For runners, the right fuel is crucial, but what you choose to eat—and when—is just as important as what you choose to avoid. The wrong food choices can lead to uncomfortable and performance-limiting issues like cramping, bloating, and urgent bathroom stops. This guide explains the key food types to sidestep and provides actionable advice for better fueling.
High-Fiber Foods
While fiber is a vital part of a healthy diet, consuming large amounts right before or during a run is a recipe for gastrointestinal trouble. The body struggles to digest high-fiber foods quickly while simultaneously directing blood flow away from the gut to the working leg muscles. This can cause gas, bloating, and diarrhea, commonly known as 'runner's trots'.
Examples of high-fiber foods to limit pre-run:
- Beans and lentils
- High-fiber cereals and bran
- Cruciferous vegetables like broccoli, cauliflower, and cabbage
- Whole grains, including whole-wheat pasta and bread
- Apples, pears, and other high-fiber fruits
The Solution: Save these nutrient-dense foods for post-run recovery or rest days when your digestive system is not under stress. Before a run, opt for low-fiber, easily digestible carbohydrates like white rice, white bread, or a banana.
Fatty and Fried Foods
High-fat foods are digested very slowly, which can make you feel sluggish and heavy during a run. Your body expends more energy on digestion, diverting resources that should be used to power your muscles. Fried foods are particularly problematic, often containing high levels of unhealthy saturated fats that can also contribute to inflammation.
Why fat can be a problem pre-run:
- Slow Digestion: High-fat meals can sit in your stomach for hours, leading to cramps and discomfort.
- Sluggishness: The body's focus on digestion can leave you feeling heavy and less energetic.
- Heartburn: Greasy foods can also trigger acid reflux for some individuals, which is highly unpleasant when running.
The Solution: While healthy fats are essential for a runner's overall diet, they should be consumed in moderation and not immediately before a run. Opt for lean protein sources and healthy carbs in your pre-run meals and save the burger and fries for your post-race celebration.
Spicy Foods
For some runners, spicy foods can irritate the gastrointestinal tract, leading to heartburn, indigestion, and even diarrhea. The compound capsaicin, which gives chili peppers their heat, can be an irritant to the stomach and intestines. The discomfort can be amplified by the physical jarring motion of running.
The Solution: Experiment with milder flavors in the 24 hours leading up to a long run or race. Stick to familiar, bland-to-moderate meals that you know your stomach can handle. Save the spicy curries and Mexican dishes for a day off.
Sugary Drinks and Artificial Sweeteners
Reaching for a sugary soda or energy drink for a quick boost is a common mistake. The high sugar content can cause a rapid spike and subsequent crash in blood sugar levels, leaving you feeling more fatigued than before. Many diet and sugar-free products contain artificial sweeteners like sorbitol, which can have a laxative effect and cause significant gastrointestinal distress, including bloating and diarrhea.
The Solution: For pre-run fueling, choose natural, easily digestible carbohydrate sources like dates, bananas, or a purpose-made sports gel for concentrated energy. Hydrate with water or a properly formulated electrolyte drink that avoids high concentrations of simple sugars or artificial sweeteners.
Dairy Products
Lactose intolerance is more common than many people realize and can be particularly troublesome for runners. Consuming dairy products like milk, cheese, and yogurt before a run can cause cramping, gas, and an upset stomach, especially for those with an undiagnosed sensitivity. The strenuous nature of running can exacerbate these symptoms.
The Solution: If you suspect dairy is causing you problems, try a plant-based alternative like almond, oat, or soy milk. Experiment with your diet during training to see if eliminating dairy helps resolve your stomach issues. A food diary can be a great tool for identifying triggers.
Comparison Table: Pre-Run Food Choices
| Food Type | Worst Pre-Run Choices | Best Pre-Run Alternatives |
|---|---|---|
| Carbohydrates | High-fiber whole grains (oatmeal, brown rice) | Simple, easily digestible carbs (white toast, banana) |
| Proteins | Red meat, heavy chili with beans | Small amounts of lean protein (turkey on white bread) |
| Fats | Fried foods, heavy sauces, large amounts of nuts | Trace amounts in toast with nut butter (allow for digestion) |
| Liquids | Sugary sodas, energy drinks, alcohol | Water, electrolyte drinks, watered-down juice |
| Other | Spicy sauces, artificial sweeteners | Bland, familiar foods you have tested in training |
The Timing of Your Meals
Just as important as what you eat is when you eat it. Timing is key to allowing for proper digestion without feeling heavy or hungry.
- 2-4 hours before: A full meal that is predominantly carbohydrates, with some lean protein and low-fiber options, is ideal for longer runs. Examples include a bagel with peanut butter, oatmeal with banana, or a simple pasta dish.
- 30-60 minutes before: If you need a quick energy top-up, stick to a small, simple carbohydrate snack. A banana, a couple of dates, or a small handful of pretzels can provide a quick boost without upsetting your stomach.
- Never on race day: Do not experiment with new foods on race day. Stick to what you've practiced during your training to avoid any surprises.
Conclusion
Optimizing your nutrition is a powerful tool for improving your running performance and making your miles more comfortable. By paying attention to what foods should runners avoid, especially before a run, you can prevent common and frustrating gastrointestinal problems. Remember that while high-fiber, healthy fats, and proteins are vital for overall health, their timing is critical for runners. Practice your fueling strategy during training, listen to your body's signals, and you'll be well on your way to more enjoyable and successful runs.
For more detailed information on a runner's diet, consider consulting authoritative sources like Johns Hopkins Medicine for expert advice.
