Carbohydrates are an important food for exercising, what and when to eat for exercise

Fuel your body: what & when to eat before exercise

What you eat before exercise can make or break your session. From your cognitive to your physical performance, eating the right foods to fuel your body has an incredible impact on what you can accomplish.

Eating with your workout in mind can help prevent injuries, support your muscles post exercise and help you feel great. When you give your cells the right nutrition, you help them perform, repair and deliver energy.

What to eat? When to eat before exercise? Should you workout on an empty stomach? Let’s dive deeper into some of the most common questions when it comes to eating to fuel your body for effort. By the end of this article, you will know what foods to eat and when, and which foods to avoid before exercise.

Why is food important for your fitness? 

What you eat before exercise, and even during or after, impacts your performance and wellbeing during your workout session. When you run on empty, your body is using whatever energy storage it can find, but it’s not necessarily the extra fat you’re trying to get rid of. 

Eating foods that boost your energy at the right time, such as energy bars, snacks, drinks or gels filled with carbohydrates, is a great way to get that energy without taxing your digestive system.[1]Marriott BM. The Functional Effects of Carbohydrate and Energy Underconsumption. Not Eating Enough: Overcoming Underconsumption of Military Operational Rations. Washington, D.C.: National Academy … Continue reading However there’s more to it.

For your best performance, you need to understand your energy consumption and your body’s biochemistry process. At the beginning, you need a quick supply of energy. That’s something your body gets best from quality carbs, which it turns into glucose. After that, you need to build reserves for endurance, so your body turns your glucose reserves into glycogen that will keep you going for longer. Post workout, you can help your recovery and get ready for your next exercise session by replenishing your glycogen level.

What are your nutritional needs?

In addition to the type of effort, intensity and duration you are planning for, there’s a number of physiological factors that influence your nutritional needs. You can structure your eating plan accordingly, but a lot of it is also going to be some trial and error.

When you have a full day of physical activity or if you are competing, as with a marathon, your eating plan should account for your nutrition before, during and after your workout. For some sports, you’re going to burn energy very fast, while other activities can require a constant supply of energy for longer endurance.

With our age, fitness level… We all have slightly different energy needs and burn rates, but here’s a basic guideline to start from.

What you need to eat based on your workout length:

  • If you’re exercising less than 45 minutes: 
    Plan for a snack 30 to 60 minutes before. Dried fruits, nuts or an energy bar are options that won’t weigh you down. Have some water available during the session. Afterwards, have a snack that includes mostly carbs and a little protein, a 3:1 ration works well.
  • Preparing for a 1 to 2.5 hours endurance workout: 
    Whether it’s with energy bars, nuts or gels, try to get 30 to 60 grams of carbs per hour. This should enable your body to convert enough glucose to glycogen to keep your muscles fueled. 
  • Preparing for a full day of endurance:
    Your body is going to need more glycogen, so aim for 60 to 90 grams of carbohydrates per hour. 

Related: Can you skip warming up before working out?

Meal planning for your workouts

How much, what and when to eat before exercise is different for each athlete. With experience, you can find what works best for you.

As a general guide:

  • Large meals: have a real meal 3 to 4 hours before your workout.
  • Small meals or snacks: get some carbohydrates 1 to 2 hours before your session. Try a healthy snack or energy drink with a lot of carbs.
  • Post exercise: within an hour, eat some carbs and protein to replenish your energy reserves and help your muscles recover. Aim for 1 gram of protein for 3 grams of carbs. An energy bar high in carbs, full grain bread with peanut butter, fruits and yogurt or a protein shakes are all good options.

Is it OK to workout on an empty stomach?

When it comes to exercising with an empty stomach, or fasted training, there’s different schools of thought on the topic.

Fasted cardio doesn’t help weight management

Some trainers recommend fasted cardio as a way to burn fat quickly. This doesn’t involve fasting for a fixed amount of time, but simply to perform your cardio in the morning before having any food.

