Knowing how much to eat and drink during your race can be a tricky task: consume too much and you run the risk of gastrointestinal (GI) distress; consume too little and you could bonk or get dehydrated. Of course, your calorie and fluid needs vary significantly depending on the race duration, so we’ve created this guide to race fueling by distance—from sprint all the way through to long course. We’ve also added suggestions for pre-race nutrition options. Remember (as is the case with most things): Don’t try anything new on race day! Make sure to test everything in training so there are no surprises when the gun goes off.
Sprint Distance (up to 90 minutes)
Fueling for sprint racing is more about what you consume pre-race than what you consume in the race itself.
One to three hours pre-race: The goal is to top up glycogen stores and prevent hunger. Be wary of too much fat and fiber. Good options include: low-fiber toast with nut butter and jam or avocado; cereal with milk/milk alternative; oatmeal with berries.
30 minutes before: Sip on your preferred hydration drink (ideally a lower-carbohydrate, higher-electrolyte option).
During the race: For the shorter distances (up to an hour), your job is to focus on hydration, taking small sips throughout the race. If you are lagging on the run, you can use a few glucose tablets or energy chews to boost your blood sugar. If racing for closer to 90 minutes, hydration is still a focus (aim for 0.1 to 0.15 fluid ounces per pound of body weight), but look to top up with carbohydrate for the last half of the race. It’s not about how many calories or grams of carbohydrate per hour, but rather about boosting blood glucose. Aim for one to two energy chews every 15 minutes.
Olympic Distance (2.5 to 4 hours)
An Olympic-distance race is interesting from a nutrition perspective as it stretches the fueling limits to the point where you do need to pay attention, plan, and have it dialed in. For some, this distance is about hard sub-threshold racing, while for others it might be slightly less intense with the goal of finishing well. This can obviously change fueling options, so if you’re planning to race at high-intensity, make sure you practice what works for you when your body is under duress.
One to three hours pre-race: Eating before the race is critical to top up glycogen, prevent hunger, and boost blood sugar for the swim. Similar to sprint racing, you want to be wary of too much fat and fiber content, but still have a good hit of nutrition density. Aim for 300-400 calories in your pre-race meal. Good options: low-fiber toast or bagel with jam, a serving of instant oatmeal with protein powder, a banana with nut butter, or a banana smoothie (frozen banana, a packet of instant oatmeal, one scoop of protein powder, milk/milk alternative/water).
30 minutes before: Sip on a hydration drink (lower carbohydrate, higher electrolyte). If it’s been three hours or more since you last ate, aim to eat half of an energy bar or half of a bagel with jam to top off glycogen stores. However, if you are nauseous/nervous, it may pay to have a few chews instead, as they are easier to digest.
During the race: Once out of the swim, focus on hydration with small sips of drink, and then aim to eat 200-300 calories of food per hour. Good options include: energy chews, stroopwafels, or small bites of energy bars. Stay focused on hydration, aiming for 0.1 to 0.15 fluid ounces per pound of body weight. Whatever you opt for, make sure it’s easy to digest and won’t lead to blood sugar swings. On the run, it’s about keeping blood sugar up to maintain pace and prevent dips in energy. Energy chews, soft candies, Coke, and glucose tablets are all good options here.
TIP: Aim to top off glycogen stores 30 minutes pre-race with half an energy bar or a few energy chews
70.3 Distance (4 to 7 hours)
Many 70.3 races start early, which—if you live by the “eat breakfast three hours pre-race” rule—can mean setting your alarm very early! While some athletes will always want to do this, it’s not essential. Regardless of when you eat, the focus for your race-morning breakfast should be on topping up the glycogen that was used during sleep.
One to three hours pre-race: Consume an easy-to-digest, low-fiber, higher-complex carbohydrate breakfast. Go with what you know. This can be as simple as toast with nut butter and jam, or a smoothie for those who struggle with solids on race morning. Try instant oatmeal mixed with 6-10 ounces of milk/milk alternative. You can add in protein powder, but the sugar and sodium of the instant oatmeal are great for pre-race top ups.
30 minutes before: Sip on a hydration drink (lower carbohydrate, higher electrolyte). If it’s been three hours or more since you last ate, aim to eat half an energy bar or half a bagel with jam to top off glycogen stores. However, if you are nauseous/nervous, it may pay to have a few chews instead as they are easier to digest.
During the race: When it comes to fluid needs, follow the same guidelines as outlined for sprint and Olympic: 0.1 to 0.15 ounces per pound of body weight per hour of racing. Drink to thirst for the first two hours, and then set an alarm to remind yourself to stay on schedule with fluid intake. As you fatigue, it can become easy to lose track and/or lose focus.
On the bike, your calorie intake should be between 1.4 to 1.8 calories per pound of body weight per hour. If this seems like a lot, remember that you are “front-loading” calories to ensure you have reserves for the run too. As an example, a 130-pound athlete should be looking to consume ~180 to 230 calories per hour.
On the run, the goal calorie intake should be between 1 to 1.5 calories per pound of body weight per hour. The goal here is different than the bike—it’s simply to keep blood sugar up and minimize digestion issues, which is where energy chews, soft gummy candies, and jelly beans all come into play. Coke and glucose tablets can work well in the last 40 minutes.
Full Distance (8-17 hours)
As with 70.3 racing, Iron-distance events often start early, so the same rule applies here—no need to stress about eating three hours before (unless you want to!), but do make sure to top up glycogen with your usual pre-race breakfast options.
Pre-race: Sip on electrolyte drink up to swim start, top up on fuel with half an energy bar or half a bagel with jam 30-45 minutes pre-race. Energy chews are also a good option.
During the race: For the first half of the bike, take on 0.1 to 0.15 fluid ounces of electrolyte drink per pound of bodyweight per hour. For fuel, the goal is 1.5 to 2 calories per pound of bodyweight per hour, and it’s important to go for mixed macronutrients to keep energy levels even and allow less full glycogen depletion to occur. Remember that small bites of food frequently are better than huge calorie intakes all at once. Good examples include: small salted potatoes, white bread peanut butter and jelly sandwiches, and energy balls.
On the second half of the bike, aim to keep it similar if you can, but it’s not uncommon to feel like you can’t stomach solid foods. If this happens, stay focused on hydration, and move to energy chews or even candy, but try to avoid that until the last hour. Wait for your stomach to settle and resume food calories if/when you can.
On the first half of the Ironman run, aim for 1 to 1.5 calories per pound of bodyweight per hour—small bites of energy bars or salted sweet potato bites. Aid stations often offer pretzels or potato chips, as well as energy bars and chews, so small quantities of these are good if you can stomach them (only if you’ve practiced this in training). The goal, though, is to keep blood sugar up and minimize digestion issues. Keep consuming electrolyte drink—ideally from a bottle you carry with you from T2. Obviously this isn’t possible throughout the entire marathon, but you can adapt by using on-course electrolyte drink diluted with water.
As the race goes on, it’ll likely get harder and harder to keep eating and drinking. Move to energy chews or jelly beans for the last six to eight miles of the marathon (and Coke too) and also remember that glucose tablets are a great go-to—take them on every five to seven minutes.