Running a marathon demands a lot from the body. When it’s in peak marathon shape, the body possesses the strength and endurance needed to run for miles. The body also needs to be able to withstand all the calories and liquids runners ingest to fuel their many miles. This calls for a special diet, which covers everything from what runners eat to how often they eat. Ahead, find some great nutritional tips for marathon runners.

Don’t Forget to Hydrate

Every marathon runner knows the important of drinking water. Drinking adequate amounts of liquid is easier said than done, however, especially if you need to replenish your water stores as frequently as your average marathon runner. Water is necessary for healthy homeostasis in the body, the process responsible for getting rid of metabolic waste and sending nutrients to cells. If runners don’t get enough water, they are at greater risk for fatigue and heat illness.

While most people can follow the eight glasses of water per day rule, runners are different. They should rehydrate at regular intervals throughout each day—even if they’re not going for run. Before they exercise, they should drink at least one cup of water an hour prior to their workout and one cup of water during their workout. Afterwards, they should drink water to replenish the liquid they lost via perspiration. When they’re participating in a race, they need to increase their water allotment. In the hours before the race, they should guzzle down two or three glasses of water, giving their body ample time for excretion.

Finding the Right Mixture of Carbs and Protein

Many runners struggle with the number of calories they have to eat everyday to maintain their stamina. Even harder? Striking the perfect balance between carbohydrates and protein. Both food groups are essential for runners—carbohydrates provide energy, and protein helps with muscle recovery. As a general rule of thumb, runners should try to consume 6 grams of carbs for every 1.5 grams of protein. But what kind of carbs and proteins are best?

For many runners, the best options are a matter of tolerance. Given the number of calories necessary for runners, if their daily carb intake consisted entirely of fruit, for example, it could cause digestive problems. Runners should opt for carbs and proteins that they don’t have problems digesting. They may want to skip refined grains, which can cause constipation, as well as foods high in fat, which can be hard to digest. Instead, runners should opt for proteins and carbohydrates that will help to regulate the digestive system—like fiber-filled whole-wheat carbs.

Food Timing

If you’re not a professional marathon runner, you probably don’t need to time your meals down to the last second. Nonetheless, it’s always a good idea to be strategic about when you eat. You should never run on an empty stomach, for example—try to eat a light but nutrient-dense snack about an hour before you run. Make sure your snack has some carbohydrates, as they help to raise blood glucose to the appropriate levels. As marathons can go for hours, most runners need to refuel during the race. After the first hour of running, try to eat 30 to 60 grams of carbohydrates at regular intervals. Bananas and energy gels are great ways to sustain energy during marathons. Post-run, make sure to eat a meal loaded carbohydrates, protein, and hefty dose of salt. Salt helps the body retain water, and it also incites thirst, which will encourage you to drink the water you need after a run.

To keep energy levels high on ordinary days, try to eat small meals throughout the day, rather than the three big meals most people prefer. Space the meals out, eating one every three hours.

Work Around Your Schedule

If you lead a busy life, it can be hard to balance your dietary needs with your daily schedule. It’s easy to devise a solid nutrition plan, but it’s harder to stick to your dietary goals. Every day, good diets get derailed by office vending machines and after-work fast food runs. To maintain your diet when dealing with a busy or hectic schedule, meal and snack prep is essential. On Sunday, prepare enough Ziploc bags filled with your favorite healthy snacks to sustain you through the workweek. If you don’t mind leftovers, buy a slow cooker, which will enable you to make large batches of healthy foods that you can eat throughout the week. Make sure you always have healthy food on hand—whether you’re heading to work or the gym or to the mall—as it will prevent calorie-high, nutrient-low snacking.