How To Calculate Your Calorie Needs

Why should you learn how to calculate your calorie needs?

If you don’t mind me driving up the word count to tell you, then I’ll explain!¹If you just want to get to the fun math part of figuring out your calories, then scroll down and save yourself the headache of becoming more knowledgeable. Yeah, knowledge. FUCK THAT SHIT!

*ahem*

As you know, food contains calories, the units of energy used by the body to survive and function. Well, while everybody’s body needs calories, not everybody has the same energy needs. This is owed to the fact that we’re all special. Yup, everybody’s body is different.²See what I’ve been doing with “every body” and “everybody”? Yes, this is writing at a level reached by few! Specifically, daily calorie requirements are a function of height, weight, age, activity level, and overall health, all of which are unique to each person. It’s for this reason that a 6’4” 20-something year old Michael Phelps could consume 12,000 calories per day at the height of his swimming prowess but 5’3” 45-year-old Susan in HR who sits behind a desk all day reviewing the stream of sexual harassment complaints against you can get by with significantly less.³Phelps revealed years later that the 12,000 calories was a myth. In actuality, he was only eating a paltry 8,000 to 10,000 calories per day. Jesus, the U.S. can’t afford to feed its athletes?!?!

With all of that said, exactly how many calories do you need?

What a truly splendid question!

The recommendations vary from organization to organization. For instance, the United States Department of Agriculture suggests that the average man needs 2,700 calories and the average woman around 1,800. Compare that to the blanket recommendation given by the United Nations Food and Agriculture Organization, which is that the average adult should consume no less than 1,800 daily calories. So that’s around how much you should eat. I mean, if you want to be average.

But you’re not striving to be average, right? Because the pursuit of that is not why you’re reading this when you could be doing much more exciting things with that action-packed life of yours, those recommendations just won’t do. Nope, average just doesn’t go along with an extraordinary person such as yourself!

Being the case that you don’t want to be “average”, which is why you weight train and want to transform your body so you don’t look like the rest of these schlubs, you have to calculate your calorie needs to find out the appropriate intake specific to you.

And how you do that is via a three-step process that involves

That now out of the way, let’s get to the fun stuff and figure out your calorie needs!⁴It’d help tremendously if you had a calculator, abacus, Napier’s bones, or some other counting apparatus as you followed along. But please, if you can do the computations in your head, then by all means go ahead, smarty pants!

On the off chance that you don’t want to do the calculations by hand, you can do yourself the service of using my daily calorie needs calculator to do the math for you.

BASAL METABOLIC RATE

The first step involves finding out how many calories you burn at complete rest. That means how much energy your body requires to perform all of the processes necessary for its survival were you finally beaten into a coma for your habitual line-stepping. This is better known as the basal metabolic rate (BMR).

There are many formulas available for figuring out BMR. The most accurate are formulas like the Cunningham or Katch-McArdle formulas, which take body fat percentage into account.

Oh, but you’re not getting DEXA scans? Or doing hydrostatic weighing by dunking your entire body underwater?! Or using air-displacement plethysmography?!?!

Instead, all you have are calipers and bioelectric impedance monitors, both of which have wide margins of error?

Seeing that you don’t know or can’t accurately measure your lean body mass, we’ll play it safe here and calculate BMR with what’s known as the Mifflin-St Jeor equation.⁵Just so you know, the original and revised Harris-Benedict equations are also available to you if you don’t know your body fat levels. While the Harris-Benedict equation is more widely used, the Mifflin-St Jeor equation is slightly more accurate and is what I’m using for illustrative purposes.

EXAMPLE: MALE
25 years old, 6’0″, 200 lbs
BMR = (4.536 × 200) + (15.88 × 72) – (5 × 25) + 5
BMR = 1931 calories

EXAMPLE: FEMALE
27 years old, 5’5″, 164 lbs
BMR = (4.536 × 164) + (15.88 × 65) – (5 × 27) – 161
BMR = 1480 calories

ACTIVITY LEVEL

Remember, BMR is how much energy, or calories, you need to do NOTHING. In other words, were you in a coma after someone finally pummeled you for stepping over the line, your feeding tube would have the equivalent of your BMR in it.

But alas, no one has made you comatose for all the times you’ve habitually stepped over the line…at least not yet. So because you’re conscious and every little thing you do requires energy, we now have to factor your total daily energy expenditure (TDEE).⁶TDEE is science talk for how many calories we burn by moving around and doing stuff.

To find your TDEE, all you have to do is locate your activity range and then multiply your BMR by the listed multiplier.

EXAMPLE: MALE
Let’s suppose our 200 lbs male with a BMR of 1931 calories per day is a teacher who provides educational instruction to your knucklehead children — or at least tries to. Let’s suppose that he dusts off his gym membership card once a week with the hope that it’ll even out the excessive drinking he does every weekend to help ease his pain of knowing from firsthand experience that the future of this country is doomed.

TDEE = BMR × Activity Multiplier
TDEE = 1931 × 1.38
TDEE = 2665 calories

EXAMPLE: FEMALE
Let’s suppose our 164 lbs female with a BMR of 1480 calories per day stands on her feet all day as a saleswoman in a department store. After eight hours in retail hell, she does a weight training session at night. Oh yeah, let’s not forget her fasted cardio session in the morning, with her doing two-a-day workouts in preparation for an upcoming show.

