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Megan Best
Megan Best

RDN, CPT

How do I calculate my own macros?

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What are macros?

Macronutrients aka “macros” are the three nutrients that provide us calories- protein, carbohydrates, and fat. They have become sort of a buzzword because some in the nutrition and/or fitness space have turned them into a diet or a verb (aka “doing macros”) but in reality, they are a powerful teaching tool. Knowing more what your calorie and macronutrient needs should be provides you with the knowledge and power to make dietary choices that will reflect the goals you have and the way you want to feel.

How do macronutrients differ from micronutrients?

Macronutrients provide us calories- protein and carbohydrates are four calories per gram, and fat is nine calories per gram. They also provide us other benefits- protein helps us to feel satiated, build and maintain muscle and provide structure and support for our cells. Fat helps us absorb micronutrients, keeps us full and protects our vital organs. Carbohydrates’ main job is to provide us with energy, though it has so many more functions.

The main difference is that macronutrients are nutrients our body needs in large amounts, while micronutrients are those we need in small amounts. In addition to this, micronutrients do not have calories associated with them, but they provide us with other benefits. Micronutrients, also called vitamins and minerals, help us to develop properly, ward off diseases, and function day to day. Micronutrients, like macronutrients, are not produced in the body and must be consumed daily.

Why track macros?

Tracking macros is just another form of food journaling. There are so many ways to use this tool- visual food journals, paper logs, and calorie counting/macro tracking apps being the three most popular. Any of these three journaling practices can be helpful, and a good way to start with journaling is to use the “hand method”. This allows you to visualize approximate servings before worrying about the numbers associated with them. However, if you have specific goals, then logging calories and macronutrients in a tracking app is the most detailed way to journal.

Here’s the thing: macronutrients are the very foundation of what you are eating. Tracking them provides us with numbers, data, and insight into your diet. It helps us spot nutritional deficiencies, caloric surpluses, or unbalanced meals. Without this data, it can be hard to make changes- because you don’t specifically know what to change.

When I start with clients, I have them journal for awhile (sometimes two weeks, sometimes a month) without goals. We cannot make a change if we don’t currently know where you are and what needs to change! Journaling just to notice behavior and choices really opens people’s eyes up to what they are (or are not) eating, and it can be a helpful tool by itself, without even setting specific numeric goals. Sometimes just the act of journaling and being accountable for the foods a client eats is what they need! But often this period of time gives us insight into where to start in their nutrition journey.

On the flip side, there are some people who should not track macros. Anyone with a history of eating disorder or disordered eating would likely not be a good fit for this methodology. Food journaling could still be helpful, but I would recommend a dietitian who specializes in eating disorder treatment to assist in your nutrition journey.

How to calculate your macros

Calculating your macros starts with calculating energy needs, aka total calories. This is a three step process.

Step 1: Resting Metabolic Rate (RMR)

First we start with calculating your Resting Metabolic Rate (also called Basal Metabolic Rate) aka the calories you need to lay in bed and do nothing. The best way to calculate this is to use Indirect Calorimetry, but this method is not accessible to most. Though it is worth searching your area to see if you have a university or gym that has the equipment to measure RMR! If you are unable to find this, simply use an equation. There are many out there, but I like to use the Mifflin St. Jeour, which is the gold standard in the nutrition world. You can do a quick google to get some background on it, but it is:

Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

For example: if I calculated the RMR on a 160 pound, five foot seven, 33 year old female I would get approximately 1465 calories.

Step 2: Activity

You need to factor in both Non Exercise Activity Thermogenesis (how active you are throughout the day, not including exercise) and Exercise Activity Thermogenesis (any intentional exercise you perform). These can be separated out if you know your precise calorie burn during exercise, but most people are not hooked up to a chest strap heart rate monitor for every workout. Because fitness trackers and wearables are so inconsistent and unreliable, you don’t want to use their data. Instead, use the below chart to calculate what activity adds to your total daily energy expenditure. Be very honest with yourself! Most adults fall somewhere from sedentary to low levels of physical activity.

Source: Sports Nutrition: a Handbook for Professionals.

Choose your activity factor and multiply it by your current RMR.

For example: let’s take the above RMR of 1465 and say she is an office worker who sits most of the day (getting about 7,000 steps), but she does workout three times per week. I would still put her in the “low level” range but towards the higher end- so perhaps I’d multiply by 1.55. This would give me a new number of 2,271 calories.

Step 3: Thermic Effect of Food

The three macronutrients each have an energy expenditure rate associated with them. Fat is about 3% of ingested calories, carbohydrates are 5-10%, and protein is highest at 20-30% of ingested calories (meaning it takes the most energy to burn protein of the three). The average estimated TEF for a mixed meal is 10%, so this is the number I use in my calculations. Simply calculate 10% of the above two steps, and add it to the number you have.

