Is it better to eat breakfast before or after a workout?

Ask Shannan: is it better to eat breakfast before or after a workout?

Let’s begin this discussion by stating the obvious, the answer to this question pertains primarily to workouts that are performed in the morning.

The best time to exercise is whenever you make time in your schedule. If that time is in the afternoon, then I wouldn’t change your routine just yet.

Exercise, regardless of whether you are in a fed or fasted state, offers many health benefits. These benefits include reduces blood sugar, reduces blood pressure, increases insulin sensitivity, strengthens muscles and heart, increases blood circulation, helps with digestion, and is the single best health intervention for longevity that you can do.

Eating Before a Workout

Eating before a workout can provide a ready source of energy, especially if the snack or meal contains carbohydrates.

For high intensity or short duration exercises (<45 minutes), carbohydrates are the primary fuel source for the muscles.

If you are doing a prolonged workout (>60 minutes), you can exercise in a fasted state. Research suggests that for optimal or peak performance in a prolonged workout, have a snack first. Eating before a prolonged workout will supply the body with an energy source from food, instead of the body’s stored form of energy.

Understanding Stored Energy for Exercise

The body stores energy primarily in two ways 1) stored carbohydrates in the form of glycogen in the liver (100-120 grams glycogen) and muscles (400-500 grams glycogen) and 2) stored fat in the form of body fat.

While you sleep, liver glycogen is already depleted 60-80%.

The “bonk” or “crash” feeling you get during fasted exercise is the liver depleted of glycogen, which results in a decrease in blood sugars. The body then needs to tap into stored body fat, as well as muscle glycogen for energy.

As you become more fat-adapted, the body will get used to exercising in a fasted state, which will help with that crash feeling. This does take some time and practice.

Eating After a Workout

Do you exercise in the morning? You may want to consider incorporating fasting workouts into your routine.

I like to think of exercising in a fasted state like exercise 2.0. Fasted exercise has all the same benefits of exercising in a fed state and then some.

Fasted exercise relies on stored glycogen and fat as the primary fuel sources. This can be good news if your goal is fat loss.

All types of exercise help to lower blood glucose levels and improve insulin sensitivity. Performing exercise while fasting relies on fat as a fuel source, this offers a more powerful increase in insulin sensitivity. There is also evidence to suggest that there is an enhanced production of human growth hormone, which is a natural response to exercise.

Lastly, nearly all the studies examining fasted exercise conclude that there are enhanced metabolic adaptations in the muscle. Exercise is a type of stressor. It places a stress on the mitochondria (energy powerhouse) of the cell. Fasted exercise increases the number and function of the mitochondria.

What’s the bottom line? Try a fasting workout to optimize metabolic benefits. If you are about to perform a prolonged workout or endurance workout, have breakfast first.

Struggling to find a workout routine? Check out these 5 ways to fit in fitness.

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Hi, I'm Shannan.

I help adults make confident choices for a lifetime of good health.


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