A few studies show that physical exertion after 8 to 12 hours of fasting while sleeping can help oxidize, or burn, up to 20% more fat.[2]Bachman JL, Deitrick RW, Hillman AR. Exercising in the Fasted State Reduced 24-Hour Energy Intake in Active Male Adults. J Nutr Metab. 2016;2016:1984198. doi:10.1155/2016/1984198 On the other hand, other research shows that it makes no difference for fat loss in the long run.[3]Melanson EL, MacLean PS, Hill JO. Exercise improves fat metabolism in muscle but does not increase 24-h fat oxidation. Exerc Sport Sci Rev. 2009;37(2):93-101. doi:10.1097/JES.0b013e31819c2f0b That’s because the rate at which your body burns fat and overall fat loss are two different phenomena.

Eating or working out first? It depends…

In the end, whether you choose to exercise with an empty stomach depends on your objectives, length of training and how you feel.

Your fitness objectives

If your objective is to build muscle and strength or develop power and speed then you should nourish your body with your overall eating plan. A body that is given all the nutrition it needs performs better. Furthermore, as we saw above your body needs carbohydrates for energy production and storage.

Your workout length

Nevertheless, if your workout lasts less than an hour you don’t need to worry about glucose depletion. A meta analysis of 23 studies showed that there’s no significant energy difference between fasted versus fed cardio [4]Aird TP, Davies RW, Carson BP. Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis. Scand J Med Sci Sports. … Continue reading

It depends on the athlete

There’s no proscription to working out without eating first. Whether you lack time in the morning or enjoy the feeling of working out on an empty stomach, that’s up to you. Just be mindful of keeping your session under an hour and to listen to your body. If you start feeling faint or dizzy, or that you’re running out of energy, cut your training short. If that’s the case, instead of fasted training, have a few dates or almonds before your next workout. So it’s not the end of the world if you choose to train fasted, just make sure you have a post-workout meal with enough carbs and protein to replenish your energy stores and help your muscles recover.

Is fasted exercise bad for your muscles?

There’s a common concern that exercising in a fasted state can lead to shedding muscle. This scenario would only be a possibility if your body had used your glycogen reserves and for most people that would require intense exercising for several hours. Yet, you’re more likely to run out of steam faster, resulting in improper form and increasing your risk for injury.

What foods to eat before exercising?

Since glucose is the best energy source when working out, select foods high in carbohydrates while still easy to digest. For example, pasta, fruit, whole-grain bread or cereal, energy bars or drinks are good energy sources.

However, not all carbs are made the same and result in a different blood sugar rate. For an endurance workout, choose carbs with a low glycemic index (GI). These types of carbs won’t raise your blood sugar too quickly and will maintain your glucose level stable for longer.[5]Yalçın T, Al A, Rakıcıoğlu N. The effects of meal glycemic load on blood glucose levels of adults with different body mass indexes. Indian J Endocrinol Metab. 2017;21(1):71–75. … Continue reading Think of oatmeal, dark rice, or whole grain foods.

On the other hand, for workouts requiring a short energy outburst choose foods with high-GI. That means foods that will raise your blood sugar quickly, such as foods made with refined grains like white bread or pasta.

What & when to eat before your workout?

These lists are just a guide to give you some ideas. Test what works for you to make you feel healthy and energized.

Time pre-workout: 3 to 4 hours

  • Whole-grain bread
  • Whole-grain cereal with low fat milk of your choice
  • Whole-grain pasta
  • Brown rice with veggies
  • Sandwich on whole-grain bread with meat or cheese
  • A mixed salad with some lean protein and whole-grain bread roll
  • Baked sweet potato with just a little cheese and plenty of veggies
  • An omelet or eggs with veggies and whole-grain crackers or bread

Time pre-workout: 2 to 3 hours

  • Whole-grain bread, crackers or pasta
  • Fresh fruits
  • Oatmeal
  • Yogurt
  • Fruit or high-carb smoothies

Time pre-workout: 1 hour or less

  • A handful of nuts and dried fruits
  • A piece of fresh fruit
  • Sports drink (1 to 1/2 cup)
  • Energy gels or bars

Related: Lactic acid vs lactate: why are muscles sore after working out?

Meal planning for your workout schedule

What to eat if you exercise in the morning?

Plan to have at least an hour between eating your breakfast and exercising, giving your body enough time to digest and convert carbs to glucose. If you don’t have an hour, eat a lighter breakfast or have a sports drink or smoothie. 

