How to Calculate Your Macros

Anyone whose ever been on a diet has had to deal with the dreaded calorie, and once you really get into the details, now comes the macro. If you’re just starting out, you may be wondering… “What the heck is a calorie and what are the macros?”. Well, I’m going to break it down for you, in little edible bites.

Let’s start with the basics.

What is a Calorie?

Most everything you eat or drink contains calories.  To keep it simple and avoid getting to technical, calories are an energy source your body uses to function. Whether it’s digesting your last meal or giving you the strength to move a couch, calories are being burned. You brain is the number one use of calories in your body.

So now that we know what a calorie is, we have to figure out how many to eat. This can be a cause of anxiety for some, or more typically, it can just be a pain in the butt. If you want to lose weight, you are going to need to restrict calories. 

Determine Your Maintenance Calories
Maintenance calories are the amount of calories that you need to stay at a consistent weight where you neither gain nor lose any weight. Keep in mind that natural daily fluctuations (like water weight, hormones, bowel movements, etc) can be up to 5 pounds.

Here are a couple of ways to get the numbers that we will go over:
  1. Use an activity tracker, preferably with a heart rate sensor. I use the Fitbit Versa, but you can find many different kinds on amazon. Try to find one that suits your needs and looks. Check out the links below if you want to pick one up, or upgrade your current one.
  2. Do the Math… dreaded and despised, but can also help you get a baseline of your needs
  3. You can also use a guesstimate. This is typically a good starting place for most.

Option 1: Using an Activity Tracker

If you use an activity tracker such as Apple Watch you can use your total calories burned as your starting point. The total calories burned can be found in the Activity app under the calories section. Hint: You need to swipe right to see them.

If you use Fitbit, you can log onto the desktop dashboard and see your average calories burned for the past 7 or 28 days. Choose a time frame where you have not been restricting your calories, but you have not been gaining weight.

If you do not have any data for a time when you have been maintaining your weight without restriction/binging then try using options 2 or 3.

Option 2: The Commonly Used Guesstimate

This is probably the easiest way for you to get your maintenance calories if you are forever on a diet, or if you don't like math. I prefer this method because I am only looking for an estimate. None of the methods are going to be as accurate as spending all day everyday in a lab. The best that we can hope for, outside of being lab rat, is to get a starting point and use trial and error to adjust.

To guesstimate your calories, you can use the simple equation:

Body weight X 10-15

Use 10-12 if you are trying to lose weight

Use 13-15 if you are trying to maintain your weight

Once you have your number, stick with eating this many calories for at least 2 week before you make any adjustments to your number. Give your body enough time to really adjust.

Now for those of you who are math geeks and haven't just scrolled through.. option 3 is for you.

Option 3: Hard Core Math (For Math Geeks)

If you love math, this is the method for you. You can get out the Excel sheet and get to work. You've probably seen this method on calorie calculator sites, it's called the Harris-Bennedict Method. This is the method that you can use to determine your Basal Metabolic Rate, which is the amount of calories your body burns being alive.

For men:

BMR = 13.397* (weight in kg) + 4.799*(height in cm) - 5.677*(age) + 88.362

For women:

BMR = 9.247*(weight in kg) + 3.098*(height in cm) - 4.330*(age) + 447.593

The resulting number can then be multiplied by an activity factor to determine your maintenance
calories or your Total Daily Energy Expenditure (TDEE).

Activity Factors:

  • Sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
  • Lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
  • Moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
  • Very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
  • Extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

How to Adjust Your Calories for Weight Loss and Weight Gain

Precaution: Don’t Set Your Calories Too Low

Most people do not need to cut their calories lower than 1300-1500. The exception to this rule is a very short, petite woman, or someone who is bedridden.  Now read that again ladies.. 1200 calories is not enough for you! If you set you calories too low, you will end up failing in the long run. You may lose weight quickly and lots of it, but you will not be able to sustainably keep it off. In addition, most of the initial weight loss that you will lose is only water weight, not true fat mass or even muscle mass.

How to Calculate Your macros

Now that you know how many calories that you need, it's time to figure out how they will break down into protein, carbs and fats. For most people, there are a range of macros that can work.

Protein typically should be set for 0.7-1.0 grams per pound of body weight. I know this sounds like a lot of protein, but protein keeps you feeling full for longer than carbs or fats.

Also, if you are lifting weights at all, you want to make sure your getting enough protein to help your muscles recover and grow. Carbs and fats can be set according to personal preference. 

Although you want to keep your fats around a minimum of 20% of total calories to make sure your hormones don't go crazy and out of whack.

A women who weighs 140 pounds, works a desk job during the day but works out every day after work. Her workout contains some weight lifting and some cardio. She's not actively trying to lose weight at this time.

Bodyweight: 140 pounds
Maintenance Calories: 140*14=1960 (from guesstimate equation above)
Protein: 140lbs x 1 gram= 140 grams protein or 560 calories protein
Fats: 20% x 1960 = 392 calories of fat or 44 grams fat
Carbs = 1960 calories - (560 protein calories + 392 fat calories)= 1008 calories or 252 grams carbs

Carbs will fill up the left over calories that are left. You can always adjust the fats to be higher than 20% if you prefer more fat in your diet, but it's a personal preference how much you allot to carbs and fats after you account for protein.

What to Eat

Now that you know how your calories and macros break down, it's time to figure out what to eat. This is where an app like MyFitnessPal or LoseIt comes in. I personal prefer MyFitnessPal and have for years, but you can really use any app that you like. These apps track your calories and macros and help you hit your daily goals. You can eat anything that you want in moderation, as long as you meet your macros. If you feel better eating only organic whole foods, then go for it. If you prefer to indulge daily with ice cream, go for it. Just make your food fit your numbers. This will take some time to get used to, but over time you learn the portion sizes that are appropriate for you. You will also learn that having a burger and fries for lunch may mean that you have to go a little lighter on breakfast and dinner.

If your app doesn’t allow you to enter specific numbers and prefers that you chose more rounded numbers, round to the closest number that you can. Tracking your calories and macronutrients does not have to be perfect. Manufacturers can have up to 25% discrepancy in the calories that are on the label. If they can have a discrepancy, so can you. Aim to keep it within 5 – 7 grams of your goal.

Let me know which method you prefer in the comments below.