The Importance of Carbohydrates and Electrolytes
When you run for an extended period, your body relies on stored carbohydrates, or glycogen, for energy. The body's glycogen stores can only sustain about 90 minutes of high-intensity running. Once these stores are depleted, your body must rely more on slower-burning fat stores, leading to a significant drop in pace and an overwhelming feeling of fatigue. This is where mid-run nutrition becomes critical. By consuming fast-digesting carbohydrates during your run, you can replenish your blood glucose and spare your muscle glycogen, delaying fatigue and improving your endurance.
Equally important is maintaining proper hydration and replacing lost electrolytes. Sweating during a long run depletes your body of essential minerals like sodium, potassium, and magnesium, which are crucial for muscle function and fluid balance. Neglecting electrolyte replacement can lead to muscle cramps, nausea, and dehydration, all of which will derail your performance.
Commercial vs. Real Food Fuel Options
Runners have a wide variety of options for mid-run fueling, falling broadly into two categories: commercial sports nutrition products and real food sources. Both have their advantages and require testing during training to ensure gut tolerance.
Commercial Fuel Options
These are engineered for convenience and digestibility. Energy gels provide a concentrated dose of fast-acting carbohydrates and are easy to consume on the go. Energy chews and gummies offer a more solid, chewable option for those who prefer to nibble. Sports drinks offer a combination of carbohydrates and electrolytes, helping to fuel and hydrate simultaneously. Modern formulations, like Maurten's hydrogels or SIS's isotonic gels, focus on different absorption mechanisms to minimize stomach distress.
Real Food Fuel Options
For runners who prefer a more natural approach or experience GI issues with synthetic products, real food can be an excellent alternative. These options should be low in fiber, fat, and protein for faster digestion during exercise. Popular choices include bananas, dates, raisins, and pretzels. Homemade options, such as energy bites made with oats, honey, and dried fruit, offer a customizable and cost-effective alternative. Sweet potato or rice cakes can also provide a steady release of carbohydrates.
How to Time Your Fueling Strategy
Optimal fueling is a matter of timing and practice. You should not wait until you feel fatigued to start fueling, as it's harder for your body to absorb nutrients effectively under stress.
- Start Early: Begin consuming fuel approximately 45-60 minutes into your run. This proactively tops up your energy stores before they become critically low.
- Frequent and Small Doses: Instead of taking a large amount at once, which can cause stomach upset, aim for smaller, more frequent doses. A good strategy is to consume a small amount of fuel every 20-30 minutes.
- Calculate Your Carbs: A general guideline for runs over 60 minutes is to consume 30-60 grams of carbohydrates per hour. For longer efforts (2.5 hours+), some athletes can train their gut to tolerate up to 90g per hour by using a glucose-fructose mix.
- Train Your Gut: Just as you train your muscles, you must train your digestive system. Practice your race-day fueling plan during your long training runs to discover what and how much you can comfortably consume without experiencing GI distress.
A Runner's Fueling Comparison Table
| Fuel Type | Pros | Cons | Carbs per Serving (Approx.) | Best For |
|---|---|---|---|---|
| Energy Gels | Portable, fast-digesting, convenient | Can cause GI distress in some, taste fatigue | 20-30g | Quick, concentrated energy on the go |
| Energy Chews | Easy to dose, palatable for some, chewable | Can be sticky, may require water | 30-40g | Runners who prefer to nibble vs. gulp |
| Sports Drinks | Combines hydration and carbs, balances electrolytes | Can be high in sugar, not all brands are equal | 30-60g per 500ml | Sustained hydration and energy |
| Bananas | Natural, readily available, provides potassium | Can be difficult to carry and digest on the move | 25-30g (large) | Slower pace or as part of a varied strategy |
| Dates / Raisins | Natural sugars, easy to carry | High in fiber for some, can be very sweet | 30g (~1 small box raisins) | A quick, natural sugar boost |
| Pretzels | Savory option, provides sodium | Can be dry and hard to chew, limited carbs | Varies based on brand | Runners craving salt, can help with hydration |
Practical Tips to Avoid GI Distress
Even with the right fuel, digestive issues are a common challenge for endurance runners. Here are some preventative tips:
- Minimize Fiber, Fat, and Protein: In the 2-3 hours before and during a long run, focus on low-fiber, low-fat foods. Fiber and fat slow down digestion, which can lead to cramping and stomach upset.
- Sip, Don't Chug: Avoid drinking large volumes of water or sports drink at once. This can lead to a sloshing feeling and overwhelm your digestive system. Take frequent, small sips instead.
- Train Your Gut: The best way to prevent issues is to practice your fueling strategy repeatedly in training. Don't try new fuels or timing on race day.
- Listen to Your Body: Learn to recognize early signs of digestive discomfort and adjust your intake accordingly. You may need to switch from a solid fuel to a liquid one or simply slow down for a few minutes.
Conclusion: Find What Works for You
Ultimately, there is no single "best" thing to eat during a long run. The best option is the one that provides your body with the fast-digesting carbohydrates it needs while sitting comfortably in your stomach. For most runners, this means a personalized combination of commercial and real food fuels, along with consistent hydration and electrolyte replacement. By practicing your fueling strategy during training, paying attention to your body's signals, and staying hydrated, you can confidently power through your longest runs. The key is to experiment, adapt, and refine your plan until you have a strategy that helps you perform your best.
For more information on the runner's diet, consider consulting resources like the Johns Hopkins Medicine guide: Runner's Diet | Johns Hopkins Medicine.
