10 Foods To Avoid Before a Run

In an ideal world, every runner would have access to a banana, avocado with sea salt, or a piece of warm toast with jam before a run. Alas, life gets crazy, and there’s not always time to visit the grocery store for a perfect pre-run snack. 

Skipping a meal is out of the question: running on a body depleted of glycogen will cause mental and muscle fatigue. But running on a stomach full of hard-to-digest food can lead to cramps, gas, blood sugar variations, and sluggishness. In fact, a pre-workout snack can make or break a run.

Running nutrition is complex. There is no such thing as “the best diet for runners.” Everybody is different, and it’s only through trial-and-error that a runner learns what serves them best. The foods listed below are often bothersome to the general population. Yet, they may not affect some athletes. Use this list as an educational guide to crafting your own pre-run snack – even if it seems totally random!

1. Bell Peppers and Cucumbers

Bell peppers and cucumbers dipped in hummus are a delicious and nutritious snack for runners. However, it’s best reserved for after a run, rather than before. The skin of these foods is extremely dense and fibrous, making it difficult for the body to break down. A study by the National Library of Medicine (NLM) estimated that 23% of runners avoid high-fiber foods. It can take hours for the body to properly absorb a pepper. Any heavy plant matter in the gut during a run can cause indigestion or acid reflux. 

Do not despair, bell pepper and cucumber fiends! Cooking these plants helps loosen up the outer skin, making it easier to digest. Pepper-lovers should try grilling their peppers and eating them with a hard cheese, like halloumi, to dull and counteract the acidity. Skinning the cucumber also helps. Still craving a crunch? Sprinkle sesame seeds on top!

whole red bell peppers

2. Meats

Animal meats are a natural source of amino acids and protein. Red meat, white meat, and seafood are all sources of valuable nutrition. While the exact amount of red meat required for healthy nutrition is debatable, the NLM found that its health benefits provide a variety of nutritional needs. 

medium rare steak with salt, pepper and rosemary

But, animal-based protein can be heavy in the gut. Many runners experience bloating, gas, and irritation in their gastrointestinal tract after eating meat. Some runners experience irritation 2-3 hours afterwards. To be on the safe side, eat meat long before a run or immediately after.

3. Tomatoes

Tomatoes are packed with nutrients that runners need, like vitamin C, K, and potassium. Many studies, summarized here by Frontiers in Nutrition, have also linked tomatoes to increased cardiovascular health. But, they’re not the best pre-run snack because they also contain high levels of malic and citric acid. Higher levels of acid in the system can cause acid reflux and similar burning sensations.

Luckily, there are some ways to calm down the acidity of tomatoes. Try eating tomatoes on toast with butter or oil (fatty foods help to offset the effects of acidity). Adding a bit of baking soda to a tomato sauce also helps increase the pH level (which helps with the burning sensation of gastro-intestinal acid).

globe tomatoes on the vine

4. Legumes

Legumes, like beans or lentils, are an ideal source of fiber for runners. A study by Aspetar Sports Science shows that both plant-based and animal-derived diets can positively impact sports performance. However, eating high-fiber foods before a run can lead to gastrointestinal distress or diarrhea. The good news: there are ways to limit the gas-inducing qualities of beans. 

pinto beans in cast iron skillet

First, buy raw beans and soak them before cooking (the amount of soaking time varies by bean). Second, if you do eat beans before a run, combine them with plain ol’ water for easier digestion. Third, combine the beans with natural digestive enzymes (like sauerkraut) or take a probiotic supplement.* 

*A note on supplements: excessive supplements can be dangerous, so always consult a physician before adding one to your diet.

5. Simple Carbohydrates

The body uses carbohydrates first as fuel for running and exercise; they provide stamina for running (see Figure 1 in this Strength and Conditioning Journal article regarding the interplay of fat and carbohydrate use in marathoners). There is no such thing as “good carbohydrates” and “bad carbohydrates.” There are carbohydrates that are more nutrient-dense and therefore a longer-lasting fuel source. These are called complex carbohydrates.

Alternatively, there are carbohydrates that are higher in sugar, more easily digested, and less nutritious. These are called simple carbohydrates. For example, a slice of seeded bread is a more complex carbohydrate than a slice of plain white toast. 

moist sugar cookies

While running, the body is happy to use any carbohydrate that it can get. But, a simple carbohydrate does not contain the same “staying power” as a complex one. Sugary carbohydrates in particular will cause an initial spike and then a heavy drop in blood-glucose levels. The body and mind will feel sluggish when glycogen stores are depleted. 

