Fueling for distance runners generally centers around ensuring you have enough carbohydrates in your pre-workout meal or snack to keep blood glucose levels high and glycogen stores sufficient for long-distance training sessions.
But, what are the best foods to eat before long runs for marathon training or half marathon training plans?
In this guide to what to eat before a long run, we will discuss the importance of carbs for high-intensity exercise, the best foods for distance runners to eat before long-distance workouts, and other tips for creating a fueling strategy for longer training sessions.
How Do You Fuel Up For a Long Run?
According to research, during exercise at intensities greater than approximately 60% of your VO2 max, blood glucose and muscle glycogen are the primary fuels being oxidized to produce the necessary ATP for your muscles because carbohydrates can be oxidized for energy much quicker than fats.1Hawley, J. A., & Leckey, J. J. (2015). Carbohydrate Dependence during Prolonged, Intense Endurance Exercise. Sports Medicine, 45(S1), 5–12. https://doi.org/10.1007/s40279-015-0400-1
Therefore, even for long-distance runs, the primary fuel source for your muscles is carbohydrates.
According to the Academy of Nutrition and Dietetics, an endurance-trained athlete (such as runners in marathon training or half marathon training) can store up to 1,800 to 2,000 calories of fuel as glycogen in the muscles and liver, though smaller runners might store closer to 1,500 calories or so.
Depending on your body size and running pace, this means that you might store enough glycogen to support about 90-120 minutes of running at your marathon race pace effort or 75 100 minutes at half marathon pace.
If you don’t eat enough carbohydrates before your longer training runs—particularly for morning runs— you will start the workout in a state where your muscle glycogen and liver glycogen stores are already partially depleted.2Ludwig, D. S., Hu, F. B., Tappy, L., & Brand-Miller, J. (2018). Dietary carbohydrates: role of quality and quantity in chronic disease. BMJ, 361, k2340. https://doi.org/10.1136/bmj.k2340
This can result in the dreaded experience of “bonking” or “hitting the wall,” which occurs when your body has insufficient glycogen to break down into glucose for your muscle cells.
As a result, the muscles have to oxidize fat for fuel.
It takes significantly longer to metabolize fat and generate ATP for use during exercise compared to breaking down glycogen or using glucose from stored or recently consumed carbohydrates.
Because the metabolic process to generate energy from fat is significantly slower, it becomes impossible to sustain high-intensity exercise, as the rate that ATP is produced through the slower energy production pathways.
They cannot keep up with the rate at which your muscle fibers need a fuel source to break down for energy.
As a result, you have to run slower or significantly decrease the intensity, which can cause you to feel sluggish and unable to maintain your goal race piece or goal training pace.
This is why distance runners who follow a low-carb diet or try to do a longer training run on an empty stomach may struggle to get through a long run or high-intensity workout.
When you try to do a morning run on an empty stomach, you are already starting in a glycogen-depleted state, as your brain, red blood cells, and certain other cells of your body burn through glycogen during the overnight fast.
This means that you are already starting in a deficit relative to the potential maximum glycogen storage, which in and of itself may be insufficient for marathon training long runs or certainly the full marathon distance on race day.
Do I Need to Eat a Lot of Carbs Before a Long Run?
Carb loading, also called carbohydrate loading, is a sports nutrition strategy3Nakatani, A., Han, D.-H., Hansen, P. A., Nolte, L. A., Host, H. H., Hickner, R. C., & Holloszy, J. O. (1997). Effect of endurance exercise training on muscle glycogen supercompensation in rats. Journal of Applied Physiology, 82(2), 711–715. https://doi.org/10.1152/jappl.1997.82.2.711 that some marathon runners, triathletes, and endurance athletes use to increase muscle glycogen storage above normal levels to prevent bonking on race day or during long training runs.4Jensen, R., Ørtenblad, N., Stausholm, M. H., Skjærbæk, M. C., Larsen, D. N., Hansen, M., Holmberg, H., Plomgaard, P., & Nielsen, J. (2021). Glycogen supercompensation is due to increased number, not size, of glycogen particles in human skeletal muscle. Experimental Physiology. https://doi.org/10.1113/ep089317
Carb loading protocols involve depleting your glycogen stores by following a very low-carbohydrate diet for 2-3 days (coupled with a high-intensity workout to deplete glycogen) and then following a very high-carbohydrate diet for 2-3 days leading up to race day.
According to the Mayo Clinic, marathon runners who want to do pre-run carb loading should aim for 8-12 grams of carbohydrates per kilogram of body weight for 1-3 days before the long-distance training session or race day.5Mayo Clinic. (2022, March 22). Carbohydrates: How carbs fit into a healthy diet. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/carbohydrates/art-20045705
Keep in mind that carbohydrate loading is generally not necessary during your training program for regular long runs for half marathon training or marathon training. In fact, eating too many carbs can cause bloating and GI upset and make you feel sluggish.
However, if you are training for an ultramarathon or a long-distance triathlon, you may want to do modified carb loading before some of your key long training sessions.
As a running coach, I also recommend that marathon runners try carb loading before the longest long run up on the training plan if they intend to use this nutrition strategy going into race day.
This will ensure you don’t have any GI upset from an excessive carbohydrate intake or eating the wrong foods (high-fiber, certain veggies, high-fat foods, too much dairy, too many simple carbs).
What to eat the night before a long run will depend on how far you are running, but you should eat a dinner high in complex carbohydrates to ensure that your glycogen stores are fully topped off before the overnight fast, along with lean protein and healthy fats.
What Should I Eat Before a Long Run?
The best foods to eat before a long run depend on several factors, such as:
- The time of day (morning run vs afternoon or evening run)
- How fast you will be running (high intensity vs easy runs)
- How long you are running
- Your body size
- How sensitive your digestive system is (whether you are prone to GI issues, bloating, diarrhea, etc.)
