What to Know About Macronutrients

The lowdown on carbs, protein, and fat.


You’ve probably heard the word macronutrients before, or maybe you’ve seen your favourite IG fitness follows talk about foods “fitting into their macros.” The truth is, you’re already eating macronutrients every day. But have you ever wondered, what actually are macronutrients and why do so many people count them? This explainer offers what you need to know, including why you need macronutrients for better health and performance.

Macronutrients: What They Are and How Much You Need

The word “macros” is simply short for macronutrients, which refers to carbohydrates, fats, and proteins. “They are referred to as macronutrients because we need them in larger amounts than micronutrients, which include vitamins and minerals,” explains Cynthia Sass, M.P.H., a registered dietitian and performance nutritionist.

Pretty much everything we eat is made up of some form of macronutrients, plus also typically micronutrients. You’ll find carbohydrates in foods like whole grains, fruits, and veggies; protein in foods like legumes, nuts, and meat; and healthy fats in foods like olive oil, avocados, and fatty fishes. You need these macronutrients to support your muscles on the run, fuel your energy levels, and for everyday functioning of your brain and body.

According to the U.S. Department of Health and Human Services, carbohydrates should account for about 45 to 65 percent of adults’ total daily calories, protein should make up about 10 to 35 percent of total calories, and total fat should account for about 10 to 35 percent of total calories.

An individual can calculate their own macronutrient needs as a percent of the total calories they consumed. “So for example, if you’re a middle-aged, 60kg active individual and average gym goer following a 1600-calorie diet, you want about 40 percent of your calories to come from carbs, 30 percent from protein, and 30 percent from fat,” explains Sass. These ratios would be typical for individuals that don’t train for a living, or people who are active, but not hardcore endurance athletes. Here’s how those calculations would look:

1600 x 0.40 = 640 calories from carbs
1600 x 0.30 = 480 calories from protein
1600 x 0.30 = 480 calories from fat

To covert those calorie numbers to grams, you divide the carbs and protein by 4, because both carbs and protein provide 4 calories per gram, explains Sass, and the fat by 9, because fat provides 9 calories per gram. Here’s how those calculations would work:

640 / 4 = 160 grams of carbs
480 / 4 = 120 grams of protein
480 / 9 = 53 grams of fat

Depending on your goals, your macronutrient ratios will change accordingly. “It’s important to consider your level of activity and what type of exercises you do,” explains Jennifer Silverman, M.S. in health promotion management and certified nutrition specialist. “For example, anyone who does more strength training will need to increase their protein intake to support proper muscle recovery and prevent injury. Whereas, anyone who focuses more on cardio will need to increase carbs to prevent depletion of glycogen stores.”

The easiest way to calculate the macronutrient levels that work best for your lifestyle? Silverman suggests inputting stats into a macro calculator website, which will ask you for things like age, height, weight, gender, activity level, goal weight, as well as how often and intensely you lift weights. She recommends If It Fits Your Macros (IIFYM), which also asks how soon you’re looking to hit your goals, or Healthy Eater, which is simpler, but yields similar calculations.

The Benefits of Counting Macros

One positive of eating according to your macros is that each macronutrient performs a unique function, explains Sass. As runners or endurance athletes, it’s important to get enough carbs in order to prevent hitting a wall, but without overdoing it in that it leads to GI distress. “The goal is to hit the just right amount of each, so you don’t fall short or surpass your body’s needs,” Sass says.

By achieving that balance, your body will perform at its peak level, and you’ll also recover properly. Plus, your other systems—like your immunity, digestive health, and sleep—will be fully supported. “I like to think of it as the just right amount of workers showing up in the body to perform their respective jobs and keep everything in good working order,” says Sass.

Of course, those “jobs” will depend on your activity level and goals. “If you’re an athlete, macros are incredible important for performance,” agrees Silverman.

Plus, by eating according to macros, you don’t have to cut out any major food groups or deprive yourself—you need a balance of all three macronutrients and that comes from a range of different food sources.

That being said, whether you choose to count macros to lose fat, gain muscle, fuel performance, or for a different reason, the sources and quality of your food choices are really key, explains Silverman. “I’ve seen ‘macro counters’ go all out, pounding donuts because it ‘fits their macros,’ but they certainly don’t feel as good or perform as well as they would had they opted for sweet potato or more nutrient-dense carb options,” she says.

The Downside to Counting Macros

With a macro diet, the goal isn’t to deprive yourself, but rather to fuel yourself properly in order to make your body more efficient. The downside is that counting macros can be time consuming and can sometimes lead to disordered eating. Not only do you have to know your ratios, but it also typically requires you to measure out your food, using a food scale.

So, if flexibility in your diet choices is something you need and enjoy—and the idea of weighing your food at every meal and snack is less than appealing—counting macros may not be the right option for you. Instead, just focus on a balance of all three macronutrients, with slightly more focus on those fuel-providing carbohydrates that’ll power your runs.

Also, monitoring, tracking, and weighing out everything you eat may create and/or perpetuate an unhealthy relationship with food. If you’re a very numbers-oriented person, and you find satisfaction in keeping tabs on your diet, then more power to you. But if you’ve suffered from disordered eating or suspect you might have an issue with it, counting macronutrients probably isn’t the healthiest habit for you.

You want to enjoy your food, not just count every bite that goes into your body. So do what works best for you.

The bottom line: Just like every other diet out there, counting your macros or the IIFYM diet are not silver bullets. Focusing on macronutrients can help your body function efficiently and might even help you meet certain goals, but remember that the quality of what you eat is most important.

As an athlete, your diet is only one part of the performance equation, so the best thing to do is find what works with your lifestyle and what you can sustain longterm. Remember that carbs, protein, and fat—all the macronutrients—are important to a healthy lifestyle. So it’s important to get a mix of all of them, focusing on whole foods to make it happen.

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