Rose Mattson, RD

What to eat before a workout

rose mattson - what to eat before a workout

“What should I eat before I workout?”

This is a common questions as there is a lot of confusion about what to eat before a workout or athletic event. What most people don’t realize is that, carbohydrates are our friends.

Let’s do a little background.

Carbohydrates, or carbs, are foods such as bread, crackers, pasta, rice, fruits, veggies, dairy products, and legumes. When you eat carbs, they are digested and absorbed as glucose and then either burned for energy or stored for later use. Carbs are stored as glycogen in your muscles and liver, which is essential for energy during exercise.

Carbs are your primary and most efficient fuel source during exercise. Without enough carbohydrate, your performance will suffer. Likewise, if you do not refuel your glycogen stores (ie carb stores) after exercise, you will have a harder time recovering and rebuilding after a tough workout.

I repeat, carbs are our friends.

What to eat before a workout:

Tip #1: drink water prior to moving 

The recommendation for water is: 5–10 ml/kg of body weight within 2-4 hours prior to exercise. This mean if you weigh 140lbs or 64kg, you will need about 320-640 mL, or about 1.5-3 cups, of fluid in the 2-4 hours prior to your exercise bout. Math sucks, but I believe in you.

Another good indication of your hydration is the color of your urine. (Side-note: since about halfway through grad school, I started talking about pee and poop with people, and since I routinely talk about it now, it feels totally normal. So if we have conversations about your pee, this is normal). Anyways, a good indication of how hydrated you are is the color of your pee. You are probably too hydrated if your pee is clear, and dehydrated if it is closer to brown. We want to shoot for a light yellow color. This is highly individual for everyone, so it may take some playing around with to get it just right.

Tip #2: shoot for a carbohydrate-rich snack prior to exercise

Carbohydrates should be consumed at 1–4 g/kg of body weight, 1-4 hours prior to exercise. If you need to eat prior to practice but only have one hour in order to do so, you should aim for 1g/kg of body weight at that hour period. For example, if you weigh 64 kg (140lbs), you will need 1g/kg of carbohydrate prior to exercising in an hour. This equates to 64 g of carbohydrate which is about two pieces of toast with 2 tablespoons of jam with a banana.

Good choices for carbs before exercise are low-fat, low-fiber, and low(er)-protein. You may need to try several options before settling on your favorite.

So what does this look like? Here are some examples:

If you are someone who would prefer to eat a meal before an event, try and eat 3-4 hours prior. The same carbohydrate recommendations still apply and make sure you consume a protein source.

If you are someone who rolls out of bed and into the gym, still try having something small. A banana, or a piece of toast before hitting your workout may help you feel better throughout.

Remember, everyone is highly individual. What works for others may not work for you and it may take some trial and error to find out exactly what works best for you. 

Tip #3: consider adding some protein to your meal prior to your workout

There is some research to suggest that a moderate amount of protein before exercise, about 10g, may contribute to muscle protein synthesis (ie may help build muscle tissue). If protein sits well in your stomach prior to exercise, this can be something to consider. Look for a low-fat option such as low-fat milk with cereal. That being said, the most important thing is to get protein after exercise!

Other notes of advice:

If you find yourself with low energy and fatigue during your workout, check in with yourself.

Fat slows down the digestion and absorption of our foods, which means that the carbohydrate you ate will take longer to get to your muscles. This may decease your ability to perform at a high level.

Being dehydrated during your workout can decrease your performance up to 2%! This may not seem like a lot, but has significant impact during the last few minutes of your workout.

To Recap: 

Drink enough water

Eat carbohydrates before exercise 

Consider adding some protein to your meal before you exercise 

As always, let me know if you have any other questions! I love this stuff.


Nancy Clark’s Sports Nutrition Guidebook 5th edition

Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance 2016.

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