Dr. Thomas Dwan - Is It Bad For You? Approved by Dr. Thomas Dwan

Is Working Out Before Breakfast Bad For You?



Short answer

To put it simply, working out before breakfast is not bad for you. Latest studies indicate that more fat is burned when you exercise before breakfast.



Long answer

The debate regarding exercising before breakfast or after has been going on for eons, and it is no wonder because the case can be argued convincingly both ways. This is because in certain situations it is better to exercise on an empty stomach, while in others eating a small meal is more beneficial. While research on the subject is limited, the most recent studies that have been done indicate that exercising before breakfast can actually be of benefit under certain circumstances.

If your intent is to build strength or enhance speed and endurance, then exercising without fueling your body probably won't serve you well. The lack of energy will be detrimental to the body’s ability to perform at its optimal level. On the other hand, if your goal is to lose weight, then mounting evidence indicates that cardio or aerobic exercises done on an empty stomach early in the morning are advantageous.

There are a number of reasons why working out before breakfast can prove to be of benefit. To start with, when your body has been deprived of food for around 8 hours during the night, your glycogen levels are depleted so when you exercise before breakfast, the body is forced to burn more fat. Additionally, morning exercise increases metabolism from a minimum (during the night long resting phase) to a maximum (during exercise). The effects of this increased metabolism continue long after the exercise session is over. This advantage is lost if you exercise in the evening, where the metabolic rate drops drastically when you go to sleep.

The role of hormones also influences weight loss. After a meal, the body releases the hormone insulin, which works by inserting blood glucose into the cells for use as energy. Research indicates that exercising on empty stomach enhances insulin sensitivity, so when you do eat the movement of glucose into the cells is easier. This cuts down on the amount of glucose being stored as fat. A second hormone called the Growth Hormone not only facilitates utilization of fat, but also stimulates muscle building and metabolism.

Finally, it is important to remember that everyone is different. If you can’t sustain your morning workout for a sufficient length of time because you simply have no energy, then working out before breakfast may not be the right choice for you. 

Possible short-term side effects

  • low levels of energy
  • tiredness / weakness
  • low sugar levels (high intensity workouts)
  • use of muscle protein for energy


  • increased fat burning

Healthier alternatives

  • eat a healthy, lightweight meal prior to exercise

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Written by Desmond | 07-01-2016

Written by Desmond
Suggest improvement or correction

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