The most important thing to eat before a marathon is carbohydrates, and lots of them. Your muscles store carbohydrates as glycogen, which is your primary fuel source during 26.2 miles of running. The days leading up to race day are about maximizing those glycogen stores, while race morning is about topping them off without upsetting your stomach.
Carb Loading: 2 Days Before the Race
Carb loading isn’t just eating a big pasta dinner the night before. It’s a deliberate strategy that starts 36 to 48 hours before the gun goes off. During this window, aim for 10 to 12 grams of carbohydrates per kilogram of body weight each day. For a 70-kilogram (154-pound) runner, that’s 700 to 840 grams of carbs per day, which is a significant amount of food.
To hit those numbers, carbohydrates need to be the center of every meal and snack. That means prioritizing carbs over fat and protein at each sitting. Think rice, bread, pasta, potatoes, bagels, pancakes, cereal, and fruit. You’re not eliminating protein and fat entirely, but they take a back seat. A plate that’s normally half vegetables and a quarter starch flips to mostly starch with smaller portions of everything else.
This is also not the time to cut calories. Even though your training volume drops during taper week, your body is still repairing accumulated muscle damage and fatigue from months of hard training. Restricting food intake forces your body to prioritize basic functions over recovery. Eat to fuel and repair, not to match your reduced mileage.
What To Eat the Night Before
Your final dinner before the marathon should be familiar, carb-heavy, and relatively plain. This is not the night to try a new restaurant or an adventurous cuisine. Stick with foods you’ve eaten before long training runs and know sit well in your stomach.
Good options include:
- Tomato pasta with a side of garlic bread
- Margherita pizza
- Gnocchi with tomato sauce
- Baked potatoes
- Fried rice with egg
- Chicken kebab with pitta and rice
- Noodle soup like pho or ramen
- Sushi or a poke bowl
- Sweet potato tacos or quesadillas
- Curry with rice and naan (mild, without legumes)
Adding lean protein is fine. A piece of chicken on your pasta or some tofu in a stir-fry rounds out the meal without weighing you down. Choose marinara sauce over creamy, cheesy options. Pick a baked potato over fries. Keep toppings simple. You can also have dessert: rice pudding, ice cream, or gelato all add easy carbohydrates without much fiber.
Foods To Avoid in the Final 48 Hours
Gastrointestinal distress is one of the most common reasons marathoners slow down or drop out, and what you eat in the two days before the race plays a direct role. High-fiber foods like broccoli, cauliflower, beans, and legumes are harder for your body to break down, and during a long run they’re more likely to sit and slosh in your stomach.
Steer clear of very spicy foods, rich or deep-fried meals, and anything you know triggers stomach issues for you personally. Many runners also avoid alcohol before a race, since it can impair sleep quality and contribute to dehydration. If onion, garlic, or certain raw vegetables tend to bother you, skip them too. The general rule: nothing new, nothing adventurous, nothing that makes your gut work harder than necessary.
Race Morning Breakfast
Your race morning meal tops off liver glycogen that depleted overnight. Aim for 1 to 4 grams of carbohydrates per kilogram of body weight, eaten 1 to 4 hours before the start. For most runners, that means eating about 3 hours before the gun, which often means a very early alarm.
A 70-kilogram runner eating 2 grams per kilogram needs about 140 grams of carbs. That could look like a large bagel with jam and a banana, or a bowl of oatmeal with honey and a sports drink. Keep fat and fiber low. White bread, white rice, bananas, and energy bars are better choices than whole-grain toast with peanut butter. Again, eat only what you’ve practiced during training. Race morning is not the time to experiment.
If you’re someone who struggles to eat early in the morning, start with a smaller amount and sip on a carbohydrate drink. Even a few hundred calories will help. Some runners eat a slightly larger meal 4 hours before, then have a small snack like a gel or half a banana closer to the start.
Hydration Before the Race
Aim to drink 16 to 24 ounces of water or a sports drink about two hours before the start. This gives your body time to absorb the fluid and lets you use the bathroom before lining up. Sipping a sports drink rather than plain water also adds a small amount of carbohydrate and sodium, which helps your body retain the fluid rather than sending it straight through.
In the days before the race, drink consistently but don’t force excessive amounts. Your urine should be pale yellow. If it’s clear, you may be overdoing it, which can dilute your sodium levels. If it’s dark, you need more fluids. Pair your carb loading with a sports drink or add a pinch of salt to meals to help your body hold onto the extra water it needs to store glycogen.
Beetroot Juice as a Pre-Race Boost
Beetroot juice is one of the few legal performance supplements with consistent evidence behind it. It works because it’s rich in nitrates, which your body converts into a compound that helps your muscles use oxygen more efficiently. The optimal dose is about 8 millimoles of nitrate, consumed 2 to 2.5 hours before exercise. At that dose, studies have shown improvements in time to exhaustion of 12 to 14 percent.
You can find concentrated beetroot juice shots in most health food stores, typically sold as 70-milliliter (about 2.3-ounce) bottles standardized to 8 millimoles of nitrate. Drinking one of these shots on race morning, roughly 2.5 hours before the start, is the simplest approach. Be aware that beetroot juice will turn your urine and possibly your stool a reddish color. This is harmless, but it can be alarming if you’re not expecting it. Practice with it during training before using it on race day.
Putting the Timeline Together
Two days before the race, shift your diet to 10 to 12 grams of carbs per kilogram of body weight daily. Keep fiber low, keep meals familiar, and don’t restrict calories even though you’re barely running. The night before, eat a carb-rich dinner you’ve had before, with a small amount of lean protein and minimal fat. Go to bed well-hydrated.
On race morning, eat 1 to 4 grams of carbs per kilogram about 3 hours before the start. Drink 16 to 24 ounces of fluid 2 hours out. If you’re using beetroot juice, take it 2.5 hours before. Then trust the preparation you’ve done over the previous 48 hours. Your glycogen stores are full, your gut is settled, and you’re ready to run.