If you plan on an intense workout, choose foods with more carbs to sustain your energy needs.

Great breakfast options before exercising:

  • Whole-grain bread
  • Whole-grain cereal with low fat milk of your choice
  • Yogurt with fruits
  • A banana
  • Peanut butter (choose one without extra salt and sweeteners)
  • Fruit smoothie
  • Granola bar
  • Energy bar

What to eat if you exercise in the evening?

If your session is at the end of the day, make sure your lunch will have enough carbs while being low in fat and fiber. You want foods that will give you energy while being easily digested, so as not to get sluggish.

Having a well balanced nutritious meal is always a good idea. Before working out, plan a lunch with plenty of carbs and protein as well as a snack.

Great lunch options before working out:

  • A sandwich with whole-grain bread and protein with a salad
  • An omelet or eggs with veggies and whole-grain crackers or bread
  • Protein of your liking, brown rice or whole-grain pasta, and veggies

An hour before your session, you can have a snack to make sure you don’t get hungry and have enough energy.

Great snack options:

  • Dried fruits and nuts
  • A banana
  • A chocolate milk drink (good 3:1 carbs to protein ratio)

Keep hydrated

Aside from eating right, drinking enough before and after you exercise is also important for your workout. Without proper hydration, your body can’t perform at its best.

When you exert yourself you sweat, losing water and electrolytes in the process. By rehydrating properly you can help your recovery and future ability.[6]American College of Sports Medicine, Sawka MN, Burke LM, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377-390. … Continue reading

If your next workout is within 12 hours make sure you drink enough to replenish. If you exercise for more than an hour, have a sports drink rather than water to make sure you get enough electrolytes.

How much water to drink for exercising

It’s a good idea not to drink more than a cup or half a cup of water in the hour before exercising. The sensation of a stomach full of liquid bouncing around isn’t very pleasant, nor is a full bladder.

Yet we still need to have sufficient amounts of fluids. The quantity of water depends on your physiology, activity and obviously the temperature around you. 

As a guideline the American College of Sports Medicine recommends drinking:

  • 2 to 3 hours before working out: 2 to 3 cups of water
  • During your workout: ½ cup to 1 cup of water every 15 to 20 minutes.
  • Post-workout: 2 to 3 cups of water

Foods to avoid before a workout

Feeling heavy or sluggish during your workout because of the foods you ate can easily be avoided. It’s great to have your full meal a few hours before your session but you should also select foods that are easy to digest to avoid feeling bloated or have your body in full digestion mode.

Having a big juicy burger is probably one of the worst lunch meals before a workout. High in fat and fiber, it’s harder to digest and stays in your stomach a long time. If you’d go for a speed run that evening, it’s likely you would be slower, or worse could have a hard time keeping your food down.

When the body is digesting, your blood is busy delivering oxygen to your stomach rather than to your muscles.[7]Grundy MM, Edwards CH, Mackie AR, Gidley MJ, Butterworth PJ, Ellis PR. Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial … Continue reading When you’re working out, that can lead to cramps, stomachache and nausea. So stay away from that burger, or for that matter any foods high in fat and fiber, such as doughnuts, candy bars, or fries.

Key takeaways

  • For performance, endurance and post-work healing your body needs the right nutrition. That includes a lot of carbs and some protein.

  • What to eat: get some whole-grain carbs in your meals. Your body will use these high quality carbs to make glucose and glycogen reserves for energy.

  • How much to eat: it depends on the amount of time you have to let your body digest. You don’t want to feel sluggish when exercising and your body needs enough time to process the nutriments.

  • When to eat: it depends on when your next workout session is scheduled for. If you have an hour or less, you should have a light snack.

  • Your meal plan should include your full meal, snacks and post workout food according to your nutritional needs.

  • If you feel good working out on an empty stomach, then there’s no contraindications for shorter, less intense sessions. If your goal is to build strength and muscle or become stronger and faster, then it’s best not to exercise in a fasted state.

  • Don’t forget to keep hydrated all day long. An hour before your workout, limit yourself to a cup of water.

  • Avoid meals high in fat and fiber that are harder to digest before your workout.


*Be mindful about your health. This article is provided for informational purposes only, and does not intend to substitute professional medical advice, diagnosis, or treatment.