Marathon Nutrition Plan: What to Eat Before, During, and After
2026-06-14 · 5 min read
Rapid answer
Load 10 to 12 g of carbs per kg bodyweight in the 36 to 48 hours before the race. Eat 1 to 4 g/kg race morning 2 to 3 hours before start. Take 60 to 90 g of carbs per hour on course starting at mile 4. Replace 500 to 1,000 mg of sodium per hour in heat.
A marathon depletes muscle glycogen stores completely in most runners by mile 20 to 22. Nutrition does not prevent that wall entirely, but the difference between a well-fueled runner and a poorly fueled one at mile 22 is the difference between a negative split and a death march. Here is the full plan.
The week before: carb loading
In the final 36 to 48 hours before race day, eat 10 to 12 grams of carbohydrate per kilogram of bodyweight per day. This is substantially more than your normal intake and is designed to supersaturate muscle glycogen stores.
Use the carb loading calculator to get your exact target in grams based on your bodyweight and event type. For a 70 kg runner, that is 700 to 840 g of carbs per day for two days. That requires focusing almost entirely on carbohydrates and dramatically reducing fat and fiber.
Best carb loading foods: white rice, white pasta, plain bagels, bananas, honey, white bread, rice cakes. See 36-hour carb loading food list for a full breakdown by meal.
What to avoid: vegetables, whole grains, beans, legumes, high-fat foods, alcohol.
Race morning: topping off glycogen
Eat 1 to 4 grams of carbohydrate per kilogram bodyweight 2 to 3 hours before the start. This replenishes liver glycogen depleted overnight without adding food that will still be in your stomach at the gun.
For a 70 kg runner at 2 g/kg, that is 140 g of carbohydrates (roughly 2 cups of cooked white rice or 2 large bananas and a bagel). See what to eat race morning for timing and food options.
Drink 5 to 7 mL of fluid per kilogram in the 2 to 4 hours before start. A 70 kg runner needs 350 to 490 mL (roughly 12 to 16 oz). Have an additional 150 to 350 mL 15 minutes before the gun.
On-course fueling: carbohydrates
Start fueling at mile 4 to 5 (not when you feel tired). Aim for 60 g of carbohydrates per hour using a dual-transport gel (glucose plus fructose), or up to 90 g per hour if your gut is trained for it.
Use the carb calculator for your exact hourly target based on event duration. For a 4-hour marathon:
| Time | Action |
|---|---|
| Mile 4 to 5 (30 to 40 min) | First gel (25 to 40 g carbs) |
| Mile 9 (60 to 70 min) | Second gel |
| Mile 13 (90 to 100 min) | Third gel or race-course gel |
| Mile 17 to 18 (120 min) | Fourth gel |
| Mile 21 to 22 (150 min) | Fifth gel (consider caffeine gel here) |
For gel recommendations see best marathon gels.
On-course fueling: sodium and electrolytes
Replace 500 to 1,000 mg of sodium per hour in warm conditions. At water stations, drink electrolyte sports drink rather than water alone. In heat above 75 degrees Fahrenheit (24 degrees Celsius), supplement with an electrolyte tab at every other aid station.
Use the sodium calculator to personalize your target. Heavy sweaters in heat may need 1,000 to 1,500 mg per hour. Light sweaters in cool conditions may need less than 500 mg. See best electrolyte tablets for runners for product options.
Caffeine: when and how much
Caffeine at 3 to 6 mg per kilogram improves late-race performance and reduces perceived effort. For a 70 kg runner, that is 210 to 420 mg. Time your primary dose 45 to 60 minutes before the start. Consider a secondary dose (75 to 100 mg) at mile 18 to 20 for the final push.
Use the caffeine calculator for your exact dose. See caffeine timing for endurance athletes for the full protocol. For caffeinated gel options, see best caffeine gels for racing.
After the race: recovery nutrition
Within 30 to 45 minutes of finishing, eat or drink 1 to 1.2 g of carbohydrate per kilogram of bodyweight alongside 20 to 25 g of protein. The protein-carbohydrate combination accelerates glycogen resynthesis and starts muscle repair. Chocolate milk (roughly 30 g carbs and 8 g protein per 8 oz) is a practical option.
Continue eating high-carbohydrate meals for 24 to 48 hours post-race. Expect appetite to be suppressed for several hours; liquid nutrition (smoothies, sports drinks) is easier than solid food in the first couple of hours.
For longer events, the fueling demands scale significantly. See the Ironman nutrition plan for 140.6 and 70.3 carb and sodium targets by hour.
Common marathon nutrition mistakes
- Starting gels too late: Waiting until mile 10 to start fueling puts you behind. Gut absorption takes 20 to 30 minutes; starting early keeps blood glucose stable.
- Skipping electrolytes in heat: Water alone at aid stations dilutes blood sodium and accelerates hyponatremia risk in hot races. Take the sports drink.
- Using new products on race day: Never introduce a new gel brand or flavor in a race. Test everything in training.
- Carb loading with high-fiber foods: Vegetables and whole grains are healthy normally but cause GI distress during carb loading. Stick to low-fiber options.
Frequently asked questions
What should I eat the week before a marathon?
In the final 3 to 4 days before a marathon, progressively increase carbohydrate intake and reduce training volume. In the final 36 to 48 hours, follow a structured carb loading protocol: 10 to 12 g of carbohydrate per kilogram of bodyweight per day from white rice, pasta, bread, and bananas. Cut fiber, fat, and alcohol. The goal is to arrive at the start line with fully saturated glycogen stores, not just a large meal the night before.
How many gels should I carry in a marathon?
For a 3 to 4 hour marathon targeting 60 g of carbs per hour, you need 7 to 10 gels (at 22 to 25 g each). If you are using higher-density gels like SiS Beta Fuel (40 g per sachet), you need 6 to 7. Most races provide gels at mile 13 and mile 20, so you may only need to carry 3 to 4 of your own if you know the course gel is one you train with.
Should I drink Gatorade or water at marathon aid stations?
Take the sports drink at most stations, particularly in warm conditions. Sports drinks provide both carbohydrates and sodium, addressing two nutritional needs simultaneously. The exception is if you are already consuming high-carb gels on a strict schedule and are worried about GI overload. In that case, alternate between sports drink and water at aid stations to manage total carb intake while still getting electrolytes.