How to Calculate Your Macros Part 1 – Calculating Calories

Portion by Bradley P Johnson

Now that you know what macros are you might be asking how to figure out exactly how many of them you need every day in order to attain your fitness goals. The beginner’s guide gave some general guidelines, but here we’ll get a little deeper into it.

The first thing we need to figure out in order to determine where your macros should be is exactly how many calories you need to be getting on average to meet your goals. (I’m assuming you know your goal, e.g. lose fat, gain muscle etc., so if you don’t make that step one and figure it out first.)

Why calories first? When it comes to losing weight (i.e., fat) or gaining weight (i.e., muscle) the single most important factor is your calorie intake.

Calories Are King

There are easily a thousand different diet models all claiming to have the one magic secret to helping you lose weight. Most of them focus on eliminating this or that or playing with meal timing or fasting for so long or some other thing – but the fact remains that when it comes to the foundation of gaining or losing weight calories are really all that matters.

Whether you’re eating 100% ‘clean’ or nothing but Twinkies and junk food if you’re genuinely taking in more energy than you use you will gain weight and if you’re using more than you take in you’ll lose it.

Now before the ‘A calorie is not a calorie’ crowd get their torches lit and pitchforks distributed I should note, what that weight is – muscle, fat, etc. – can be determined by where those calories are coming from. That’s a question of what color to paint the house though and we’re still talking foundations here. We’ll get to where the calories should come from and when you should get them later, first we need to know how many you need.

Calculating Your Current Calories

There are a handful of ways to go about this ranging from more to less complicated and more to less accurate. All of these are trying to determine your Basal Metabolic Rate (BMR) which are your ‘coma calories’, the amount of energy your body would burn if you did nothing but lay there in bed all day and not move. It’s essentially the bare minimum amount of energy your body needs to keep running without any added activity.

The most complicated, though arguably most accurate, is RQ testing through a system like what eNewLeaf offers. Technically speaking their resting metabolic testing should be extremely accurate compared to the other calculation options I’ll give. I’ve used them in the past and was happy with the results.

That being said, I think it’s a lot easier to have a less accurate initial estimate and then adjust up or down from their based on your rate of progress. Testing like what eNewLeaf provides can be expensive and considering your values will change over time would require repeat visits.

The one potential benefit this type of testing offers other than providing more accurate initial values is that it can also tell you which energy systems your body prefers using. In basic terms how efficient your body is at actually burning fat.

It can be an interesting thing to know, but I don’t find it terribly useful and it won’t change our macro calculations so I wouldn’t bother unless you really want to know this stuff.

My preferred method personally is the Katch-McArdle formula. This is still a best guess situation but it tends to get pretty close and then you can adjust from there after a few weeks once you see how things are going. There are just too many individual variables for this to get an accurate value for everyone but I’ve found it’s the best combination of accuracy and convenience.

The Katch-McArdle Formula: BMR = 370 + (9.8 x lean mass in pounds)

If you’re more metric minded change that 9.8 to 21.6 and pounds to kilograms.

Your lean mass is the weight of your body minus the weight of all of your fat. To figure this out you’re going to need to determine your body fat percentage – there are a lot of ways to do this ranging from pinch tests to bio-electric impedance to complicated things like hydrostatic weighing. Most of the nicer bathroom scales will do it for you (I particularly like the Aria) and if you belong to a gym any one of the trainers should be able to give you a pretty good estimate.

Once you have your body fat percentage subtract that amount from your total weight to get your lean mass. So a 200 lb. person at 20% body fat would mean they have 40 lbs. of fat on them (200 x .20) and 160 lbs. of lean mass (200 – 40).

If you have no idea whatsoever about what your body fat percentage might be and no good way to find out you can use the revised Harris-Benedict equation instead. This one differs between men and women.

Men’s Harris-Benedict Formula: BMR = 88.362 + (6.251 x weight in lbs.) + (12.189 x height in inches) – (5.677 x age in years)

Women’s Harris-Benedict Formula: BMR = 447.593 + (4.203 x weight in lbs.) + (7.869 x height in inches) – (4.330 x age in years)

And in metric:

Men’s Harris-Benedict Formula: BMR = 88.362 + (13.397 x weight in kg.) + (4.799 x height in cm) – (5.677 x age in years)

Women’s Harris-Benedict Formula: BMR = 447.593 + (9.247 x weight in kg.) + (3.098 x height in cm.) – (4.330 x age in years)

These are going to potentially be a little less accurate, but they’ll do well enough for the moment.

