The Worst Foods To Eat Before A Run, According To Running Coaches

It’s the number one feeling runners dread: You’re in the middle of crushing some miles when all of a sudden, your stomach starts cramping and you know that you need to find a bathroom ASAP. Running speeds up the digestive system, and what you ate (or drank) before you laced up your sneakers can work for or against you. 

To ensure that what you consume is used to fuel your body without any unpleasant side effects, it’s important to be mindful of what you eat (and drink) directly before your run ― and also the night before. Want to make sure you do it the right way? Keep reading for advice straight from professional runners themselves. 

What to avoid the night before a run.

If you have a race or long run coming up, certified triathlon coach and certified personal trainer Kristen Hislop advises you should start being conscious of what you’re eating a couple of days out. Her advice is to start decreasing your fiber intake. Yes, fiber is an important and crucial nutrient — and you shouldn’t nix it from your diet completely — but Hislop says that high-fiber foods like Brussels sprouts, cabbage, lentils and whole grains require a lot of work for the digestive system to break down, and you want to make life as easy as possible for your digestive system in the days leading up to and on the day of your long run.

Hislop also says fatty foods take longer to digest, so it’s a good idea to skip foods like pizza, burgers and french fries. The key, she said, is giving your body something easy to digest and to use for fuel (like white rice, potatoes and pasta) with a protein source you know your body digests well.

The night before a race or long run, carb-loading is on many runners’ minds. Thinking about whipping up some spaghetti and tomato sauce? You might want to rethink your choice. “Everyone thinks about pasta before running and often that comes with tomato sauce, but tomatoes are very acidic and can cause heartburn,” Hislop said. Top your pasta with olive oil or butter instead. 

Registered dietitian and running coach Cortney Berling points out that spicy foods can also cause heartburn for many people, so that’s another type of food runners may want to avoid the night before.

There’s something else to avoid the night before your long run: alcohol. Not only can it irritate the gut the next day, but running coach and certified personal trainer Nicole DeSena says it can contribute to dehydration and lead to fatigue during your run. Save the booze until after you cross that finish line.

What to avoid the morning of your run.

Whether you have a long run on the books as part of your training or it’s race day, it’s likely your run is going to be in the morning. There are several foods and drinks that Elyse Kopecky — nutrition coach and co-author of “Run Fast. Eat Slow.” — absolutely avoids in the morning, and she recommends other runners do, too.

Most importantly, she says to avoid eating or drinking anything new. Now is not the time to experiment, even if it’s something a fellow runner recommended to you. Race coach and certified personal trainer Whitney Biaggi agrees, saying, “Since food can affect everyone differently, it’s important to test any fueling plan, especially what you eat pre-run, prior to race day, ideally during training runs.”

Similar to how Hislop recommends avoiding high-fiber foods a couple of days before your long run, Biaggi says they’re not ideal to eat the morning of your run, either. “Generally, highly fibrous foods can often cause abdominal issues, which can mean additional bathroom stops and discomfort,” she said. Kopecky agrees, saying to watch out for protein bars or powders with inulin fiber, which often comes in the form of chicory root. While we’re on the subject of protein bars and powders, she says to also keep an eye out for sorbitol, a sugar alcohol that can irritate the gut and cause diarrhea.

DeSena also recommends avoiding dairy, including yogurt and dairy-based smoothies. She says that, in general, most people do not tolerate dairy well before a long run and it takes a while for the body to digest it. 

Curious if it’s still OK to have a cup of coffee before your run? All the experts say this really comes down to the individual; some people find that coffee actually enhances their run, giving them an extra push, while others experience stomach issues. Hislop says the key is to test it out when the stakes are lower (like a much shorter run) to see how it affects you. 

What to eat instead.

Now that you know everything to avoid the night before and morning of your run, it’s time to figure out what to eat. And it is important to eat, by the way. “You should fuel up before any race or run,” Berling said.

All five running coaches recommend focusing on one type of food: simple carbohydrates. “Eat simple, easy-to-digest carbs 30 to 60 minutes before your run,” Berling said, adding that 30 grams of carbs before runs that are 30 to 60 minutes long is a good barometer to go by, increasing the amount as necessary for longer runs. Examples of simple carb breakfasts include a bagel, white bread toast, English muffin or plain rice cakes.

Lastly, DeSena and Biaggi say to remember to hydrate. Start drinking water two hours before your run as opposed to downing a big glass right before you start to avoid feeling weighed down or having to pee soon after starting. 

To sum it all up, the big thing to keep in mind before a long run is to give your body fuel that’s easy to digest, and that means simple carbohydrates. Avoid high-fiber or fatty foods, which require the digestive system to work harder to break them down, and keep an eye out for sorbitol, which can irritate the gut.

With these guidelines in place, you won’t have to worry about your stomach distracting you from your run. Instead, you can think about all the delicious food you’ll be enjoying after.