Energy Expenditure

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Calories in vs. calories out”.“Calorie deficit”. These phrases are used over and over again. Without knowing the basics of energy expenditure, these phrases mean little to nothing. So, what are the calories we eat used for? I’m going to go over the basics and describe the various components of how your body uses the calories you eat.

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First, let’s get familiar with the term total daily energy expenditure (TDEE). TDEE, in simple terms, is the amount of calories your body uses each day. There are multiple different components that make up your TDEE. And whether you’re working toward specific body composition goals or are just wanting to learn more about energy expenditure, knowing more about each of these components can help you maximize your strategies around energy expenditure. With that being said, TDEE is made up of four different parts: basal metabolic rate (BMR), thermic effect of food (TEF), exercise activity thermogenesis (EAT), and non-exercise activity thermogenesis (NEAT). Now, I know that’s a lot of acronyms, but stay with me. We are going to break each of these down. 


BMR is the amount of energy (or calories) it takes to maintain basic, life-sustaining functions. It is the largest component of TDEE. Therefore, focusing on optimizing your BMR is a smart move if you’re hoping to make changes to your body composition. There are multiple factors that affect your BMR. Muscle mass is one of them. The more muscle mass you have, the higher your BMR will be, and vice versa. How much you’re eating also plays a large role in your BMR. Undereating will have a negative effect on BMR, whereas ensuring you’re eating sufficient calories will have a positive effect. Also, getting caught in the “lose, gain” cycle of body weight will result in a negative effect on your BMR. 


TEF, put simply, is the amount of energy needed to digest the food you eat. How can you increase TEF? First and foremost making sure you’re eating adequate calories is key. The more food you eat, the higher your TEF will be. Second, focus on eating sufficient protein and carbohydrates. It takes more energy to digest protein and carbohydrates than it does to digest fat. While we’re here, I also want to quickly discuss a common myth about TEF. It is often thought that eating smaller, more frequent meals will increase TEF and therefore increase TDEE. However, this has been disproven. This is because the TEF for X amount of calories is the same whether that X amount of calories is eaten in 2 or 6 meals. So, eat the amount of meals that works for you and your lifestyle!


EAT is the amount of energy used during planned physical activity, such as workout. Though many people are led to believe that exercise is a much larger contributor to TDEE, as you can see by the graphic, it is actually the smallest contributor. Yes, exercising for longer amounts of time or increasing the intensity of your workout will increase EAT. However, due to the fact that it has a smaller contribution to TDEE, it should not be your priority if you’re wanting to maximize your TDEE. 


NEAT is the amount of energy you use to perform any activity that is not structured exercise. Think walking to your car or climbing the stairs. NEAT is the second largest contributor to TDEE and the great part is, small lifestyle changes can greatly affect NEAT. Finding simple ways to increase your NEAT is a great and easy way to increase your TDEE. Here are a few ideas on how to increase NEAT. 

  • Park at the back of the parking lot
  • Use the stairs instead of the elevator
  • Set a daily step goal 
  • Take a frequent stand or walk breaks if a majority of your day is spent sitting
  • Participate in active hobbies
  • Do the chores (vacuuming, mowing, cleaning)

So those are the basics of energy expenditure and a few ideas on how to maximize each of these components. Again, BMR is the largest component of TDEE and therefore maximizing this should be a focus for those wanting to increase energy expenditure. And increasing your daily NEAT is a simple way to increase energy expenditure. Some overall takeaways are to lift heavy (build up that lean muscle mass), eat an adequate amount of food every day, and get your body moving!

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