Once you have your BMR you’re going to want to adjust it a touch to account for your daily activities to get your Total Daily Energy Expenditure (TDEE). In my experience most people vastly overestimate their daily activity levels. For that reason I usually recommend a x1.2 multiplier for most people. This usually winds up being a bit of an underestimation but works if you’ve got a desk job. If you’re on your feet most of the day (waiting tables, working on machinery, etc.) then you may be better off with a x1.4 multiplier. If you’re in a genuinely strenuous line of work (roofing, construction, etc.) then you can bump it up to a x1.6 multiplier.

Don’t try to factor exercise in here, just your day to day activities. In other words if you have a desk job but workout 5x per week you should still start with x1.2 as your multiplier.

So our 200 lb. 20% bodyfat example from before would use Katch-McArdle to get a BMR of 1,938 kcal. (370 + (9.8 x 140 lbs.) = 1938) and then, since he’s got a desk job, would add in the multiplier to get to a TDEE of 2,325 kcal. (1938 x 1.2 = 2325.6). Always round down to the nearest 5 or 0 for simplicity’s sake. These are estimates remember and will need adjusting over time anyway.

Now that we’ve got our TDEE – the estimated number of calories we need to take in to remain exactly the same weight – we need to figure out how to manipulate those numbers to reach our goal.

Calculating Your Target Calories

We don’t want to just stay the same, so you’re going to need to either take in fewer calories if you’re trying to lose weight or more calories if you’re tying to gain weight. I’m going to use the general Leangains terminology and call them a Cut and a Slow Bulk respectively.

Since most of the people I coach are looking to lose weight, we’ll start with the cut.

Calories for a Cut

Since we’re looking to lose weight while cutting that means that you’re going to need to adjust your calories down from your TDEE. How much you’re going to adjust down is going to be based on how much weight you want to / can safely lose per week.

People who have more to lose, i.e. people with a higher initial body fay percentage, can generally safely lose more weight per week while people who are closer to their goal and have a lower body fat percentage will be on the lower end of the spectrum. Here are some general guidelines for what you should be able to expect safely.

  • 30% Body Fat or Higher – 2.5 to 3 lbs. per week

  • 20 – 29% Body Fat – 2 to 2.5 lbs. per week

  • 15 – 19% Body Fat – 1.5 to 2 lbs. per week

  • 12 – 14% Body Fat – 1 to 1.5 lbs. per week

  • 10 – 11% Body Fat – .5 to 1 lb. per week

Find yourself on the chart and then figure out from there how many pounds of loss per week you want to aim for. These are basic guidelines based on a combination of outside data and my own experience with clients. Note that you can always aim for a slower cut than what’s listed under your body fat percentage but don’t try to do more. If you’re 30% body fat there’s nothing wrong with aiming for a nice slow 1 pound per week, just don’t shoot for losing 3 pounds per week if you’re only 12% body fat or you’re likely to run into problems.

Once you’ve determined how many pounds of loss to shoot for we need to translate that into calories. The general rule is that it takes 3,500 calories to create a 1 pound change in weight. I say general because it’s not technically an exact science but it gets the job done.

So our previous 200 lb. 20% body fat example would look at the chart and decide he wants to shoot for 2 pounds of weight loss per week. That means he needs to put himself in a caloric deficit of 7,000 calories (3500 kcal x 2 lbs. = 7,000 kcal) per week.

If you’re a little on the short side, I would recommend aiming a little on the lower side. It doesn’t always make a big difference but it does help sometimes.

Always aim to make your weekly caloric deficit a product of diet alone and not training. There are a handful of reasons for this. First of all, there’s a high variance in calorie burn for the same activity from person to person. While the bomb calorimetry isn’t perfect either it’s more accurate than estimates of what you’re burning during an activity. Second adding in a ton of extraneous training just to burn more calories is going to add substantially more stress to your body than just reducing intake and we don’t want too much stress. Lastly, your training should be focused on its own goal not on burning up extra energy because you ate too much.

The most basic way to achieve that weekly deficit is to divide your total weekly deficit need by 7 and then subtract that amount from each day’s intake. So for our example person he would want to cut 1,000 calories each day from his TDEE to eat 1,325 kcal daily (2,325 kcal TDEE – (7,000 kcal / 7 days) = 1,325 kcal).

