The Runner’s Guide to Race-Day Fueling

Jason Fitzgerald
by Jason Fitzgerald
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The Runner’s Guide to Race-Day Fueling

Most runners have heard this advice before:

1. “Don’t do anything new on race day.”
2. “Practice your race-day nutrition and hydration during training.”

But if you’re a new runner and/or have just started racing, you may have no idea how to apply this advice to meet your specific training and race-day needs. Strategies for fueling vary significantly based on the distance you’re running, so it’s essential to learn how to fuel your body for different types of races.

Nutrition is a critical component of your running success. Adequate fueling will help you tackle longer races successfully and also improve your speed over all distances. But you need to dial in what works well for you long before you get to the starting line.



For simplicity, the fueling plans in the following sections refer primarily to energy gels as a carbohydrate source. Because there are so many brands and flavors, most people can find one that works for them. Most gels have a mix of glucose and fructose that can provide optimal fueling, but they are certainly not the only option. Energy chews and “beans” are also available, and some runners prefer more natural, whole-food sources like dates or dried fruits. As race intensity (how hard you run) increases, your stomach may be less tolerant of foods with fiber, fat or complex carbohydrates.

If you choose to use gels, it’s essential to take them with a few ounces of water to facilitate digestion. Because they’re a concentrated source of carbohydrates, eating gels without water or in combination with a carb-rich sports drink can make them challenging to digest.


When it comes to hydration, there’s a lot of conflicting advice. Individual needs can vary dramatically and are affected by conditions such as air temperature, altitude and humidity. Keep in mind just two simple things when it comes to hydration:

1. Start your race well hydrated—you’re good if your urine is a pale yellow color. Once you’re hydrated, stop drinking at least 30 minutes prior to race start to avoid unnecessary bathroom stops (unless it’s a superhot or humid day—in this case, it’s best to drink enough to be well hydrated, no matter how close it is to the race start).

2. Drink to quench thirst during the race itself. Most runners need approximately 8–16 ounces of fluid per hour, but if you feel overly thirsty during a race, then you’re not drinking enough. Don’t overcomplicate it!

Of course, no discussion of race fueling is complete without talking about caffeine, many runners’ legal drug of choice—and with good reason. Caffeine can improve race-day performance; it can increase alertness, delay fatigue, improve your fat-burning ability and decrease your perception of pain. Most runners can experience these benefits with just 100–200 milligrams of caffeine taken 60–90 minutes prerace. Taking caffeine is a personal choice and, like everything else, you should test its impact on you well ahead of race day.


For most runners, a normal diet will be adequate to fuel 5K and 10K races—no gels, beans or chews necessary. Half marathons represent a significant jump in mileage, and marathon and ultrarunners have serious fueling requirements that need more forethought and preparation than shorter events. Let’s look at some of the specifics.

Fueling for 5K and 10K races

While you can probably get away without a prerace meal at these distances, it’s ideal to have a runner-friendly breakfast that’s high in carbohydrates but low in fat to optimize your performance. If you’ll be eating two hours or less prior to the start of the race, stick to a small meal of approximately 200–300 calories. Some options include oatmeal with fruit or toast with a small amount of nut butter. If you are running a race later in the day or have more than two hours prior to the start, you can have a slightly larger meal so you don’t start the race hungry.

Since 5K races are short, you don’t need any additional fuel during the race itself. The same is typically true for 10Ks, though if you’ll be out on the course for over an hour, you may want to take a gel midrace to help you finish strong. Follow the hydration advice above to run your best on race day.


For half marathons, successful fueling begins the day prior to the race. While you don’t necessarily need to “carbo-load” the way you would for a marathon or ultra, it’s still essential to top off your glycogen stores (sugar/carbs stored in your muscles and liver) adequately prerace. The night before your race, your dinner should include two sources of complex carbohydrates, such as rice, pasta, quinoa and sweet potatoes.

