Fueling for race day

While eating a quick snack can provide enough fuel for a short run or quick gym session, you’ll need to rewind a little bit to make the most of your pre-race nutrition and hydration. You could carb load for three days in the week leading up to the event, but if you’re new to it, the day before is a good place to start. Make sure you’re drinking plenty of water and slowly increase the amount of carbs you eat in each meal (look out for a future post on carb loading). Avoid any foods that cause you GI distress because as tasty as that curry might be at the time, it could come back to haunt you tomorrow! For help with carb loading, take a look at our carb load page and free carb load guide.

On race day itself, fueling should be easy, supportive, and simple, not a distraction or source of stress. Eating enough will ensure that you have sufficient energy at the start of the race, and as you won’t be in a calorie or carb hole, will make it easier to refuel during it. Though it’s individualized, a good rule of thumb is to consume around 75 grams of simple carbs 2-3 hours before your race. Finishing a bagel and a small banana or 6 graham crackers two hours before the event takes care of that. 

If your race has a later start – such as the Boston Marathon – try eating a meal that contains 0.5-1 gram of carbs per pound of bodyweight with a bit of fat and/or protein 4 hours beforehand (like a bagel with peanut butter and a banana), then a high-carb snack 90 to 120 minutes before the start (such as six graham crackers). Or if you want to keep it even simpler, aim for 75g carb each at those times.

On the hydration side, plan to drink 8 – 16 ounces of water or sports drink , stopping 1 hour before race time, and then sip to thirst after that. If the weather changes and it’s going to be hotter and more humid, you might need a little more fluid and electrolytes. Whereas if the forecast calls for cooler temperatures, you may need a bit less if you’d planned for heat. Only make minor changes and try not to shake up your plan when you’re within 48 hours of the race itself.

So how can you know if your race day fueling strategy is or isn’t working? While helping my clients prepare for race day, some of the common red flags for underfueling seen during training include hitting the wall, struggling to obtain or maintain race pace, and the dreaded DNF (did not finish). Then there are digestive troubles, like nausea, inability to take gels later in the run or other GI distress. Underfueling problems on race day may include only taking one or two gels during a marathon and not drinking any fluids (yes, really). 

These are all indications that you need to do something different. In contrast, if you’re getting things right on race day, you should be fueling early and often, feeling supported by your nutrition and hydration the whole way, able to hold your race paces until the end, and finishing with a smile on your face. Remember that there’s always room for improvement. Someone told me he’d broken three hours for the marathon with no gels. My thought? “Imagine how much faster you’d go if you were fueling!”

One of the most common reasons for a race day fueling strategy falling flat is that the athlete is trying it out for the very first time. This is why I always remind clients to “practice, practice, practice.” You put so many hours into the physical elements of your training, so why would you leave your nutrition and hydration to chance? 

Finding the right fuel is much easier when you can test options during training. Sports gels are usually the best choice for most people. Try out different kinds until you decide which one works for you. Real food gels made from maple, rice, and other whole foods can work for some, but they’re more slowly absorbed so take that into account when selecting the best sports fuel for you. 

Practicing race day strategy in training also gives you the chance to figure out how you’re going to carry your fuel and fluid. A sports bra with a big pocket on the back has plenty of space if I don’t bring my phone. Another option is tucking a Koala Clip inside the back of their bra, wearing shorts with pockets up top so they’re not annoyed by gels bumping into their legs, or using an adjustable belt that you can fill with fuel. Some hold water bottles too, but if that’s too clunky, you’d be better off with a handheld bottle or hydration vest.  Find what works for you and practice!

When you’re still in the trial-and-error phase, it’s best to try out your fueling plan on longer, low-to mid-intensity runs. Eventually, you’ll want to practice with race-pace sessions, but as these higher-intensity runs are so physically demanding, you should build up to that. It’s going to be difficult to focus on split times if you’re experimenting with a new gel or tinkering with the timing of refueling. You’ve also got to get your body used to accepting and utilizing more fuel than you’re probably used to, which won’t happen immediately. Start by taking half a gel or portion of chews every time you refuel. It can take time to “train” your fluid intake too, so try slowly increasing this on each trial run.

