By Michael Ormsbee, PhD, Florida State University

Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily

Are you following a diet and/or exercise plan but still falling short on your goals? Professor Ormsbee describes all the components that go into burning calories.

Total Energy Expenditure

Once you understand how to calculate energy expenditure, or the calories used for rest and activity, you need to consider how this fits into the energy balance equation. Energy balance is where the food calories that you take in match the calories that you expend or burn. Thus, the next step is to consider and evaluate the major components of all of the calories that you burn in a day, or total daily energy expenditure.

Total daily energy expenditure is made up of four components: your resting metabolic rate; thermic effect of food (the amount of energy required to digest the food you eat); thermic effect of activity (the energy expended doing active things like working around the house or doing structured exercise), and your non-exercise activity thermogenesis or NEAT, which includes unplanned activity like tapping your feet or bouncing your knees.

Of the components of our total daily energy expenditure, by far the largest one is your resting metabolic rate. Resting metabolic rate is defined as the energy required to maintain the systems of your body at rest. 

About 60% to 80% of the oxygen you consume and the calories you burn goes to just keeping you alive at rest. For very active people, resting metabolic rate may make up less of their total energy expenditure as a percentage because physical activity likely makes up a much larger portion of total energy use in the day. 

Many factors influence resting metabolic rate including age, sex, genetics, energy intake whether fasted or fed, body size, lean body mass, body temperature, the climate that you’re in, caffeine or nicotine consumption, and exercise. Clearly some uncontrollable characteristics play a part in determining this figure.

Thermic Effect of Food and Activity

The second component of total daily energy expenditure is the thermic effect of food (TEF), which is defined as the energy required to digest, absorb, transport, metabolize and store your food. Huge meals with high-calorie counts have a larger TEF. We also know that protein-rich foods also have the greatest effect on increasing calorie burn as they are the most difficult to digest and absorb—which is one reason adding protein in the diet can be helpful for body composition.

Finally, the last components of your total daily energy expenditure are the thermic effect of activity (TEA) and non-exercise activity thermogenesis, or NEAT. These include the energy cost of daily activities including planned exercise, walking to work, or taking the stairs and involuntary muscular activities like knee bouncing, toe tapping, or fidgeting. 

Obviously, the amount of exercise and activity you do will determine how much of a role TEA or NEAT plays into your overall energy expenditure. For most people who do not exercise much at all, then TEA might make up 10%–15% of your total daily energy expenditure. If you are really exercising a lot, though, this figure could be upwards of 30%. 

Exercise and Metabolism

You’ve probably also heard that exercise will increase your metabolism. Well, it will definitely increase oxygen consumption, and it can do so for a few hours up to a few days after you finish exercising if done properly. 

Interestingly, if you exercise regularly for a few weeks or years and then stop for some reason for an extended period of time, your resting metabolism can also decrease. In fact, one study showed that after collegiate swimmers stopped swimming for five weeks, they had a significant 7% decrease in resting metabolic rate. Thus, it is important to maintain your great exercise habits for life.

Now that you understand the energy balance equation, identify one or two habits in your lifestyle that you can modify to improve one of the aspects of your energy balance. In fact, energy imbalances like eating even just slightly more calories than you expend can translate to significant weight gain over time. 

Usually, this is how weight gain sneaks up on us, and it’s just not noticeable when the weight gain is five pounds over the course of an entire year. In five years, though, this is 25 pounds of extra weight.

It is also important to understand that your body will typically fight to be in energy balance and will make adjustments without you even knowing it. This is why weight gain and weight loss typically stall or plateau over time. 

While individual foods definitely impact our metabolism, weight, and body composition, the bigger picture includes an overhaul of the energy balance equation including food quality and food quantity and the exercises that we choose to take part in. The good news is that most often when you choose to eat higher quality foods, the food quantity piece of the energy balance tends to regulate itself.

This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.