Preparing for a run isn’t just about the training hours you put in. Fueling your body properly is key to running well, minimizing fatigue, and helping with recovery.

That said, fueling up on the wrong foods before a run or not fueling up enough can cause stomach cramps or lead to the dreaded “wall” — a phenomenon where legs become heavy and energy levels plummet.

Here are some guidelines on how to fuel your run with the right meals and snacks.

What to eat before a run depends on how long you’ll be running. Distance runners typically need to fuel up with carbohydrates, protein, and healthy fats for up to 2 days before a run.

“Carb loading” means eating more carbs with each meal than usual so the body’s carbohydrate stores are fully topped up. The body stores carbs as glycogen, mostly in the muscles and liver. It turns to these stores for energy during a long distance run.

For runs less than 90 minutes, carb loading means eating 7 to 12 grams (g) per kilogram (kg) of bodyweight for 24 hours before the run. For runs longer than 90 minutes, this carb loading can span 36 to 48 hours.

If you’re running for less than 60 minutes, carb loading is less important.

Try including pasta, rice, bread, cereal, and potatoes with your main meals. Snacks can include foods like bananas, pancakes, smoothies, and bagels. Carbs from whole grains, fruits, and vegetables have the added benefit of vitamins, minerals, and dietary fiber.

Staying hydrated in the days before a run can help your body perform its best. If your urine is a pale straw color, you’re likely drinking enough fluids to meet your hydration needs.

The pre-run meal serves two purposes. One is to keep you from feeling hungry before and during your run, and the other is to maintain optimal levels of blood sugar for your exercising muscles.

Aim to eat a meal 1 to 4 hours before the run begins. The meal should be high in simple carbs that the body can digest easily. Around 1 to 4 g of carbs per kg of body weight is effective.

Lean proteins, such as poultry, fish, and tofu, can help build and repair muscle and prevent muscle breakdown.

Here are some examples of a pre-run meal:

  • Five scrambled egg whites and one whole egg. Two pieces of white toast with jelly and a banana.
  • One cup (225 g) of low-fat cottage cheese with one cup (150 g) of blueberries. One slice of white toast with a tablespoon of honey.
  • One medium-sized white bagel with two slices of deli turkey and mustard with 30 grapes.
  • One medium-sized baked potato with sour cream and 3 ounces (85 g) of grilled chicken breast with a dinner roll.
  • One cup (200 g) of cooked pasta with 1/2 cup (130 g) of marinara sauce with 3 ounces (85 g) of chicken breast. One slice of lightly buttered bread.

Here are some foods to avoid before a run:

  • High fat foods: Fried foods, heavy sauces and creams, or foods prepared with a lot of butter or oil, digest slowly and can cause a feeling of fullness.
  • High fiber foods: High fiber foods such as whole grains, beans, and cruciferous vegetables like broccoli and cauliflower digest slowly and can cause gas, bloating, and other gastrointestinal symptoms.
  • Spicy foods: Spicy foods can cause indigestion and heartburn.

For adequate hydration, aim to have 500 to 600 milliliters (ml) of water 2 to 3 hours before your run and 200 to 300 ml just before the start.

A pre-run snack consumed 45 to 60 minutes prior provides your body with quick fuel.

It’s only necessary to have a pre-run snack if you intend to run for longer than 60 minutes, but it’s fine to have one regardless of the length of your run.

It serves the same purpose as a pre-run meal by controlling hunger and ensuring optimal blood sugar levels.

A pre-run snack consists primarily of carbs and is much lower in calories than a pre-run meal.

Keep the snack small, as exercising with too much food in your stomach can lead to indigestion, nausea, and vomiting.

Examples of pre-run snacks include:

  • a piece of fruit, such as a banana or orange
  • half a sports energy bar
  • half an English muffin with honey or jelly
  • 15 crackers, such as saltines or pretzels
  • half a cup of dry cereal
  • beverages like sports drinks, coconut water, and smoothies

Limit the same foods you would in a pre-run meal, which include foods high in fat and fiber.

The glycogen stores in your muscles and liver can become depleted within 90 minutes of running. This can lead to fatigue, heavy legs, and the feeling of hitting the wall.

For runs shorter than 60 minutes, you won’t need to snack during the run.

If you’re running for 1 to 2.5 hours, aim to eat 30 to 60 g of carbs per hour spaced 10 to 15 minutes apart.

During longer runs, try consuming 60 to 70 g of carbs spaced 10 to 15 minutes apart.

An intra-run snack can include:

  • Sports drinks: These drinks contain electrolytes, which you lose in sweat, and a high percentage of carbs to restore energy.
  • Energy gels: These concentrated sources of carbs contain sugar and other ingredients like electrolytes or caffeine. They come in small, single-serve disposable packets.
  • Energy bars: These tend to be high in carbs and moderate in protein. Protein helps your muscles recover and rebuild.
  • Other snacks: Dried fruit, packets of honey, gummy bears, and other candies work just as well as their more expensive counterparts at restoring energy.

Regardless of your intra-run snack of choice, make sure it’s something you can take on your run or will be available to you during a race.

Aim to drink 200 to 300 ml of water or a sports drink every 10 to 20 minutes during a run. If you’re sweating a lot, you can take on more fluid, but be careful not to overdo it and risk overhydration.

When it comes to fueling your runs, make sure to experiment with what works best for you.

For instance, you may find that white rice, instead of a baked potato, sits better on your stomach for your pre-run meal.

Or you may notice that eating a banana for your pre-run snack doesn’t give you stomach cramps during your run, whereas an apple does.

Training runs are the best time to experiment with different foods to see what works best for you.

Never do anything new on race day that you didn’t do in practice because you risk not knowing how your body will react to that change.

Nutrition for runners at-a-glance

Here’s a quick summary of how to fuel your body before a long-distance run:

During the 2 days before the run

  • Eat meals and snacks with extra carbs. Aim for 7 to 12 g per kg of body weight.
  • Try pasta, rice, potatoes, bread, bananas, pancakes, smoothies, and bagels.

2 to 4 hours before the run

  • Eat a meal high in simple carbs with moderate protein.
  • Try pasta with a simple sauce or a rice-based dish.

45 to 60 minutes before the run

  • Eat a snack with simple carbs, such as fruit, half an energy bar, or toast.

During the run

  • Consume 60 to 70 g of carbs per hour spaced 10 to 15 minutes apart.
  • Try sports drinks, energy gels, or gummy bears.

Any endurance activity requires special attention to nutrition before and during the event.

Fuel up on high carb, moderate-protein meals 2 to 4 hours before a long-distance training run or event.

In the 45 to 60 minutes leading up to a run, stick with a light, high carb snack.

For runs lasting longer than 60 minutes, make sure to fuel up with sports drinks or other snacks during the race.

Keep fat and fiber intake low in the pre-run meal and snack to ensure adequate time for digestion and absorption.

It’s important to experiment with different foods and beverages during training runs to see what fueling strategy works best for you.