October is marathon season. Chicago, London, Amsterdam, Toronto. Hundreds of thousands of runners are toeing start lines this month, and a huge portion of them will slow dramatically in the final miles. Not because they didn't train hard enough. Because they didn't eat right.
Fueling a marathon is a skill. It requires planning, practice, and a willingness to eat on the move when your body isn't sending hunger signals. Get it right, and you run your race. Get it wrong, and the wall finds you somewhere around mile 18.
Here's exactly what to eat and drink before, during, and after 26.2 miles.
The 48 Hours Before the Race: Carbohydrate Loading Done Right
Carbohydrate loading isn't an excuse to eat pasta until you can't move. It's a targeted strategy to top up your glycogen stores. Your muscles store glycogen as their primary fuel source during sustained effort. A marathon depletes those stores almost entirely. Starting the race with full tanks pushes back the point at which you run out.
Research consistently shows that increasing carbohydrate intake to roughly 8-12 grams per kilogram of body weight per day in the 48 hours before a race significantly raises muscle glycogen concentration. For a 150-pound (68kg) runner, that's somewhere between 545g and 815g of carbohydrates per day. That's more than most people eat in three days of normal eating.
What this looks like in practice:
- White rice, pasta, and bread over whole grain options (easier to digest, lower fiber)
- Bananas, white potatoes, and low-fiber fruits
- Sports drinks to add carbohydrates without bulk
- Reducing fat, fiber, and protein slightly to make room for carbohydrates without overeating total calories
Don't try new foods. Don't eat at a restaurant you've never visited. The carb load window is not the time to experiment with your gut. Stick to foods you know your body handles well.
Race morning, eat your usual pre-run meal two to three hours before the start. Aim for 1-4g of carbohydrates per kilogram of body weight. Keep it low in fat and fiber. A bagel with peanut butter and a banana is a genuinely solid option. So is white toast with honey and a sports drink.
During the Race: The Numbers Most Runners Get Wrong
Here's where most recreational runners leave time on the table. The research is clear: endurance performance at marathon pace requires 60-90 grams of carbohydrates per hour. Some trained athletes using multiple transportable carbohydrates (glucose plus fructose combinations) can effectively use up to 120g per hour. Yet studies show the average recreational runner takes in far less than 60g per hour during a race. Many take in virtually nothing for the first hour.
That's a fueling deficit that compounds over time. Every kilometer you run under-fueled is a kilometer drawing down glycogen without replacing it. By the time you feel the effects, you're already behind.
A single standard gel contains approximately 20-25g of carbohydrates. To hit the 60g minimum, you need roughly one gel every 20-25 minutes after your first one. Most runners take one gel every 45 minutes or only at water stations. The math doesn't work.
Your fueling plan should look something like this:
- Miles 1-6: Start your first gel at 30-45 minutes, not when you feel tired
- Miles 7-18: One gel or equivalent every 20-30 minutes
- Miles 19-26: Maintain intake even as appetite drops. This is when most runners stop fueling entirely.
- Water at every station to aid absorption
The type of fuel matters too. Products combining glucose and fructose use different intestinal transporters, meaning your gut can absorb more total carbohydrate per hour without GI distress. Look for gels, chews, or drinks that list both. This is the same science that elite runners like Clayton Young, who is still chasing the American marathon record, have built their race-day protocols around.
Don't Wait Until You're Hungry: The Biggest Fueling Mistake
Hunger is a lagging indicator. By the time you feel it during a marathon, your blood glucose is already dropping and your performance is already suffering. Waiting to feel hungry before you fuel is one of the most common and most costly mistakes recreational runners make.
At marathon pace, you're burning roughly 100 calories per mile. Your body can store approximately 1,800-2,000 calories of glycogen. Even with full stores at the start, you're doing the math correctly when you realize you'll run through them completely before the finish line without supplementation.
Train your fueling strategy in long runs. Practice taking gels at 30 minutes regardless of how you feel. Practice drinking while running rather than walking through water stations. Practice the specific products you'll use on race day. GI distress during a marathon is extremely common, and it's almost always preventable through training and testing your fuel choices in advance.
If you're running your first marathon or have struggled with fueling in the past, a simple approach: set a timer on your watch for every 25 minutes. When it goes off, take in fuel. Remove the decision-making entirely.
Hydration: The Variable That Changes Everything
Carbohydrates get most of the attention, but hydration directly affects how well your body can use the fuel you're taking in. Even a 2% loss in body weight through sweat has been shown to impair performance meaningfully.
The current guidance from sports science organizations is not to drink to a fixed schedule but to drink to thirst during the race while making sure you never fall significantly behind. Overdrinking is a real risk too. Hyponatremia (low blood sodium from excess water intake) has caused serious problems in marathon finishers, typically in slower runners who drink too much plain water.
A practical strategy:
- Drink to thirst, not on a rigid schedule
- Take electrolytes from sports drinks or salt tabs every 60-90 minutes in warm conditions
- Don't force fluids if you don't feel thirsty early in the race
- In hot or humid races, adjust upward and consider sodium supplementation
Pre-hydrating matters too. Drink about 500ml of water or a sports drink 2-3 hours before the start. Urine should be pale yellow, not clear and not dark, before you line up.
After the Finish: The 30-Minute Window You're Probably Ignoring
You've crossed the finish line. Your legs feel like concrete. Eating is the last thing on your mind. This is exactly when nutrition matters most for your recovery.
The 30-minute window immediately after finishing a marathon is when your muscles are most receptive to glycogen replenishment. Muscle glycogen synthase activity is highest in this post-exercise period, meaning the carbohydrates you consume are shuttled into muscle storage far more efficiently than they would be even 60 minutes later. Miss this window, and your recovery takes significantly longer.
Target 1-1.2g of carbohydrates per kilogram of body weight in that first 30 minutes. Pair it with 20-40g of protein to trigger muscle protein synthesis and begin repairing the micro-damage accumulated over 26.2 miles.
Practical post-race options that are easy to eat when appetite is suppressed:
- Chocolate milk (a genuinely well-researched recovery drink with a favorable carbohydrate-to-protein ratio)
- A recovery shake with whey protein and a banana
- Greek yogurt with fruit and honey
- A sports drink plus protein bar if solid food feels impossible
Continue eating carbohydrate-rich meals every 2 hours for the rest of the day. Full glycogen restoration after a marathon takes 24-48 hours of sustained intake. Your body will be in a depleted state far longer than most runners realize.
Sleep and rest accelerate the process. So does keeping up with your general micronutrient intake in the days that follow. If you've been inconsistent with your nutrition in the lead-up to race season, now is the time to address the basics before your next event.
Build Your Race-Day Fuel Plan Now
Nutrition doesn't begin at the start line. It's been building for weeks. The runners who execute their fueling well on race day are the ones who've rehearsed it on long runs, tested their products, and committed to a plan before the gun goes off.
If you're heading into marathon season and still figuring out what running and racing look like for you, it's worth exploring the full picture of where the sport is going. Trail running is the fastest-growing outdoor sport right now, and the community around all forms of distance running is expanding rapidly. Whether you're on roads or trails, the fueling principles carry over.
The wall isn't inevitable. It's a fueling problem. And fueling problems have solutions.