Understanding Your Total Daily Energy Expenditure (TDEE): Beyond the Basics

Jul 30, 2024

The question popped up and I decided to answer in a post :)

#EnergyExpenditure #TDEE #HealthyHabits #WeightManagement #WellEverEats

So, how much energy does a body actually spend throughout the day?

Our Total Daily Energy Expenditure (aka TDEE) consists of four components.

Our Basal Metabolism [Rate] (BMR) - how much energy we need to maintain bodily functions, such as breathing, blood circulation, replenishment of the dead cells, brain function etc. This is the amount of energy we spend while resting.
If we eat something our body spends energy to digest the food. This is known as TEF (Thermal Effect of Food) and accounts for about 10% of our daily energy needs.
Another component, accounting for approximately 15% of our daily energy needs, is NEAT (Non-Exercise Activity Thermogenesis) - the energy we spend on activities of daily living, including walking, cooking, cleaning, maintaining posture, fidgeting and so on. This component may vary significantly from person to person and depends on many factors.
Lastly, another portion of TDEE is planned exercise activity and the energy we spend on it. In most people it is THE SMALLEST contributor to your energy expenditure (about 5%).

For example, an average female with BMR around 1450 kcal (calculated using a special formula) will spend about 140 extra Calories per day to digest food (TEF) and another 220 kcal on daily activities (NEAT) if she is sedentary.

TDEE = 1450+140+220=1810kcal - the energy she will need every day to support a completely sedentary lifestyle and maintain her weight.

If our lady adds some planned exercise in her schedule, let’s say, she lifts weights twice a week (it’s about 300 kcal per hour) and walks for 30 minutes three times a week (about 200 kcal each walk) it will add 1200 kcal per week of Exercise Activity Thermogenesis (EAT) or about 170 kcal per day.

TDEE = 1450(BMR) + 140(TEF) + 220(NEAT) + 170(EAT) = 1980 kcal

Here’s what happens if our lady decides to hop on a diet and reduce her food intake.

EAT stays the same in case she sticks to her training plan.
TEF may slightly decrease, because she needs to digest less food. But it’s not guaranteed (lower-calorie foods are often harder to digest and use more energy). So, most likely, the effect here will be insignificant.
BMR depends on body weight and decreases with weight loss. However, the more muscle mass she loses the more it affects the BMR, because muscles are metabolic tissue on their own. Also if she eats less food than her BMR, her body may begin to slow down its basic processes to conserve energy and prevent starvation.

That’s why it’s critical TO NEVER EAT BELOW YOUR BMR for extended periods of time. Your body will borrow energy from itself to maintain the most critical functions.

NEAT is what typically is affected the most when we begin to eat less. She may begin to unconsciously preserve energy: sit more, lean onto wall instead of standing, avoid going somewhere or moving at all if not absolutely necessary. It’s how her body signals that food is becoming less available (yes, we are still running the same brain as our hunter-gatherer ancestors) and she needs to get extra careful with her “spending patterns”.

So if you decide to begin limiting your energy intake for weight loss purposes, keep in mind the following recommendations:

Learn your BMR and always provide your body with enough food to not worry about survival. Avoid consuming less than your BMR for extended periods (one random day every once in a while isn’t gonna kill you, but it should not become a habit).
Cut calories gradually. It is recommended to create caloric deficit around 10% of your TDEE for the most comfortable, sustainable and safe weight loss.

Remember that there is no finish line you have to cross, think about your life AFTER weight loss. What do you want it to be? What habits would you like to build so that future you is healthy and happy in her body? Does it matter if you hit your weight goals in a year or in three, but with less effort put into it and less effort needed to maintain the results?

Our bodies are amazing. They can do incredible things. Let’s pay them with love and respect and some good food ;)