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How to Calculate Macros for Fat Loss

How to Calculate Macros for Fat Loss
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How to Calculate Macros for Fat Loss

By Christine Hronec


One thing a lot of people want to know when they have a fitness goal is, what should their macros be? Now, if you don't know what macros are, macros are macronutrients. All food is broken down into either protein, carbs, or fat.



So, the first thing you want to know in figuring out your macros is how much energy your body needs. Hypothetically, if you were at rest for 24 hours, this value is called your BMR (basal metabolic rate). The BMR is how much energy it takes your body to function when you're not digesting any other foods, you're not doing any other bodily functions other than just existing.

The human BMR is proportional to temperature. Humans or mammals essentially, we're endotherms. This means that our bodies highly depend on our temperature. So, when it's cold out, we shiver. When it's hot, we sweat. So, our bodies are always using energy to adjust our temperature. Now, BMR can be measured in a lab. This requires the body to fast for so many hours, be hooked up to all these devices to monitor your oxygen and CO2 content, or you can use an equation developed by scientists to model it.

Now, the equation that I like to use because, in my opinion, is the most reliable model is called the Mifflin St Jeor equation. 

Click the link to view the visual explanation of this equation - 

Male BMR is 10 (x) the weight in kilograms (+) 6.25 (x) your height in centimeters (-) 5 (x) the age (+) 5

Female BMR is 10 (x) the weight in kilograms (+) 6.25 (x) your height in centimeters (-) 5 (x) the age (-) 161

This is a model that is pretty darn accurate at estimating BMR. Now, it's interesting because the first thing, you're always going to need to know your weight and height. Why? This is because your weight and height say a lot about your mass. The more mass you have, the more energy it takes to fill your body. Age matters because your metabolic rate actually drops with age. So, over the age of 30, your muscle mass decreases by about 5 to 10% per decade. So, you can intercede this by doing strength training and working hard to maintain your muscle mass, but in general, muscle mass does drop 5 to 10% per decade.

Lastly, of course, because gender is going to have an influence on body composition, on average, females have a 5 to 10% lower BMR than males. So, that being said, first thing we want to do is calculate our BMR. I'm going to use myself as an example. Click the link here to view the breakdown of my calculations and more on this topic -

Now, if you want a custom meal plan or you want your macros calculated for you and you need some help getting started, you can visit or you can DM me on Instagram at for more assistance.


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