods are excellent and healthy food choices for runners, they may cause digestive issues in runners who consume them the night before or morning of a long run. So, while you shouldn't eliminate those healthy options from your diet, you're probably better off eating them when you don't have a long run the next day.

High-fat foods: Foods with a lot of fat -- such as fried foods, cheese, hamburgers, or bacon -- digest slowly and will feel like they're sitting in your stomach.

Caffeine: Coffee or other caffeinated beverages can cause stomach issues or diarrhea. (Although some runners, especially regular coffee drinkers, can tolerate it without problems.)

Safe Pre-run Foods

These are the best types of pre-run foods to help avoid gastrointestinal distress during or after running:

Refined Carbs: Processed white foods, like regular pasta, white rice, and plain bagels are good choices. Although they're not as nutritious as whole grain and unprocessed foods, they're easier on your stomach because the whole grain is already broken down. A plain bagel with some peanut butter (and a glass of water) would be a safe choice before a long run.

Low-Fiber Fruits and Veggies: If you really want to eat fruits or vegetables before runs, zucchini, tomatoes, olives, grapes, and grapefruit are all low in fiber.

Safe Dairy: Some people have issues when they consume dairy products before runs. Soy, rice, and almond milks are generally safe because they don't contain the sugar lactose, which can be tough to digest. You can also try acidophilus milk and yogurts with live cultures, which contain bacteria that help with digestion.

Timing of Foods is Key

Whenever possible, it's best to finish eating a meal 4 to 6 hours before exercise. Doing so will help you minimize gastrointestinal issues and optimize your performance. The food will already be digested and absorbed, and your muscle and liver glycogen stores will be at their highest. If you're running in the morning, that would mean eating a nutritious carbohydrate-rich meal before going to bed. If you're hungry and need an additional snack before your run, choose a small, carb- and protein-containing snack and eat it 30 to 60 minutes before.

Nothing New on Race Day

If you're training for a big race, such as a half and full marathon, it's important that you figure out what foods work for you before race day.

You don't want to eat a new breakfast food the morning of your race because you never know how it will affect you. Your training runs, especially your long runs, are the time to try different foods and figure out what works best for you. Every runner is different, so what works for someone else may not necessarily work for you. Experiment with different foods the night before and morning of long runs and pay attention to how you feel during the run. Once you've figured out foods that don't cause you any GI issues and seem to help you achieve optimal performance, stick with those choices.


Muth, Natalie, M.D. Sports Nutrition for Health Professionals, 2015