How We Burn Calories

This week, expert bariatric surgeon, Dr. Mark Fusco, Medical Director of the LifeShape Advanced Bariatric Center of Florida, wrote an interesting article about how the body burns calories. Dr. Fusco explains that calories are burned through three ways: Basal Metabolic Rate, Thermic Effect of Food, and Activity Associated Thermogenesis.

The first type of calorie burner is Basal Metabolic Rate, which represents the calories expended to maintain the functioning of the body – to keep the heart pumping, the lungs moving air, and the organs properly working. For the average person, Basal Metabolic Rate accounts for about 60% of their calories burned. Dr. Fusco points out that when people gain weight in the form of fat, it does not substantially increase their Basal Metabolic Rate. Rather, when you gain fat mass, the extra fat is placed in existing cells. Therefore, the only way to change Basal Metabolic Rate for the long run is by increasing muscle mass.

The second type of calorie burner is the Thermic Effect of Food, which is, simply put, the calories burned in order to digest what is consumed. The Thermic Effect of Food is responsible for a very small amount of calories burned and is rather fixed.

Activity Associated Thermogenesis, the final way that we burn calories, is the most variable, but for the average person is responsible for burning about 30% of total calories expended. It is also the method that we have the most control over. Activity Associated Thermogenesis is separated into two components. The first is purposeful exercise, such as sports, running, and swimming. The second is what is called “Non Exercise Associated Thermogenesis” or “N.E.A.T.”, which is responsible for the calories burned through daily activities that we do on an almost subconscious level. Some of these activities include fidgeting, walking, stretching and chewing gum. These are activities that burn calories at a considerably low rate, but if done over long periods of time, will account for a substantial number of calories burned.

Dr. Fusco referenced a study that found that when the participants’ food consumption was increased, some participants subconsciously increased their N.E.A.T. and gained little weight, while others didn’t increase their N.E.A.T, and gained a large amount of weight. He said that it is unclear why some people subconsciously increased their N.E.A.T. and others didn’t, but that there may be a genetic factor involved.

Some of the suggestions made by Dr. Fusco to increase N.E.A.T are to: walk whenever you can, take the stairs instead of the elevator or escalator, and think about getting a standing desk at work. You can read more about the ways we burn calories, view graphics associated with this research, and see Dr. Fusco’s complete list of suggestions to rev up calorie expenditure here.