What and When to Eat Before Exercise

Strategies to Build and Maintain Energy Reserves

Girl eating oatmeal with berries

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The food you eat before, during, and after a workout can not only affect your performance but your comfort, as well. Eating the right energy foods at the right time—including energy bars, drinks, gels, and other easily digestible carbohydrates—can provide you with the energy resources you need without overtaxing your digestive system.

To perform at your peak, you should stage the foods you eat. That means focusing on quality carbs which your body can convert into glucose for immediate energy, the reserves of which are converted into glycogen for future use. After exercise, you need to replenish your glycogen stores to aid in recovery and be ready for your next workout.

Calculating Your Need

You need to structure your eating plan based on the intensity, duration, and type of workout you intend to do. This is especially important if you are competing in an all-day event, such as a marathon, track meet, or team sporting event. Some activities burn energy rapidly, while others require a slow and steady fuel supply to keeping you going for the long haul.

To this end, it is important to know how much energy you will likely expend during the activity:

  • If the workout is less than 45 minutes, you may only need a snack beforehand, water during the workout, and a snack afterward.
  • For endurance exercises of one to three hours, aim for 30 to 60 grams of carbohydrates per hour. This will provide ample carbs to supplement your muscle glycogen reserves during exercise.

General Guidelines on What to Eat Before Exercise

Eating before exercise is something only the athlete can determine based upon experience, but, as a general guideline:

Pre- and Post-Exercise Strategy

To prepare for your workout, you need to replenish your glycogen stores upon waking since you will be in a fasted state. You should do so well enough in advance of the activity so that you don't work out on a full stomach. Depending on how much food you eat, allow yourself anywhere from one to four hours to properly digest the pre-exercise meal.

If you have an early-morning event, it is best to get up as early as possible to start your eating plan. If you are unable to do so, eat or drink an easily digestible carb source no more than 20 to 30 minutes before the event. Clearly, the closer you are to the start of the event, the less you should eat. If you fail to fuel up at all, you risk unintended ketosis (the build-up of ketoacids in the blood), leading to rapid fatigue, muscle cramps, and increased heart rate.

Within an hour of completing a long or high-intensity workout, find an energy food that provides you with 15 to 25 grams of protein. You will also need to consume 1 to 1.5 grams of carbohydrate per kilogram of your body weight per hour for the next four to six hours. This will replenish your glycogen stores as well as promote muscle protein synthesis.

What to Eat

Because glucose is the preferred energy source for most exercise, a pre-exercise meal should include foods that are high in carbs and easy to digest, such as pasta, fruit, bread, energy bars, and energy drinks.

The type of carb you choose also matters. If you're attending an endurance event, go with a carb with a low glycemic index (GI). Low-GI carbs don't raise the blood sugar quickly but rather maintain glucose levels at a steady state for a longer period of time. These include such foods as oatmeal and anything whole grain.

If your activity is short but intense, skip the whole grains and go instead for high-GI refined grains that raise the blood sugar quickly and give you a burst of energy off the starting blocks.

Here are just some of the foods to consider prior to the start of an event:

3 to 4 Hours Before Exercise

  • Fresh fruit
  • Bagels
  • Pasta with tomato sauce
  • Baked potato
  • Energy bar
  • Cereal with milk
  • Yogurt
  • Toast with peanut butter, lean meat, or cheese
  • Water

2 to 3 Hours Before Exercise

  • Fresh fruits
  • Bread, bagels, or pasta
  • Oatmeal
  • Yogurt
  • Water

1 Hour or Less Before Exercise

  • Fresh fruit, such as apples, peaches, or grapes
  • Energy gels
  • Up to 1-1/2 cups of a sports drink

What Not to Eat

Foods with a lot of fat or fiber can be difficult to digest and tend to remain in the stomach for a long time. What this means is the blood meant to deliver oxygen to the muscles will instead get diverted to the stomach. If this happens during exercise, you are likely to experience cramping, stomachache, and nausea. As a rule, avoid foods like doughnuts, fries, potato chips, candy bars, or red meat.

While beans, dried fruit, coleslaw, and dairy may fit the bill nutrition-wise, you may want to skip them and other potentially gassy foods prior to exercise if you are prone to bloating.

The same applies to caffeine. While a cup of coffee may offer you a burst of energy at the start of an event, the "energy" is due to the stimulating effect of the drug on the central nervous system. Caffeine offers nothing in the way of fueling your muscles or building your glycogen stores. What it can do is lead to rapid dehydration due to its diuretic effect, resulting in fatigue, headache, muscle tremors, and nausea.

Before a workout, skip any foods that are difficult to digest (high fiber or high-fat foods) or low in nutrient value, such as fried foods, candy, and caffeine.

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Article Sources

  • Kanter, M. High-Quality Carbohydrates and Physical Performance: Expert Panel Report. Nutr Today. 2018;53(1):35-9. DOI: 10.1097/NT.0000000000000238.