Personally, this sounds a bit aggressive and our example gentleman may find 1,325 is a bit low for comfort. In that case he could bump up to a slower but more comfortable 1 pound loss per week at 1,825 kcal per day. Usually if your target dips too far below your BMR you might find it’s kind of miserable and unsustainable. It’s all about finding what works best.

I’m also a fan of Leangains-style calorie/macro fluctuations which would involve higher calories on training days and lower or rest days rather than a flat deficit each day. Regardless of how you do it, the important thing is that your weekly calories add up to the specified deficit.

Calories for a Slow Bulk

So what if you want to gain weight rather than lose weight? You essentially follow the same process in reverse.

Here the calories are going to be determined more by your training level than by your body fat percentage or body composition. I like to break it down along Alan Aragon’s lines of Beginner, Intermediate, and Advanced trainee.

Here’s how to figure out where you are based on three main lifts.

  • Beginner – Anything below Intermediate, usually less than 2 years of training.

  • Intermediate – Bench Press: 1.2 x body weight, Squat: 1.6 x body weight, Deadlift: 2 x body weight, usually between 2 to 5 years of training.

  • Advanced – Bench Press: 1.5 x body weight, Squat: 2 x body weight, Deadlift: 2.5 x body weight, usually 5 years or more of training.

If you’re in the Beginner level you can expect between 2 to 3 lbs. of muscle gain per month and should shoot for a surplus of around 200 to 300 kcal per day to start.

If you’re in the Intermediate level you can expect between 1 to 2 lbs. of muscle gain per month and should shoot for a slightly lower surplus of 100 to 200 kcal per day to start.

Lastly if you’re in the Advanced category you should expect only about .5 lbs of muscle growth per month and should aim for a small surplus, somewhere at or below 100 kcal per day to get started. Advanced trainees will find it’s much easier to track strength gains and other metrics than it is scale weight since at this level increases in pounds will be smaller and harder to notice.

So our example person at 200 lbs. and 20% body fat wants to go on a slow bulk and add some muscle. He’s an absolute beginner at weight training, so he can expect to put on at least a few pounds per month and needs to shoot for a surplus of 200 to 300 kcal per day. If he goes right in the middle that puts him at a target of 2,575 kcal per day (2325 kcal TDEE + 250 kcal = 2575 kcal per day).

Adjusting your Calories

Your daily calorie needs are going to change.

Even outside of training and the weight change involved with adjustment of caloric intake there are so many other factors involving your metabolism and Non-Exercise Activity Thermogenesis (NEAT) that there’s no way you’ll keep them consistent for long.

As such, you’re going to have to adjust your calorie intake up and down as you go based on what your goals are and how much progress (or lack thereof) you’re seeing in either direction.

You don’t want to make too drastic of changes too soon, so I would always stick with what you’re doing for at least two solid weeks before making adjustments – preferably three or four. Solid weeks here means hitting your calorie targets every single day.

If, after three or four weeks consistently hitting your targets on a cut you find that you’re not losing as quickly as you’d like or not at all then adjust your calories down by between 5 and 10% and see how that affects things. If you’re losing too quickly adjust up by 5 to 10% – losing too quickly or more than is indicated on that chart above likely means you’re also losing muscle which is a bad thing.

If you’re on a slow bulk and find yourself not making any progress after hitting your targets for three to four weeks then increase your daily calorie intake by between 3 and 6%. If weight is gained too quickly for where you are on the training levels above you’re likely putting on fat in addition to muscle and should decrease your daily calories by 3 to 6% instead.

Keep in mind that, particularly if you’re new to training or making large changes to your macro percentages (particularly carbohydrates) you may have some drastic fluctuations in water weight in that first week. Stick it out and give it time before you make any substantial adjustments.

This is the first step in figuring out your macros. We’ll get into how to actually structure your macro percentages in the next article, but this will be the foundation those are built upon.

If you’re feeling uncomplicated, you can just use these values to lose or gain weight. While there are potential benefits to getting more involved and complicated with things it’s not necessary, so if you just want things to be easy set your calorie targets based on everything above and stick to them without worrying about specifically what it is you’re eating.

Have any questions about setting your calorie goals up or any suggestions or personal experiences you’d like to add? Leave a comment!

Photo Credit: Bradley P. Johnson

Adam is a former English teacher turned personal trainer and writer. He’s addicted to learning, parkour and martial arts. In addition to being a voracious bibliophile Adam’s fascinated by anything related to health, fitness and language. When not studying or training he can usually be found curled up with a good piece of fiction. You can e-mail Adam at Adam@RoadtoEpic.com