Nutrient Timing: Pre-race Fueling Strategies for Endurance Athletes

Fueling for your race begins much sooner than you may think. Here are some quick tips to make sure you’re topped off and ready to perform!

Introduction

Endurance events, like cycling races or marathons, are as much a race as they are an eating competition. Failing to provide your body with adequate nutrition before and during a race can result in catastrophic “bonking.” Fueling for your events begins in the days leading up to the big day. So if you’re asking yourself “What are the best foods to eat before running” or “What should I eat before a marathon” you are in the right place! Below, I cover some simple tips and factors to keep in mind when planning your nutritional strategies.

Carb-loading: 24-48 Hours Pre-race

Meals before a race, let’s talk about them!

While many protocols exist for carbohydrate loading, studies have shown that 24-hour loading periods are just as effective as 5-7 day loading periods (Seebohar, 2005.) Traditionally, carbohydrate loading has been suggested to take place along a 5-7 day span. Contemporary studies have shown effective muscle and liver glycogen proliferation in the 24-hour window. This is why many endurance athletes opt for a large meal the night before their event. In short- carbohydrate loading 5-7 days before an event may be widely unnecessary.

Depending on the athlete, a 48-hour loading period may be warranted- especially if the athlete is on a lower-carb diet or is not used to pre-event carbohydrate loading. The reason for the longer loading phase? Digestion. Consuming a large amount of carbohydrates the night before an event could lead to a higher amount of water weight and just an overall sense of “over-fullness.” Don’t be worried, it takes a few races to figure out your groove. We are all different!

As such, 10k pre-race meals and 5k pre-race meals will look a little different.

Keep in mind that we are only covering carbohydrates in this article. Fluid, protein, and electrolyte intake are equally important during this period. Carbs will keep you fueled, and electrolytes and fluid will keep you in the fight.

For endurance events, aim to consume 7 grams of carbs per every kilogram of body weight. For example, a 60kg athlete would consume 420 grams of carbohydrates during a 24-48 hour window before an event. This amount is roughly 1,680 calories (Atkinson et al., 2011.)

Race Day Nutrition: 1-3 Hours Pre-race

Many athletes have a set race-day ritual when addressing nutritional strategies for maximal performance. Anecdotally, my ritual is to pop an energy gel right before the gun goes off. This gives me a quick rush of carbohydrates, amino acids, and caffeine. Others may choose to down a Red Bull and some gummy bears right before, hey if that works for you, then awesome!

Gels or liquids?

This topic has been researched into oblivion. During my review of several publications, I found that no differences in performance outcomes have been observed following the ingestion of solid vs. liquid carbohydrates. A lot of this depends on what an athlete can handle in terms of GI stress. Simply put: marathon runners may prefer something lighter before an event versus a cyclist who has less “jostling” of the intestines during their event.

Similarly, carbohydrates ingested 30 minutes before exercise results in better performance than 120 minutes before exercise (Rothschild et al., 2020.)

Looking for snacks to eat before running? Check out my 3 quick and easy meals for endurance athletes!

Ingestion of carbohydrates 3-4 hours before exercise can increase liver and muscle glycogen stores and has been associated with enhanced endurance exercise performance (Hargreaves, 2001.) It is interesting to note, that, some studies may suggest a paradoxical hypoglycemia following ingestion of pre-race carbohydrates however, there exists no compelling evidence that this transient form of hypoglycemia affects performance.

Regardless of your race-day breakfast, steer away from consuming fiber, as this will slow gastric emptying and delay the uptake of glucose by your skeletal muscle cells. Yep, that’s right… fiber can be bad for you. (Only in this case; otherwise, fiber is AMAZING and we should all aim to get enough in our diet.

Conclusion

So what should I eat before a marathon? I am sorry to break the news to you: there is no “magical” amount of carbohydrates that you should consume before a race- it will take time and experimentation to determine which is best for you. Good foods to eat before running or cycling will look different for everyone. Working with different foods, like energy gels or carb-bottle mixes, will help you determine how reactive your GI system is during an event. This is best done during the off-season or pre-season- as it will take some time for your gut to get onboard! I’d love to work 1:1 with you on your endurance nutrition! Apply to work with me today!

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Discover the ultimate guide to fueling your run with the best food choices! Explore a variety of options for the perfect pre-run meal, including snacks and meals tailored for both 5k and 10k races. Learn about the top foods to eat before running, ensuring optimal energy levels and performance. Whether you're gearing up for a marathon or a quick jog, find expert advice on the best pre-run meals and discover the key to peak performance. Elevate your running experience with the right nutrition – because what you eat before a run matters!

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References

Atkinson, G., Taylor, C. E., Morgan, N., Ormond, L. R., & Wallis, G. A. (2011). Pre-Race Dietary Carbohydrate Intake Can Independently Influence Sub-Elite Marathon Running Performance. International Journal of Sports Medicine, 32(8), 611–617. https://doi.org/10.1055/s-0031-1273739

Hargreaves, M. (2001). Pre-exercise nutritional strategies: Effects on metabolism and performance. Canadian Journal of Applied Physiology-Revue Canadienne De Physiologie Appliquee, 26, 64–70. https://doi.org/10.1139/h2001-043

Rothschild, J. M., Rothschild, J., Andrew E. Kilding, Kilding, A. E., Daniel J. Plews, & Plews, D. J. (2020). What Should I Eat before Exercise? Pre-Exercise Nutrition and the Response to Endurance Exercise: Current Prospective and Future Directions. Nutrients, 12(11), 3473. https://doi.org/10.3390/nu12113473

Seebohar, B. (2005). Nutrition Periodization for Endurance Athletes: Taking Traditional Sports Nutrition to the Next Level.