Nutrition experts give the step-by-step guide on how to calculate macros, and more importantly, who really even needs to.

By Megan Falk
April 30, 2021
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How to Calculate Macros
Credit: Alex Sandoval

The 2020s might as well be considered the golden age of health tracking. Your phone can tell you how many hours you've spent staring at its screen throughout the week. Your watch can log how many steps you've taken and floors you've climbed throughout the day. And after downloading an app or two, you can even start tallying the grams of carbohydrates, fat, and protein (aka macronutrients) you're eating down daily.

But do you really need to keep track of your intake of these nutrients? Here, registered dietitians break down how to calculate macros based on your health and goals, as well as the pros and cons of using them to guide your food choices. Spoiler: It's not the best idea for everyone.

What Are Macros?

Macronutrients, or "macros" for short, are the nutrients that your body uses to carry out everyday activities and functions, says Jennifer McDaniel, M.S., R.D.N., C.S.S.D., L.D., owner of McDaniel Nutrition Therapy. The three essentials macros are carbohydrates, fat, and protein, and each plays a unique role in your body. "Everything the body does, from exercise to breathing, requires carbohydrates," says McDaniel. "Fats make up the body's cells, help absorb vitamins, play a role in heart health, and help us feel full longer, while protein helps maintain muscle and bone health, helps control diabetes, and repair cells" — and those are just a few of the many potential perks of eating the right amount of protein, fats, and carbs. (Related: Are Saturated Fats Actually the Secret to a Longer Life?)

There isn't one set-in-stone recommendation for the number of macronutrients you should aim to score every day — plus, your sex, height, weight, activity level, and personal goals all influence your needs, says McDaniel. For women, in general, the United States Department of Agriculture recommends that 45 to 65 percent of calories come from carbs, 20 to 35 percent of calories come from fats, and 10 to 35 percent of calories come from protein, says McDaniel.

These loose guidelines can help you decide roughly how much space on your plate to dedicate to each macronutrient. But some people — such as those trying to hit a health or performance goal or individuals with certain medical conditions — may want to calculate the exact amount of macronutrients they need and pay closer attention to their consumption (more on the reasons why in a bit).

How to Calculate Macros

To figure out exactly how much of each macronutrient you need daily, you first have to find out how many calories you're burning, says McDaniel. (The USDA offers an online calculator that gives you an estimate of your daily caloric need to maintain body weight. Just remember that your needs change based on your activity level.) You'll also need to know how many calories are in a gram of each macronutrient: 1 gram of carbohydrates has 4 calories; 1 gram of fat has 9 calories, and 1 gram of protein has 4 calories, she explains. From there, you'll need to break out a notepad and follow two basic formulas:

  1. Daily Calories Per Macro: total calories per day x percent of calories to come from the specific macronutrient per day
  2. Daily Grams Per Macro: calories of the macronutrient per day ÷ calories per gram of the macronutrient

For example, a person who burns 2,000 calories a day might calculate their macros like this:

Carbohydrates

  • 2000 total calories x .50 of calories from carbohydrates = 1000 calories from carbohydrates 
  • 1000 calories from carbohydrates ÷ 4 calories per 1 gram carbohydrate = 250 grams carbohydrates per day 

Fat

  • 2000 total calories x .30 of calories from fat = 600 calories from fat 
  • 600 calories from fat ÷ 9 calories per 1 gram fat = 67 grams fat per day 

Protein

  • 2000 total calories x .20 of calories from protein = 400 calories from protein 
  • 400 calories from protein ÷ 4 calories per 1 gram protein = 100 grams protein per day 

Again, the grams of carbohydrates, protein, and fat listed here are just general recommendations, and each person's caloric and macronutrient needs will be different, says McDaniel. For example, someone who goes for a run every morning will likely need to fuel up with more carbohydrates than someone who prefers to chill on the couch most days, she explains. (Related: What You Need to Understand About Exercise and Calorie-Burn)

Not to mention, the macronutrient distribution will change based on your health or performance goals, says Molly Kimball, R.D., C.S.S.D., a New Orleans-based dietitian at Ochsner Fitness Center and host of the podcast FUELED Wellness + Nutrition. If you're looking to lose body fat (and wondering how to calculate macros for weight loss), for example, you might dial back on the number of carbs you consume to achieve a calorie deficit, keep your protein consumption the same to maintain and build lean muscle mass, and stick with a moderate fat intake, says Kimball. On the flip side, you might amp up your carb and fat intake if you want to gain weight, she explains. And if you're hoping to build muscle, you'll likely need to consume more calories from carbs and protein, adds McDaniel. 

