Skip Breakfast Before Exercise

A new study published in The Journal of Nutrition finds that skipping breakfast before working out changes our relationship with food for the rest of the day, often in surprising ways.

When we eat breakfast before exercising, our bodies use those carbohydrates as the primary source of energy instead of our stores of fat – this is the basis for the ketogenic diet. Like the keto diet, researchers found if we skip breakfast completely before working out, we have no calories to burn from a meal and our bodies must instead rely on internal carbohydrate stores, along with some of our fat.

To reach this conclusion, researchers studied a small group of men in a laboratory setting, monitoring precisely calorie intake and exercise.

  • The participants who ate oatmeal without working out had a daily energy surplus.

  • Those who ate and then worked out burned and consumed the same number of calories that day – essentially a net balance of zero.

  • And those who skipped breakfast were super hungry at lunch, but ended the day with a calorie deficit (after eating as much as they wanted).

This is great news! If we work out on an empty stomach, we have a reduced appetite later in the day, burning more fat and consuming fewer calories – this inevitably leads to weight loss when sustained as a habit.