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Ever wonder how many calories you burn just doing day-to-day stuff? What about how many calories you use while sleeping? Did you know your brain uses a ton of calories just to watch Netflix?
That's your BMR - Base Metabolic Rate - and it's your biggest source of daily calories. But there are a few other ways to burn calories, too. They're all acronyms and initialisms like NEAT, EAT, and TEF. These are all the different ways your body uses energy. In fact, if we were to plot-out of all the calorie burning things in your life - we could come up with a mildly interesting looking chart.
These are your metabolic lines. Want to know what yours are?
Let's take a look.
Before we start drawing lines on a chalkboard like a middle school teacher - let's define the terms and understand all the data points.
First, your body is extremely complex. There are so many things happening at any given time that you're probably not aware of. All these bodily processes use energy - Calories - and you replenish those calories with the food you eat.
To make it complicated, it's not a simple [In - Out] equation. It's very complex with energy being stored in multiple storage tanks, and different body functions drawing from different fuel tanks. But for the purpose of this article, and fat loss in general, we can simplify it as an [In - Out] equation.
Eventually, fat loss programs boil down into [Calories in] versus [Calories out]. The [Calories OUT] part of the equation is all this article is about.
Here are the different parts of the Calories Out equation:
Base Metabolic Rate + Non-Exercise Activity-Induced Thermogenesis + Exercise-Induced Activity Thermogenesis + Thermic Effect of Food.
Try saying that five times fast.
Metabolism
Your metabolism is the biggest contributor to the [Calories Out] part of the equation. The word "Metabolism" is a catch-all word for all the physical processes your body uses to live and navigate your environment.
Your "metabolism" is composed of cellular processes, base metabolic processes, your daily activity, any extra exercise, and, ironically enough, the act of eating.
BMR
Base Metabolic Rate (BMR) is the term we use to explain the amount of energy your skin, tissues, brain, lungs, muscles, and other organs use just to exist. This number is never a zero. If you're alive, you're burning calories. Even if you're in a coma, your body still uses a base-level of calories to continue existing. It's not much, but it's more than you think.
For example, your brain uses between 200-400 calories per day.
Your lungs, heart, kidneys, skin, lungs, and other organs all contribute to a daily calorie expenditure. And the bigger you are, the more calories you burn just existing.
Even body fat cells require a certain amount of calories just to exist. For example, 50 pounds of fat mass (sitting in those love-handles, no doubt) require about 250 calories per day just to exist.
Of course your age, gender, and total body size all contribute to your metabolism. The older we get, the less calories we burn.
Men typically burn more calories than women, but that's only because of increased muscle mass if everyone is averaged together. If matched lean mass to mass, women burn pretty close to the same amount of calories as men. But in general, men burn more. Sorry ladies.
For example, a 6-foot tall, 28 year old male heavyweight powerlifter who weighs 300 pounds with an extra 50 pounds of fat will have a higher metabolism than a 5'5", 45 year old female office worker who hits the elliptical 2x per week.
As a personal trainer who works with married couples, it's not uncommon when the wife expresses her frustration that she can't eat the same as her husband.
NEAT!
In addition to your base metabolism, you also burn calories through daily activity. Even the activity you're not paying attention to. For example, when walking from your 2nd floor office to your car in the back of the lot, you're probably burning 20 calories. You likely burn a full one calorie every time you stand up from the couch.
It's not much, but it's honest work. And it adds up.
This is called Non-Exercise, Activity-Induced Thermogenesis (NEAT). It's every muscle contraction, step, lift, twist, and pull your body performs while navigating your environment.
This number is hard to quantify, but it can make up 20-30% of your daily calorie needs.
This is why calorie calculators often ask about your job. A school teacher, for example, will burn more NEAT calories than a sitting office worker. That's the nature of dealing with kids and standing all day.
This number can be very low, or astronomically high. A high NEAT can be a part of someone's daily life, and they're not even aware of it. For example, one of my clients (a younger guy who had difficulty putting on muscle mass), was expressing frustration that if he skipped a single meal, his body weight would drop significantly. He had trouble eating enough to counter his NEAT - because he was constantly moving. His job as an on-site manager and recreational landscaper kept him moving for almost 16 hours per day. He never sat still. Even sitting, he was always moving his legs and tapping his feet.
But this was his normal. So we factored in an extra 1000 calories per day of carbs and lean protein so he could gain muscle. It worked!
For anyone struggling with weight loss, that's a difficult thing to hear. Some people just move more and they don't even know it.
