Why Runners Hit the Wall
Every runner eventually meets “the wall,” that mile where your legs feel like sandbags and your pace falls apart for no clear reason. Sports nutrition researchers have studied this for decades, and it usually comes down to carbohydrates more than willpower. What matters is whether you have enough carbs available and whether the food you eat around a run is easy to digest while you’re moving. That’s also what separates the best energy bars for runners from everything else on the shelf.
Carbs Are Your Main Fuel
During a long run, carbohydrates supply most of your energy. Your body stores carbs in your muscles as glycogen, and once those stores run low, your performance drops, even if you’ve eaten enough calories overall.
Studies of ultramarathon runners show how directly this plays out. In a 100-mile race, runners who took in more carbs during the event tended to finish faster. In a separate 120 km race, the stronger finishers kept their carb intake steady hour by hour, while the runners who slowed down let theirs slip.
Current sports nutrition guidance suggests 30 to 90 grams of carbohydrate per hour for runs longer than 60 to 90 minutes, with longer efforts at the higher end. Real-world data from ultra events shows most athletes eat somewhere between 22 and 63 grams an hour, which often falls short of those targets.
Why Some Bars Cause Stomach Trouble
Not every carb source sits well mid-run. Stomach and gut problems are one of the most common reasons runners underperform in endurance events, and research has linked them to a few specific factors: high fiber, high fat, high protein, and very concentrated carb drinks, especially at higher intensities and longer distances. In one survey of endurance runners, high-fiber and high-protein foods were among the foods people most often skipped before a run for exactly this reason.
That’s useful to know when you’re picking a snack. A bar packed with fiber or fat can look healthy on the label and still sit heavy once you start moving. Many long lasting energy bars lean on fat and fiber to keep you full, which works well at your desk but can backfire at mile eight. For eating close to or during a run, simpler whole-food carbs usually go down easier.
How to Choose (and Time) Your Bar
- Pick bars that lead with carbs. Whole-food carb sources like dates tend to digest more predictably during exercise than high-fiber or high-fat options.
- Save fat and fiber for later. Eat fiber-rich, higher-fat snacks well before or after your run, when your stomach isn’t competing with your working muscles for blood flow.
- Train your gut along with your legs. Tolerance varies from person to person and improves with practice, so try your race-day fuel on training runs first instead of meeting it for the first time on race morning.
- Plan for recovery, too. Guidance for endurance athletes suggests about 1.0 to 1.2 grams of carbohydrate per kilogram of body weight per hour for the first four hours after a long run. For a 150-pound runner, that’s roughly 70 to 80 grams of carbs an hour, so a post-run bar is a good start alongside a real meal.
Where ILA Bars Fit
ILA bars are made from whole foods like nut butter, dates, and hemp seed, with just 2 to 3 grams of fiber per bar. With 12 to 13 grams of fat and 9 grams of plant protein, they work best as a snack around your run, before to top off your energy stores or after as part of recovery.
The bars are also made without oats, which helps if you’re managing an oat sensitivity and still want a whole-food option.
ILA bars also include Ashwagandha and Reishi, two herbs that come up often in conversations about adaptogens for endurance athletes. Herbalists have long used Ashwagandha to help the body adapt to daily demands, and some research suggests it may support endurance in active people, which matters when you’re thinking about how a whole training week feels.
Fueling Your Next Long Run
Carbs drive endurance performance, and how those carbs are packaged decides whether they fuel you or send you looking for a porta-potty at mile six. The best energy bars for runners are built on simple whole-food carbs and go easy on fiber and fat when you’re eating close to a run. Test your options on training days and you’ll show up to race day knowing what your stomach can handle.
REFERENCES:
- “Prioritizing Carbohydrates: A Guide for Endurance Runners.” Utah State University Extension. https://extension.usu.edu/nutrition/research/prioritizing-carbohydrates-a-guide-for-endurance-runners
- “A comparative observational study of carbohydrate intake and continuous blood glucose levels in relation to performance in ultramarathon.” PMC, National Institutes of Health. https://pmc.ncbi.nlm.nih.gov/articles/PMC10784534/
- “Real-Time Observations of Food and Fluid Timing During a 120 km Ultramarathon.” PMC, National Institutes of Health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946582/
- “Nutritional Recommendations To Avoid Gastrointestinal Distress During Exercise.” Gatorade Sports Science Institute. https://www.gssiweb.org/sports-science-exchange/article/sse-114-nutritional-recommendations-to-avoid-gastrointestinal-distress-during-exercise
- “Dietary restrictions in endurance runners to mitigate exercise-induced gastrointestinal symptoms.” Journal of the International Society of Sports Nutrition, Springer Nature. https://link.springer.com/article/10.1186/s12970-020-00361-w
- Komorowski, M., et al. “The Role of Ashwagandha in Exercise Performance and Recovery: An Evidence-Based Review.” Quality in Sport, 2025. https://apcz.umk.pl/QS/article/view/61525