So we take 2,271 x .10 which is 227 calories from TEF. Add that to 2,271 and get 2,498 for total daily energy expenditure.

Now you have your total daily energy expenditure! What’s left to figure out: whether this person’s goal is to build muscle, lose fat, or maintain weight.

Build Muscle
In order to build muscle, we must be in a caloric surplus. I typically add 250-350 calories for clients with this goal.
2,498 + 250 calories = 2,748 calorie goal.

Lose Fat
In order to lose body fat, we must be in a caloric deficit. I typically subtract 250-350 calories for clients with this goal.
2,498 – 250 calories = 2,248 calorie goal.

Important to note: you cannot be in the “lose fat” and “build muscle” categories at the same time, as one requires a caloric surplus and one requires a caloric deficit.

Maintain Weight
This is also the category I like to call the “feel better” category. Often when a person comes to me with a goal of feeling better, they are undereating and we need to get them back up to their maintenance calories.
This would simply be our first TDEE calculation (2,498 in the example).

Calculating Macronutrient Goals

Keep in mind the most important numbers when setting calorie and macronutrient goals are going to be 1) calories and 2) protein. If these are correct and consistently met, fat and carbs become less important, depending on the sports specific needs or disease state of the person. Obviously if we have an athlete, we’re going to be higher carb than fat, but if we are just calculating for an “everyday athlete” (aka someone who works out for health 3-5 days per week) then we can lean heavier on the macro they prefer of the two.

Protein recommendations can vary, but a good general rule to follow is:

Bare minimum need: 0.8g/kg body weight
Physically active: 1.1-1.5g/kg body weight
Training 5+ days and/or want to change body composition: 1.5-2.0g/kg body weight
Elite Athlete: possibly more

As a rule, I like to make sure all of my clients can hit 100g of protein first before giving them heftier goals.

Once you have protein goals, figure out what percentage of your calories they come out to. For example, our 160lb woman is physically active and wants to change her body composition, so I’ll multiply 1.7 x 72.72 kg (her weight in kg) to get 124g of protein.

160/2.2 = 72.72
72.27kg x 1.7 = 124g protein
124g x 4 calories per gram = 496 calories
496 cal/2248 cal = 22% of total calories


Now that we have protein, we have 78% of our calories left to work with. I could simply divide by two and have her eat 39% fat and 39% carbs, or I could dig deeper. I would likely check out her food journal to see if she leans one way or the other AND check out her assessment for past medical history. This is why we need a full assessment folks, not just numbers!

Let’s say we do an equal split. Remember carbs are four calories per gram and fat is nine calories per gram! Her total prescription would look like this:

2,248 Calories
124g Protein
219g Carbs
97g Fat

And that’s how it’s done! Remember, these calculations are highly dependent on a variety of factors going on in your life as well as your medical history, so the BEST option is to consult with a professional. Click here to learn more about my Macro Jump Start, where you get tried and true numbers AND an appointment with me to go over them!

Got questions? Leave them below, I would love to hear them!

Source:
Karpinski, Christine, and Christine Rosenbloom. Sports Nutrition: a Handbook for Professionals. Academy of Nutrition and Dietetics, 2017.

3 Responses

  1. Wow, that was intense. 😂 I’m a bit overwhelmed with all that math. I’ve been using cronometer for about 3 years now and have lost 15+ lbs with it, but I wanted to adjust the macros to better fit “me”. I’ve been plateau-ing at 123 lbs lately. Changing it according to your formula gave me extra calories 😲 for the day. Kinda cool, but really?? I don’t eat meat much anymore; beans, tempeh, tofu, spent grain sourdough bread (homemade of course) and Cheese & greens are about it. No processed food other than the cheese and maybe a beer twice a week. Having extra cals is cool, but am I really calculating correctly? What about factoring age into that formula? I’m no spring chicken at 63. And I can’t really afford $199 right now. The nutritionist I went to here with my insurance didn’t even really look at my cronometer printout. She said I’m doing fine. 🤨 I consider myself moderately active; usually get 11500 steps on my Fitbit. This past week it’s way less because I just had lumbar fusion surgery on the 11th, so slowly getting back to walking around. Today’s count is 8616, but as you said….. these trackers aren’t really correct. It’s an estimate that includes fixing a salad for lunch🤭

    1. Hi Sabine! It’s hard to know your exact needs without knowing your background through a proper session, but I will say that lots of people lose weight successfully by logging and then plateau, often because they’re at a weight that’s appropriate for them. As for the higher calorie needs calculated from my post- this is common, as many people lose weight by going into WAY too deep of a deficit. This also causes us to plateau as we simply cannot keep eating less and less. Make sure you’re not living in a constant state of trying to lose- our body needs to live at calorie maintenance for a large part of the year!

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