Once you’ve finished experimenting with fuel choice, carbs-per-hour and fluid-per-hour amounts, and nutrient scheduling (keep reading for tips on all this), then it’s time to take things up a notch and put your refueling plan into action with a marathon-paced effort. This way, you’ll know if your strategy will stand up to race day demands. A study published in Sports Medicine asserted that you need to condition your gut to function in realistic, race-like conditions. “‘Nutritional training’ can improve gastric emptying and absorption and likely reduce the chances and/or severity of GI problems, thereby improving endurance performance as well as providing a better experience for the athlete,” the author wrote.

As the physiological load will be higher than during your earlier, slower efforts, you might find that things don’t go perfectly. That’s OK! Just make mental notes of what succeeded and didn’t, and then make small adjustments on your next practice run. Once you’ve repeated this experiment a few times, you should have ironed out the kinks. Then you’ll have confidence knowing that you’re going to show up on race day with a tried-and-true approach that will get you through the course. Now you just need to show up and put your fueling plan into action. 

Carbs are going to keep you going faster for longer on race day. A research duo from Maastricht University Medical Center in Holland stated that “carbohydrate ingestion during prolonged (>2 h) moderate-to-high intensity exercise can significantly improve endurance performance.” The authors went on to say that while older studies suggested 60 grams per hour was the limit for usable carb consumption, “well-trained endurance athletes competing longer than 2.5 h can metabolize carbohydrate up to 90 g/h.” Most people are usually in the 30-to-60 gram range, though if I’m working with an elite athlete, they might need to go beyond that. To figure out your personal race fueling needs, use my free calculator. 

Just like on any long run, it’s essential to fuel early and often in a race. When combined with proper pre-race nutrition, nailing your carb intake in the first half will set you up to finish strong and means that if you miss a gel later, it’s less of an issue (same goes for fluid). One of the major mistakes I see is delaying the first fuel-up. If you wait to take a gel until you feel you need it, you’re actually way past the point that your body requires that energy. Then it will take at least 15 minutes more for the gel to be absorbed, by which point you might be running on fumes. So, make sure you take your first gel in the first 30 minutes of the race and then roughly every 30 minutes for the rest of the race.

If you happen to miss a gel, you might be tempted to take two at the next half-hour interval. I’d advise against that because it might be too much for your stomach to handle. Maybe you take the next gel less than 30 minutes out and adjust the rest of your fueling schedule from there, but don’t try to cram too much in to catch up or it could backfire. 

To stay hydrated and help your body absorb mid-race carbs, aim for at least five to 10 ounces of fluid per hour. If you are a heavy sweater, or it’s hot or humid, you may need more (take a look at our hydration page for more detail). You can achieve this by sipping water or a sports drink (yes, you can mix this with gels) or by drinking one to two aid station cups per hour. To make this easier, get your gel down before you reach the station so you’re not fumbling with both. Don’t wait till you get to race day to figure this out – plan ahead to know where water and aid stations will be and what they’ll offer. Then combine that on-course fluid with whatever you’re going to bring along. Remember that drinking to thirst isn’t going to work while racing – you need to stick to your hydration and fueling plan. 

As you’ll be losing sodium, you will need to replenish this through a combination of your fuel and fluids. Some gels – like Maurten  – might not contain enough by themselves, so you can use a sports drink like Skratch Sports Hydration. Again, play with this combo during training runs so you’ve nailed it well before race day. Important note: Hydration needs are highly individualized – if you need help with your race day hydration, take a look at our Customized Race Fuel & Hydration Plan.

Caffeine can be a touchy subject for many racers. If you drink it every morning, then feel free to on race day. If you don’t normally drink caffeine, it may not be the best choice for you. During the race, a line of best fit is to alternate caffeinated and non-caffeinated gels. This might be too much for you if you’re sensitive to caffeine or metabolize it quickly – again, this is where practice runs come in. We’ll do a separate post on caffeine soon, but in the meantime, you can read more here, and remember that it takes 60-90 minutes for it to peak in your system so consider your timing carefully.