TDEE = BMR × Activity Multiplier
TDEE = 1480 × 1.90
TDEE = 2812 calories

NOTE: Like finding BMR, there are different methods of arriving at TDEE. Some use different activity multipliers. Some break the activity levels into 3, 4, 5, or 6 categories. Some assign different designations to the activity levels. Some provide varying definitions of what the categories themselves mean. Don’t fret. Your calculations may come up different from one method to another, but if trying to lose fat, for example, the variance won’t be enough to be the difference between that happening and you getting fatter.

ADJUSTING FOR GOAL

TDEE calories reflect the amount of calories that the body requires to maintain its body weight. Not everyone wants to remain the same weight, though. Some want to lose fat and slim down. Some want to gain mass and become bigger. This is where we adjust for that depending on our fitness goal.

Since man stepped out of the primordial goo, the advice that’s been passed down from generation to generation has been to add or subtract 500 calories from maintenance level. We’re not going to do that here. Instead, we’re going to use percentages because we fancy, baby!

For some, a small adjustment of calories 10-15 percent above or below maintenance is ideal.

Who’s it ideal for?

A small adjustment can create a small deficit, which is ideal for already lean individuals trying to get leaner. See, it gets harder and harder to lose body fat as you get leaner, with the body preferring to burn muscle for fuel than tap into its fat stores. A small deficit works in preserving as much muscle as possible. Those trying to put on muscle who are mindful of limiting the amount of fat they put on would favor a small surplus.

For others, a large, more aggressive deficit or surplus that’s +25 percent above or below maintenance works for them. This large of a deficit is primarily reserved for the obese and those close to it. This large of a surplus is advised for so-called “hardgainers” who can’t put on weight no matter how hard they try because their metabolism is so fast that the laboratory-created child of the Flash, Quicksilver, and Sonic the Hedgehog is running in slow-mo compared to their superhuman metabolic rate. For the greater population, however, a +25 percent change in calories is too large of a gulf or jump to start with, which can result in them losing muscle if their goal is shedding fat or gaining chub if their goal is putting on quality size.

Depending on your circumstances, your best bet is to create a caloric surplus for muscle gain or caloric deficit for fat loss by adjusting your TDEE by 20-25 percent. This moderate approach works well enough for the majority of folks.

EXAMPLE: MALE
Let’s suppose our 200 lbs teacher with a TDEE of 2665 calories wanted to increase it by 20 percent. Why?! To bulk up and stop having his pupils run his pockets for extra lunch money, of course! That’s why!!!

Daily Calories = (TDEE × surplus) + TDEE
Daily Calories = (2665 × 0.2) + 2665
Daily Calories = 3198

EXAMPLE: FEMALE
Let’s suppose our 164 lbs saleswoman with a TDEE of 2812 calories wanted to decrease it by 20 percent. Why? To lose the excess fat necessary for her to step on stage, do a quarter turn, arch her back, and pop her booty out far enough for all in attendance to also see her vajayjay in all its splendid glory. That’s why!!!

Daily Calories = (TDEE × deficit) + TDEE
Daily Calories = (2812 × 0.2) – 2812
Daily Calories = -2250⁷See that negative sign? Don’t get spooked by it. Remember that our 164 lbs female is in a caloric deficit, thus the negative calories. In actuality, because…ummmm…it’s not possible to eat negative calories, her true daily caloric total is 2250.

OTHER ADJUSTMENTS:

Be aware that the amount of calories to eat is just an estimation of your energy needs, not a hard and fast number. No formula can figure out your caloric needs right on the dot and with 100 percent certainty.

Rather than overreact and do something drastic like scrap your diet because you think it isn’t working, you should ride it out. If the instrument you’re gauging progress with — e.g. scale, measuring tape, calipers, mirror, etc. — isn’t reflective of change after the first three weeks, then lower or bump your calories by no more than 10 percent and give the change another 2-3 weeks to take effect. The same recommendation goes for if you find yourself spilling over or losing muscle at more than 2-3 lbs per week. Just modify your calories anywhere short of 10 percent and allow time to see what happens.

Capiche?

Additionally, you should recalculate total caloric intake every time there’s a 10-15 lbs loss or gain. Yes, that means redoing BMR, multiplying it by an activity multiplier, and increasing or decreasing the TDEE by however much to find your new total daily requirements.

Yes, do all that over again!⁸I know, having to do all that intensive labor again is a bummer! Given the prospect of that, you now understand the argument for slavery and, as much as you pretend to be progressive in your thinking, you could be easily compelled to champion its return.

Wait, did you just calculate your calorie needs?

Wasn’t it as fun as I told you it’d be?!

But noooooooooooooooooooooooooo, you didn’t want to believe me!

Sure, you didn’t show the greatest of ease with the addition. Or subtraction. Or multiplication. And fuck, the order of operations presented quite a challenge.

Wait, you know what?

This shit wasn’t as much fun as I made it out to be.

Yeah, this was real rocket science shit!⁹If you’re in the mood for more excitement in your life, then take the information you’ve found out here and use it to figure out your macros!

Now, not only should you be mad that I lied about the entertainment value but it’s probably going to piss you off to no end that I also provided a link to the web page that has a calculator that’ll do the math for you. See, this is exactly why you should read the footnotes, folks!¹⁰The link was given in the third footnote.

Glossary: bulk, calories, cardio, diet, exercise, fitness, goal, gym-goer, metabolism, muscle, weekend, workout

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Monster Longe

Monster Longe is a personal trainer in San Diego. He has been lifting weights for +25 years and training clients in the gym and online for about half of that time. When not working with clients or making content that's easy to read, understand, and apply to everyday life, he enjoys long walks and leaving buildings crushed and entire city blocks decimated in his wake.

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