Race-day fueling

Breakfast on race morning should also be larger than what you would consume before a 5K or 10K, though you still want to stick with high-carb, low-fat, easily digestible foods. Try to eat your meal at least three hours prior to the start of the race to allow adequate time to digest. Stick with foods you eat regularly that you know won’t cause any digestive upset. If you’re traveling to a race, check out your breakfast options ahead of time or bring your own food from home, especially if you have a sensitive stomach.

Race fueling for a half marathon depends on your predicted finish time. If you anticipate being out on the course for two hours or more, you’ll need to take in more calories than a runner expecting to finish in 90 minutes or less. Most runners should try to consume approximately 2–3 gels, evenly spaced throughout the race. For a two-hour half marathoner, this means taking a gel at 30, 60 and 90 minutes. Two gels will probably be sufficient for a runner finishing under 1:45, though this will vary depending on each runner’s unique requirements. Follow the hydration advice above to run your best on race day.


A 2009 study of midpack runners at the London Marathon showed that the vast majority of individuals underfueled the day before the race. In contrast, those who fueled sufficiently averaged approximately 13% faster finish times!
So how many carbohydrates should a long-distance runner plan to ingest? Researchers advocate 7–10 grams per kilogram of body weight. For a 150-pound runner, this translates to about 470–680 grams of carbohydrates before the race start.

If you try to consume all these carbs in the form of pasta, you’ll likely find yourself completely overstuffed. This is where sports drinks come in handy: They can provide about 60 grams of carbs per liter and are especially useful for prerace carbo-loading.

Although many associate pre-marathon dinners with an all-you-can-eat pasta buffet, it’s best not to overdo it the night before the race. Stuffing yourself with carbs can leave you feeling sluggish instead of energized. Start your carbo-loading two nights before your race, and try to space your meals evenly throughout the day so your digestive system isn’t overwhelmed the night before.

Race-day fueling

It’s ideal to consume approximately 45–60 grams of carbohydrates per hour during a marathon. It’s easier to digest carbs in smaller quantities, so eating one gel every 30 minutes is a good strategy. As with the half marathon, your total requirement for carbohydrates will vary depending on your predicted finish time. The longer you’re out there, the more fuel you’ll need. Make sure you start fueling early, and stick to your plan! Follow the hydration advice above to run your best on race day.


After you cross the finish line of any race, try to take in about 100–300 calories to help expedite the recovery process. Carbohydrates are ideal along with a small amount of protein. Energy bars, sports drinks or chocolate milk are all good options. If your stomach is queasy from your effort, liquids may be easier to ingest than solid food.

Once you’re home, a full meal that includes complex carbohydrates, protein and healthy fats will help you recover from your effort. Your postrace meal becomes even more important after running 26.2 miles—make sure you refuel adequately to help your body begin the recovery and repair process.


Now that we’ve discussed the essentials of race nutrition, the next step is to address your fueling strategy prior to the big day. If you plan to use energy gels, try a variety of brands and flavors (caffeinated and uncaffeinated) to see what suits you best.

You should also research what fuel and hydration options will be offered at the aid stations during your race and decide if you want to carry your own fluids or rely on what the race supplies.

While your daily training runs will provide ample opportunity to figure out what foods you can easily digest, long runs are ideal to practice race-day fueling. Test out your preferred carbohydrate source on several longer runs. At least one long run should serve as a race-day dress rehearsal, where you practice your prerace meal, run at the same time of day as your race, take your gels (with water) at regular intervals and drink according to thirst.

If you’re new to longer races, give yourself adequate opportunity to fine-tune your nutrition strategy. Take notes so you can keep track of what works best.

Race fueling requires some forethought and practice, and you’ll continue to fine-tune your strategy over months or even years of racing. The benefits are well worth the effort, so stick with it and learn what helps you race your best.

About the Author

Jason Fitzgerald
Jason Fitzgerald

Jason is the founder of Strength Running, a USA Track & Field certified running coach and 2017’s Men’s Running’s Influencer of the Year. Learn more about how he can help you run faster.


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