- How long before the long-distance workout you are eating your pre-run meal or pre-run snack
The general recommendations for the timing of eating before running are as follows:6Kerksick, C. M., Arent, S., Schoenfeld, B. J., Stout, J. R., Campbell, B., Wilborn, C. D., Taylor, L., Kalman, D., Smith-Ryan, A. E., Kreider, R. B., Willoughby, D., Arciero, P. J., VanDusseldorp, T. A., Ormsbee, M. J., Wildman, R., Greenwood, M., Ziegenfuss, T. N., Aragon, A. A., & Antonio, J. (2017). International society of sports nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 14(1). https://doi.org/10.1186/s12970-017-0189-4
- Wait 3-4 hours after a large meal to run
- Wait 2-3 hours after a small meal to run
- Wait 1-2 hours after a snack to run
- Wait 30 minutes after an energy gel or fruit juice to run
The closer it is before your workout, the more important it becomes to eat just simple carbs that digest quickly and easily.
For example, a marathon runner having a pre-run breakfast 2-3 hours before a long-distance workout can choose whole foods with complex carbohydrates and a little bit of protein and healthy fats (such as whole wheat toast with peanut butter).
Whereas if there is only one hour to digest a pre-run fuel source, the marathon runner will be better served to focus on simple carbs like a banana or sports drinks.
In both cases, again, it’s a good idea to avoid high-fiber foods and high-fat foods because they slow digestion and can cause cramping and digestive distress while running.
What Are the Best Foods to Eat Before a Long Run for Marathon Training?
Now that we’ve covered some of the basics about the importance of carb loading for marathon running and longer workouts, here are some ideas of the best high-carb foods to eat before a long run during marathon training or other long-distance workouts.
What To Eat Before A Long Run
- Oatmeal or porridge
- Cream of wheat hot cereal
- Low-sugar whole-grain cereals that don’t have much fiber. If you only have 30-60 minutes before your race, dry, plain cereal like Cheerios, Chex, or Kix can be good.
- Bananas
- Low-fat muffin and a hard-boiled egg
- Pretzels with peanut butter
- Applesauce
- Plain croissant with low-fat cheese
- Rice cakes
- Whole-grain waffles or pancakes can also provide the energy-sustaining carbohydrates you need without tons of fiber, fat, or protein. You can top them with applesauce, peanut butter, jam, fresh fruit, maple syrup, or butter.
- Fig Newtons or other whole wheat fruit cookies
- Fruit cereal bars like Nutrigrain bars
- Toast, bagel, or English muffin with jam, butter, or nut butter. Since nut butter contains fat, ensure you have at least 90 minutes to 2 hours before your race to digest this type of pre-race or pre-long run meal.
- Whole-grain crackers with jelly and peanut butter, or an English muffin with butter and jam.
- An energy bar like Bobo’s Oat Bars or Bob’s Red Mill Oat Bars
- Dried fruit such as raisins, craisins, yogurt-covered raisins, dried apples, dried pineapple, dates, dried apricots, and figs all work well for many runners.
- Fruit smoothies with bananas, almond milk or coconut water, berries, and Greek yogurt (as long as you aren’t sensitive to dairy) or protein powder.
- Sweet potatoes
- Whole wheat bread with healthy fats like peanut butter or almond butter
- Mashed potatoes
- White rice
- Quinoa
- Whole wheat pasta or couscous
- Pastina
What Should I Eat During a Long Run?
According to the American College of Sports Medicine (ACSM), endurance athletes should ingest 30–60 grams of carbohydrates per hour during workouts lasting 1-3 hours or more.7American College of Sports Medicine. (2009). Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 41(3), 709–731. https://doi.org/10.1249/mss.0b013e31890eb86
However, more isn’t necessarily better.
Evidence suggests that the maximum rate of carbohydrate absorption during exercise is 60 grams per hour. Therefore, sticking to the 30-60 grams of carbohydrates per hour recommendation for a long morning run or on race day is a good idea.8Jeukendrup, A. (2013). Carbohydrate Supplementation During Exercise: Does It Help? How Much is Too Much? Gatorade Sports Science Institute. https://www.gssiweb.org/sports-science-exchange/article/sse-106-carbohydrate-supplementation-during-exercise-does-it-help-how-much-is-too-much-
Keep in mind that because there are 4 calories per gram of carbohydrates, 30-60 grams works out to 120-240 calories of carbohydrates per hour.
Some of the best foods for distance runners during half marathon or full marathon training sessions that exceed 90 minutes include sports supplements like energy gels or chews, or whole foods such as dried fruit, pretzels, or bananas.
Sports beverages that have glucose and electrolytes serve double duty because they also aid hydration, but most sports drinks do not have a sufficient number of grams of carbohydrates for fueling during a marathon long run.
Consider working with a nutritionist or registered dietitian to find what to eat the night before a long run and before a morning run based on your individual needs.
Overall, you’ll want to experiment with what foods work well for you and the optimal timing of when to have your breakfast before a morning run or when to have a pre-run meal before a long training run that you do in the afternoon or evening.
For more information on carb loading, check out this next guide:
Hi, great article.
I recently ran a marathon (5th of the year) and for the first time ever I had really bad leg cramps (calves, inner and outer thighs, shins and even my little toe). I’m looking for sensible reasons why it was the first time this had ever happened to me?
It was a challenging day for charity that finished with a marathon after a 28mile bike ride and a skydive. I’m figuring I didn’t eat enough, fair?
Nick,
Leg cramps could be a symptom of any of the following (or a combination):
– going out too fast
– not training or tapering sufficiently
– poor nutrition
– running on tired legs (i.e. your bike ride).
Do these ring a bell?