A Primer on TDEE
This article is 1511 Words and takes 8-10 minutes to read
🎧 Listen to the audio version aboveHow much does my body burn on a daily basis?
Aside from exercise, where are these calories going?
How do the foods I eat and the exercise I do affect my energy needs?
These are all great questions that you are probably not asking yourself, but since you are here…let’s dive in.
Last week I posted an article about the benefits of walking for overall health, you can find this article here.
In the article, I discussed the impact of walking on daily energy expenditure. As a follow-up, I think it would be useful to break down the different components of Total Daily Energy Expenditure (TDEE).
*Note: moving forward, I’ll be using, energy, fuel, and calories interchangeably.
The TDEE equation :
TDEE is the total amount of energy your body will burn throughout the day, here is how you calculate it: TDEE = BMR + NEAT + EA + TEF
BMR = Basal Metabolic Rate
EA = Exercise Activity
NEAT = Non-Exercise Activity Thermogenesis
TEF = Thermic Effect of Food
These four categories account for all the energy you expend in a day. The percentage will vary based on a few things, such as your activity level. As an example, if you are very active, EA will be a larger percentage of the total and BMR will account for a smaller percentage. Not necessarily because it requires fewer calories but because as a whole you are burning more, therefore the relative contribution is smaller.
Let’s look at these four categories in more detail. I’ve also added relevant information about each to make this more practical. Nerding out on this stuff is cool for coaches like me, but it can help you have a better understating of some of the stuff you hear online, clear up a few misconceptions or give you a fresh perspective on how your body uses energy.
Putting things into context: In an ideal world, all the energy you burn in a day will be compensated by the foods that you eat. This would allow you to maintain what is called energy balance. More activity increases what you need to consume in a day. On the flip side, if you want to lose weight, you would need to create an energy deficit by eating fewer calories than you burn.
🧠 Basal Metabolic Rate (BMR):
BMR accounts for 50-75% of your TDEE. This is the energy your body requires to keep your basic metabolic function online. You could say it’s the energy you need to keep the lights on. It’s very important to note that this is our biggest demand for energy, and it is also a big part of what you could call your metabolism. So if I wake up tomorrow and decide I don’t want to get out of bed, I don’t move or blink or do anything else until I fall back asleep that night, my body would still burn over 50% of my typical day going out and about.
Here are a few facts about BMR:
Muscle & metabolism: Building, maintaining and using muscles is a somewhat costly process, this is why people say that resistance training can “boost metabolism”.
Fitness Trackers: When it comes to estimating total energy expenditure, your watch or fitness tracker are considered precise, but not accurate. This means that they do a good job at telling you if today’s workout burned more calories than yesterday’s, but they are not great at telling you if that amount is actually representative of what you actually burned.
Here is an example: if your watch tells you that you burned 500 calories in training yesterday and 600 today, you can be sure that you burned more today. But those numbers could be 400 and 500 or 600 and 700. Research shows that, depending on the devices, it can have an error rate of over 50%. Doesn’t mean that the info is useless, but you have to take it with a grain of salt.
Energy compensation: This is pretty crazy: exercise has been shown to decrease energy expenditure for the rest of the day. This will vary based on the person and the context, but can have an impact as large as 30%. If you think about it from an evolutionary perspective, it’s probably because your body wants to offset some of the energy you just burned as a way to prevent you from running out of fuel…so exercise burns calories, but your body dials back its expenditure in response. There is a diminishing effect here, the more you exercise the least your body adjusts in response, and it’s hard to say what the net effect actually was on a given day 🤯 (by the way your watch definitely can’t tell you)
👟 Exercise activity (EA):
Exercise activity accounts for 0-30% of TDEE, it’s the amount of energy you expend during your training session.
Here are a few facts about EA:
What burns more calories, does it matter? Longer, less intense exercise will burn more calories during exercise. Shorter, more intense exercise will burn less during the activity but will burn more after you are done training, this is called excess post-exercise oxygen consumption (EPOC). Which one has a bigger impact will depend on the total amount of work (the time x the intensity) you did. In any case, burning calories shouldn’t be the main reason you work out. Being fit, healthy and functional should be the main reason.
Fat burning or carb burning: Based on the rate of work you are doing (the intensity) your body will use predominantly more carbs or more fat to create energy. Lower intensities typically shift you towards using more fat, and higher intensities need to use carbs to be able to create energy at a fast enough rate for you to keep up. But it’s important to understand that using fat for fuel and burning body fat are two very different things. The only thing that affects how much body fat you are losing is not the intensity of exercise, but if you are in a calorie deficit or not.
🚶 Non-Exercise Activity Thermogenesis (NEAT):
Like exercise activity, NEAT is the energy you use to perform all daily activities above BMR that is not yet considered exercise. Getting around, carrying the groceries, gardening, your hand gestures, etc. Another component is spontaneous movement like fidgeting, which can vary a bunch between individuals and based on other factors like how much energy you have coming in. NEAT can vary by hundreds of calories based on your work and lifestyle, even up in the thousands of calories in some extreme cases. Which can have a big impact on how many calories you burn in a day.
Here are a few facts about NEAT:
Eat less…burn less? People who are in significant calorie deficits can have involuntary reductions in NEAT, maybe they will subconsciously make the decision to walk less, stand less or fidget less as we said above. This can have an impact on the amount you expend in a day. On the other hand, some people tend to ramp up NEAT involuntarily if they eat more, thus burning off some of the excess calories, making it harder to gain weight. There seems to be a big genetic component to this.
How much can NEAT account for? People with a very active lifestyle and/or an active job can burn beyond a thousand calories a day in the most extreme cases, so this can have a pretty big impact on the total daily amount. In other words, being active beyond your workout can be huge for energy expenditure.
🧆Thermic Effect of Food (TEF):
Thermic effect of food accounts for 5-10% of TDEE. It’s the energy your body requires to process the food you eat, different foods require more energy to get assimilated than others.
Here is what you need to know about TEF:
Protein burns the most: Protein requires WAY more energy to assimilate than other macronutrients. Which is one of the big reasons that most nutrition experts recommend higher protein intakes to their clients.
Processed foods burn less: The opposite can be said about processed foods, calories from processed foods are much less expensive to assimilate, so if I eat 500 calories from whole foods versus 500 calories from processed foods the net amount that gets into my body will be more for processed foods.
💨 TL;DR:
Here’s our physiology lesson for the day. In my opinion, every avid exerciser should understand these concepts, hopefully you learned a thing or two. I’ll leave you with a quick recap:
On any given day, the majority of your energy demand comes from your body’s basic function
Moving around can also account for a lot of calories, often more than your workout itself. But your body tends to compensate in different ways to try to counteract all this movement. The amount by which it does this is hard to measure
The process of eating, digesting food and using its content for different purposes in our body also cost energy, the type of foods you eat can be more or less expensive to assimilate
See you soon for the next lesson ✌️
PS: I you enjoyed the article or if you have any questions, feel free to reach out. Similarly consider sharing it with someone who would find it interesting!