On longer runs, lack of blood sugar may also cause exercise-induced hypoglycemia. A hypoglycemic runner will suffer from fatigue, headaches, and performance loss. When left untreated, hypoglycemia is extremely dangerous. (Learn how to spot signs of exercise-induced hypoglycemia in this Medical News Today article).

The bottom line: carbohydrates are the best thing to eat before a run. If there are no complex carbs available, then a slice of white toast is better than nothing. Better choices are nutrient-dense sources of carbohydrates like oatmeal and quinoa. Or, simply pair that white toast with peanut butter, bananas, and honey, or some slices of cheese to bump up the nutritional value.

6. Fatty Foods

Fat, the macronutrient, is an essential part of life. All humans need fat, protein, and carbohydrates to function. But, super fatty foods are best avoided before a run. Fat requires more work and time for the body to digest. The benefit to pre-run fat intake is longevity: fats power athletes longer. 

But, eating a fat-filled snack RIGHT before a run will not allow the body enough time to convert the food into usable nutrition. Plus, fats can cause some serious abdominal discomfort when not properly digested before movement. Some runners find that foods high in saturated fats (like cheese, bacon, burgers, etc.) are particularly irksome.

Hot, gooey pepperoni pizza slice


When eating fatty foods before a run, try the following hacks: 

  • Choose natural sources of fat like nuts and avocados
  • Eat fat at least one hour before commencing a run
  • Eat fats that naturally have high water content, like mozzarella

7. Protein Bars

Protein bars are awesome fuel for fitness – they’re often low in sugar, high in added vitamins and minerals, and extremely accessible for busy runners. In a bind, a protein bar before a run is a fine choice. But the better choice is a carbohydrate-focused energy bar, like a muesli bar or granola bar.

Why? Our bodies require carbohydrates to fuel exercise. After the exercise is complete, the body needs protein to rebuild muscles. Eating a high-protein snack after a workout and a high-carb snack before a workout will power a workout best. 

Rather than buying expensive pre-packaged bars, try making homemade granola bars.

8. Lactose

Not all runners can handle a glass of milk or a cup of yogurt before a workout. The culprit: lactose, which is a naturally-occurring digestive irritant for many folks. But that doesn’t mean that cheeses and milk need to be eliminated from the diet on run days. In fact, lactose is a great source of fuel for some runners (see this My Sport Science analysis of the carbohydrate properties in lactose). It’s the timing that counts!

pouring whole milk

Instead, choose lower-lactose dairy products like goat’s cheese and probiotic yogurts. Or, choose delicious dairy alternatives like hemp milk and soy milk. Here’s a recipe for a creamy apple porridge that uses alternative milk.

9. Spicy Foods

As tasty as a bowl of curry or chili is, spicy foods are a bad idea before running. Many spices can cause heartburn and gastrointestinal distress. Avoid urgent stops at the rest station toilet by eating bland foods before a run and spicy foods after. (For those lovers of spice, it’s worth noting that a more regular intake of spice creates higher gut tolerance. Eat more spice in your diet and it’s less likely to cause issues during your run.)

dried red pepper chili flakes

10. Sports Drinks

While sports drinks are a great option for longer workouts or multiple workouts per day, they’re not necessary for runners who drink water regularly and eat a balanced diet. Isotonic drinks are best used when running for an hour or more. The healthiest diet is one that garners minerals and nutrients through food, not supplements. Moreover, many common sports drinks are loaded with sugars, which can cause blood sugar to drop precipitously mid-run.

Yes…drinking plain water is best for the average runner, but also very boring. Add extra oomph to H20 with these at-home sports drink recipes.


The bottom line: runners who eat before a run provide their bodies with the energy to push through a challenge. Eating before a run is always a good idea, but some foods can cause unnecessary irritation, limiting overall performance. Use the list above to craft feel-good pre-run snacks that perfectly suit your individual running needs.

Let’s see it! Make a snack, take a photo, and then go for a run and let us know how it went. Capture the moment and tag us on social: @adidasRuntastic. We can’t wait to see you and your recipe in-action!

Want to learn what to eat before running? Find out more about the 9 best foods to boost your running performance.


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