EAT
Here's the bad news: Your exercise doesn't burn as many calories as you think. In fact, even with an hour of exercise, you're probably not burning more than 500 calories. Most people don't exercise as hard as they think. In the grand scheme of things, unless you're exercising 7 days per week with an average of 2-3 hours per exercise session, it's almost best to NOT count exercise calories.
Many recreational exercisers workout for 3-7 hours per week. These are people who play a pick-up game of pickleball after work, or who hit the Peloton every day while watching the morning news. This leaves about 162ish hours per week where they're NOT exercising. In the grand scheme of things, it just doesn't add up.
Plus, the more you exercise, the less calories you burn while exercising.
It's not fair.
TEF
The last major contributing factor to daily caloric output is the Thermic Effect of Food - or the amount of energy it takes to break down and digest your food.
Yes, eating food causes you to burn calories.
But it's not much. It's about 10% of the food you eat. So estimate that if you eat 2000 calories per day, your body uses 200 calories to absorb and digest that food.
Finding Your Metabolic Lines
For all you number-nerds out there, this is where the fun begins. We can estimate all the numbers above and look at how many calories you burn on a daily basis.
The BMR is the most influential number, as it's the biggest. It's the minimum amount of calories we need, and the largest contributor of daily calories burned. It's our baseline. But as we go higher on the metabolic lines, they become less of a contributing factor.
Though it's important to note - these are just estimates. Estimates only go so far. More importantly, we tend to over-estimate the amount of daily activity and exercise we do. So don't get too attached to these numbers.
Calculate your BMR
There's a tried and true equation (several, actually) used to estimate base metabolic rate. It's slightly different for men and women.
MEN
BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years)
WOMEN
BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age in years)
If you don't want to crunch the numbers yourself, you can use this calculator.
This is your metabolic baseline. The minimum amount of calories your body needs to function. It contributes to about 65% of your daily caloric expenditures. If you eat less than this for a prolonged period of time, your metabolism may suffer. I call this number the metabolic "Blue Line."
Estimate Your NEAT
This part is very difficult to accurately measure. Not only do we over-estimate how active we really are, some days are simply different. If you're binge-watching Netflix on Sunday, but working on a construction site installing HVAC units on Tuesday, this number will be all over the place.
I would estimate, for most people, between 800-1500 calories per day of activity. If you're sick and in bed all day, this number might be lower. If you're a 240 pound mountain of muscle on your feet all day, it might be a little higher. Your NEAT contributes to about 20% of your total daily caloric expenditure.
I think of this as the metabolic "Orange Line."
Estimate Your EAT
The calories burned from exercise is up higher on the chart, and contributes significantly less than NEAT and BMR. If you don't actively exercise, this number is not a factor. If you exercise occasionally, this number is a low factor. Even hardcore exercisers will find it difficult to make this number a significant contributor to their daily caloric burn.
If you're using a heart rate monitor or smart watch to estimate these numbers, they could be way, way off. I write more about that here.
A very vigorous conditioning/lifting session lasting up to 60 minutes may burn as much as 200-300 calories. The average person burns 100 calories covering a distance of 1 mile on foot. A five mile run will burn about 500 calories - but remember - the more efficient you are at exercising, the less calories you burn doing it.
This is your metabolic "Grey Line." It makes up about 10% of your total caloric expenditure.
Estimate Your TEF
This number is the smallest of them all. It's at the top of the chart and contributes the last of the daily calories. It's 10% of your food intake. Like a nutrition tax.
This number can be useful in clinical settings, however for practical purposes we don't actually count this number. If you're tracking your food, and eating 2000 calories per day, it's 2000 calories. Not 1800. It makes up about 5% or less of your total caloric expenditure.
But I'll include this on the chart as the metabolic "Yellow Line."
When you put all these numbers together, your chart looks like this:
You can see how, even with exercise, your base metabolism and daily living make up the majority of your daily caloric burn.
Know Your Numbers
Knowing these numbers - and what they mean - can take some of the mystery out of the fat loss game. It can also explain why some people can eat "whatever they want" and get away with it.
Basically the bigger, more muscular, and more active you are, the more flexibility you have in your dietary budget.
But with this knowledge comes an understanding that they're just estimates. Don't spend too much brain power on calculating your exact numbers.
Although if you did, your brain would probably burn like, 10 extra calories.
MORE Information
Estimate your daily caloric needs with my calculator.
Some scientific research showing how many calories the organs burn.
Calculate your BMR with this calculator.
Know your limitations - calorie trackers are often wrong!
Are you eating too little? Get a free consultation with me and find out.
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