This variability is why it's so important to meet with a registered dietitian if you want to know how to properly calculate macros and meet your health and fitness goals, says Kimball. After all, your macro targets are beneficial only if the formulas used to determine them take your unique body and lifestyle into consideration, she explains. "Are they custom-tailored for you to suit your needs, or was it a cookie-cutter formula?" she adds. "Carve out some time and a little bit of money to meet with a dietitian and share what your goals are, where you are in your journey, and then have them work with you to put together something that's customized and individualized for you. Then they can also educate you on what these numbers look like in terms of food."

How to Track Macros

Once you have set goals and know how to calculate macros, consider downloading an app, such as Fitbit and MyFitnessPal, to track your intake, suggests McDaniel. There, you'll be able to log your meals and see their nutritional profiles. Just make sure you look for "verified foods," since anyone can add a food on those apps and provide inaccurate nutrition information, which may hinder you from hitting your macro targets, she says.

If you don't want to use an app, go back to the basics and look at your food's nutrition facts label, which will tell you how much of each macronutrient is in a serving, says McDaniel. (This guide will teach you how to properly read a nutrition label if you don't know already.)

No matter which method you choose to track and calculate your macros, though, know that "it's only as accurate as your assessment of how much you have," says Kimball. "If you're putting in half a cup of brown rice, is it really half a cup? And are you filling out the right item in the app — is that the same as what you ate?" Taking the time to log the correct food and portion size is key to hitting the macronutrient goals you and your nutritionist decided upon. (Related: Your Complete Guide to the 'IIFYM' Or Macro Diet)

The Potential Benefits of Tracking Macros

Tracking your macros isn't a necessity for everyone, but certain groups might benefit from doing so, says McDaniel. Regardless of the reason, "calculating your macros lets you know what to shoot for — what your target is," explains Kimball. "There are so many messages and approaches out there and knowing what those numbers are can give someone something to aim at."

People with certain medical conditions, such as type I diabetes, may reference their macro intake to ensure they match the grams of carbs they consume at a meal to an insulin dose, explains McDaniel. Similarly, those with chronic kidney disease will often need to limit their protein consumption to better manage their condition, and tracking their macros can help them ensure they don't go over their recommended intake, adds Kimball.

Someone following the keto diet — which involves sourcing 75 percent of your calories from fat, with 20 percent from protein, and 5 percent from carbohydrates — may also want to track their macros, particularly their carb and fat intake, so their body stays in ketosis (when the body uses fat — not stored glucose — as fuel), says McDaniel. 

Those wanting to lose weight, gain muscle mass, or hit a performance goal may also choose to calculate and keep tabs on their macros, says Kimball. For example, an endurance athlete training for an Ironman race might benefit from tracking their carb intake, which will help them ensure they give their body enough of the energy source it needs to exercise at such an intense level, adds McDaniel.

The Downsides of Calculating Your Macros

A word of caution about calculating your macros to guide your food choices: "Just because you eat 'x amount' of grams of macros doesn't [mean it's] quality," says McDaniel. "If someone is focusing solely on macronutrient distribution of their diet, they could still eat a diet full of processed foods and still meet macro targets." Sure, noshing on protein bars and low-carb, high-fat ice creams could help you hit your recommended macronutrient intake, but those foods may be lacking in fiber and essential micronutrients. 

What's more, sticking to your macro targets requires quite a bit of mental energy, and this preoccupation with numbers can cultivate an unhealthy relationship with food in some people, says McDaniel. "I argue we [already] have enough on our plates to add macro counting to it!" she says. "We prefer clients rely more on internal cues, like hunger, fullness, and emotional satisfaction to food, compared to external controls such as counting grams of carbs or fat." (BTW, that's the basis of intuitive eating.)

To echo that, Kimball adds that "[counting your macros] takes a lot of focus and determination, and unless it's something that you really need to do, I really encourage people to fill their brain space, time, and energy with something else."

So, Should You Calculate Your Macros?

Considering all the commitment and energy required to stick to your carb, fat, and protein targets — along with the practice's potential to do more harm than good — both McDaniel and Kimball recommend only folks who will truly benefit from tracking their macros do so. "You don't need macro counting to eat well," says McDaniel. "Focusing on the quality of your food, which combinations of food help you to feel both emotionally and physically satisfied, trumps counting grams." (You might want to consider stopping counting calories too.)

And if you do choose to calculate your macros after meeting with a registered dietitian, don't let those numbers become your identity, says Kimball.

"Focus on your macros to the extent that it helps you develop a rhythm of eating and food patterns that are sustainable for you," she explains. "But beyond that, be really aware and mindful not to make it an obsession that is edging out very valuable brain space that you could be using for so many other positive things in your life."

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