How to Calculate Your Macros: Daily Calorie Intake

How to Calculate Your Macros: part 1 Daily Calorie Intake | mamaswithmuscles.com #macros #flexible dieting #caloriesHey everybody! It’s about time I get back to writing!  To continue our conversation about macros and flexible dieting, I am going to show you the basics of calculating your macros manually.  The first step is determining your daily calorie intake.

Figuring Out Your Daily Calorie Intake

First you need to figure out your Basal Metabolic Rate or BMR.  This number is how many calories your body burns when you are doing nothing besides just being alive.  There are several factors that come into play including whether you are a man or a woman, your height, weight, age, lean mass, and activity level.  There are three different equations that we can use to estimate our daily calorie needs. I will use my numbers to show you how these different equations compare when it comes to estimating my BMR.

Harris-Benedict Formula:

Men: BMR=66.47+ (13.75 x W) + (5.0 x H) – (6.75 x A)
Women: BMR=665.09 + (9.56 x W) + (1.84 x H) – (4.67 x A)

In these equations, W = your body weight in kg (lbs/2.2), H = your height in cm (in x 2.54) and A = your age in years.

I will use my numbers as an example…I weigh 120 lbs, am 63″ tall, and I am 28 years old.  So W = 54.54, H = 160.02, and A = 28.

My BMR= 665.09 + (9.56 x 54.54) + (1.84 x 160.02) – (4.67 x 28) = 665.09 + 521.40 + 294.44 – 130.76 = 1350.17

So my Basal Metabolic Rate, or BMR is about 1350 calories per day using the Harris-Benedict Formula.

Mifflin-St. Jeor Formula

According to a study done by the ADA (American Dietetic Association) the Mifflin-St Jeor formula is more accurate than the older Harris-Benedict Formula which may overestimate calories by as much as 5%.

Men
10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5

Women
10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161

Using the same numbers from above my BMR = 10 x 54.54 + (6.25 x 160.02) – (5 x 28) – 161 = 545.4 + 1000.13 – 140 – 161 = 1244.53

Using the Mifflin-St. Jeor Formula my BMR is about 1245 calories per day.

Katch-McArdle Formula

The Katch-McArdle formula is more accurate for those on the leaner side but you have to know your body fat percentage.

Men & Women
21.6 *Lean Mass + 370

Lean or Fat Free Mass = Weight – (Body Fat Percentage * Weight)

BMR = 21.6 x (54.54 – (.16 x 54.54)) + 370 = 21.6 x (54.54 – 8.73) + 370 = 21.6 x 45.81 + 370 = 1359.5

I am estimating my body fat percentage at 16%.  It seems to be fairly accurate because using this formula my BMR is about 1360 calories.

Which Formula?

Remember that no matter which formula you use, these are estimates! No one formula will give the best number for all people.  If you are very lean, the formulas will tend to under-estimate your BMR and if you are over-weight these formulas, especially the Harris-Benedict Formula may over-estimate your BMR.  Honestly you can use any one of these three formulas to get a good starting number to use to start experimenting with flexible dieting and you can always adjust if your total calories seem to be either too low or too high for you to be able to reach your goals.  Or, could also take an average of these formulas.  Finally, there are certain circumstances such as pregnancy and breastfeeding that will require additional calorie adjustments.

I am going to use 1350 as my BMR for the next section.

Accounting For Activity Level

Once you calculate your BMR you need to multiply this number by a factor based on your activity level to account for calories burned during exercise.

Mostly Sedentary/Very Low Intensity = BMR x 1.2

Light Exercise (3-4x per week) = BMR x 1.375

Moderate Exercise (3-5x per week 30-60 mins/session) = BMR x 1.55

Moderate to High Intensity Exercise (6-7x per week for 45-60 mins) = BMR x 1.725

Extremely Active/Athlete = BMR x 1.9

People tend to over-estimate their activity level so be realistic when choosing which factor you use to figure out your daily calorie intake.  For the sake of comparison, I will show you how activity level changes my daily calorie intake using the same number, 1350, as my BMR:

Mostly Sedentary/Very Low Intensity = 1350 x 1.2 = 1620

Light Exercise (3-4x per week) = 1350 x 1.375 = 1856

Moderate Exercise (3-5x per week 30-60 mins/session) = 1350 x 1.55 = 2093

Moderate to High Intensity Exercise (6-7x per week for 45-60 mins) = 1350 x 1.725 = 2329

Extremely Active/Athlete = 1350 x 1.9 = 2565

Once you choose which activity level factor to multiply by, the result is your daily calorie intake for maintenance.  In other words, it’s the number of calories you need to ingest to stay at your current weight (neither losing or gaining weight).

Adjusting Daily Calorie Intake for Goals

Many people use flexible dieting to help them either lose or gain weight.  Obviously, we can’t expect to make a change one way or the other if we use our maintenance calorie intake.  To account for different goals, you will need to use another factor to adjust your daily calorie intake.

Weight-loss

Subtract 10-20% of your maintenance calorie intake to achieve slow/steady weight-loss without losing too much muscle.

Weight-gain

Add 5-10% of your maintenance calorie intake to encourage muscle growth without packing on too much excess body fat.

The next step is to figure out your macro breakdown but you will have to wait until part two for that!

 

 

If you are confused by all these formulas and numbers and are in need of some help figuring out your daily calorie intake or macros please contact me! I am in the process of adding macro/nutrition planning to my online services…contact me to find out more info!

2 thoughts on “How to Calculate Your Macros: Daily Calorie Intake

    • I would classify boot camp as moderate exercise based on the time domain since the classes are between 30-60 mins long and most boot campers are working out between 3-5 times a week. Hope that helps!

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