When thinking about the number of calories we burn daily, we must look at our metabolism in its entirety. We can’t just look at caloric expenditure through the lens of a 1-hour formal exercise session. We must account for the other 23 hours in the day. In this article, we will discuss the 3 components that make up our total daily energy expenditure or TDEE.
1. Basal Metabolic Rate
Your Basal Metabolic Rate or BMR makes up most of your total daily energy expenditure. Depending on the individual, BMR accounts for about 50-70% of calories expended per day. These are the calories that it takes for us to essentially stay alive. Our organs, hearts, lungs, and various other parts of our bodies requires a certain number of calories to sustain life. In other words, BMR is the number of calories you would burn in 24 hours if you were resting in bed all day.
BMR VS RMR
Basal Metabolic Rate is commonly interchanged with Resting Metabolic Rate or RMR. There are a lot of similarities between BMR and RMR, but there are some differences too. BMR is the number of calories you would be burning if you were bed ridden for example. RMR is the number of calories you would be burning if your lifestyle was completely sedentary. For example, if you work a desk job, don’t formally exercise, and move very minimally throughout the day you would be utilizing your resting metabolic rate. The energy burned through RMR is significantly higher than the energy burned through BMR.
2. Physical Activity
Physical activity accounts for about 20-30% of your total daily energy expenditure. This could be activity such as daily aerobic exercise or intense strength training 3 -6 days per week. For example, if you are a person completely new to resistance training and your body requires 2000 calories per day to maintain your weight, strength training 3-5 days per week can increase your maintenance calories by about 20%. Therefore, your new daily maintenance calories would be 2500.
NEAT VS EAT
A lot of people only think of exercise in terms of a 1-hour weight training session or a 45-minute cardio session. The random movement you do within the other 22-23 hours of the day also adds to your caloric expenditure. This is called Non-Exercise Activity Thermogenesis or NEAT. You can also think of it as the number of calories you burn through out the day from activity that is not considered intentional exercise. The calories you burn randomly throughout the day far exceeds the calories you burn in the gym. The calories you expend from structured physical activity is called your EAT, which stands for Exercise Activity Thermogenesis. If you really want to maximized fat burning, you want to main a high level of NEAT.
Some of the best examples of Non-Exercise Activity Thermogenesis are:
- Working physically demanding jobs, Ex (construction workers, waiters, package delivery people)
- Walking for an hour a day
- Parking further away in the grocery store parking lot
- Taking the stairs to the office instead of the elevator
- Being involved in a dance community
- Playing leisure sports
- Doing household chores on a Saturday
3. Thermic Effect of Food
Digestion plays a role in our total daily energy expenditure. Our bodies require a certain number of calories to break down food energy. This process is known as the Thermic Effect of food or TEF. It is responsible for about 10% of the calories we burn daily. For instance, if you are a 180-pound male that requires 2700 calories to maintain your weight, you are burning roughly 270 calories through digestion alone.
Macro-nutrients and TEF
How fast our bodies break down food into energy is dictated by the macro-nutrient composition of our diets. Out of all three macro-nutrients, your body takes the longest to digest protein. It has the highest thermic effect and is your most satiating macro-nutrient, which is why higher protein diets are so heavily promoted in the fitness industry. If your goal is fat loss, you must sustain a net caloric deficit long enough to lose the fat you want to lose. Sufficient protein intake paired with a proper strength training program ensures the weight you lose is fat and not lean body mass. Dietary fat is the macro-nutrient with the second highest thermic effect after protein. Fat is important for maintaining our hormonal levels and supporting our satiety after consuming a meal. Lastly, carbohydrates have the lowest thermic effect. The body digests carbohydrates faster than any other macro-nutrient. It does not mean that carbohydrates should be demonized. They are still essential for supporting your satiety hormone Leptin, your training performance, and your sleep. However, your carbohydrate calories should stress in complex or slow digesting carbs.
Food Quality and TEF
Certain foods give you a higher thermic effect than others and is more conducive for satiety on a fat loss program. You can eat foods you like and still lose weight on the condition that you’re adhering to a caloric deficit, but if you are not allocating most of those calories towards quality foods, you will have much more hunger issues on a diet plan. Healthy unprocessed foods have a higher TEF than processed junk foods. Healthy foods keep you fuller longer and cost your body more calories to digest. For example, 200 calories of oatmeal will have a higher TEF than 200 calories of a glazed doughnut. Oatmeal is a slow digesting carbohydrate food and contains more micro-nutrition in comparison to a glazed doughnut, which has been stripped of its nutrients through processing.
Conclusion
There are a few key take a ways from this article. First, majority of your total daily energy expenditure is going to come from your basal metabolic rate. These are the calories your body would be burning if you were to rest in bed all day. Second, the cumulative activity you do throughout the day will expend the second greatest number of calories in your body. Lastly, your body burns the least amount of energy by simply digesting food.
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