How To Calculate Macros for Faster Weight Loss, According to an Expert

You’ve probably heard the term “calories in, calories out” when it comes to weight loss—the idea that if you eat fewer calories than you burn, the pounds will melt away. But while this simple formula is appealing, experts are deviating from the decades-old model.

A specialist from Harvard Medical School calls this calculation “not only antiquated, it’s just wrong,” and research consistently concludes that focusing on calorie intake alone has only a short-term influence on your weight. (Research suggests that counting can have troubling effects on individuals’ mental health, too.) 

Enter macros. If you’ve heard the buzz around calculating macros for weight loss, it might sound similar to calorie counting—but this strategy goes beyond that. “Counting calories is less ideal than macros, in my opinion,” says Julia Zumpano, RD, a registered dietitian with the Cleveland Clinic Center for Human Nutrition. “Although it is important to be aware of your caloric intake, putting too much emphasis on calories does not provide enough attention on where those calories come from.” 

For instance, Zumpano explains, “If you consume your suggested calorie intake but are consuming processed foods and sugary drinks, you could essentially lose weight—but you would not meet your nutrient needs and could contribute to negative health outcomes due to poor choices.” 

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What are macros?

Macros is a term that’s short for macronutrients: The three main sources of energy that we get from food, Zumpano says.

These include:

• Carbohydrates, our body’s main source of energy.
• Proteins, essential for building our body’s muscle mass, tissues and organs.
• Fats, which provides essential fat-soluble vitamins and is the most calorically dense source of energy. 

Take any food or beverage, and you can break its calories down into one—or a combination of—these macronutrients. SweeTarts candy would be an example of a single macronutrient food item, where all of its calories are in the form of carbohydrate: Sugar. On the other hand, almonds contain calories in the form of all three macronutrients. 

Still, the calories from an apple primarily come from carbohydrates, like SweeTarts. But eating a 100-calorie apple instead of 100 calories in SweeTarts nets you a range of other vital nutrients, vitamins and minerals—and that’s the main point of counting macros over calories. 

“For someone who counts calories, they are just worrying about the total amount of food in calories they are eating,” explains Gianni Vigliotti, a personal trainer and nutrition coach certified with the National Academy of Sports Medicine (NASM). The advantage of tracking macros is that you can see where your calories are distributed, which helps with awareness around having healthy, nutritious, balanced meals, he says. “You can also set macro targets to help achieve a desired goal.” 

What is the best macro ratio for weight loss?

The Food and Nutrition Board of the Institutes of Medicine (IOM) has set broad recommendations for macronutrient composition that are appropriate for most people. 

If you’re eating a 2,000-calorie-per-day diet, the spread looks like this:

• 45-65% (900 to 1,300 calories) from carbohydrates
• 10-35% (200 to 700 calories) from protein
• 20-35% (400 to 700 calories) from fats

However, says Zumpano, the IOM acknowledges that individual needs vary, particularly based on factors such as age, gender, activity level, and food preferences.

A bodybuilder is more apt to have a diet with a higher protein content to increase the desired muscle development, as detailed in this 2019 nutrition study, while a long-distance runner may favor a larger carbohydrate content for more sustained energy.

When it comes to macros for weight loss, Zumpano’s go-to ratio is 40% of calories from carbs, 30% from protein, and 30% from fat, “but I adjust this [ratio] often based on my assessment with the patient.” 

For instance, she may give an inactive, post-menopausal woman a slightly higher percentage of fat and less of a protein requirement (such as 25% protein and 35% fat) to provide her with more satiety. For a very active middle-aged male, such as a runner or cyclist, she’d recommend more calories from carbs and less from fat or protein.

“I also see what categories of foods they prefer and which they are deficient in to make my final recommendations.” 

How do I calculate my macros to lose weight?

Vigliotti says that to calculate your macronutrient targets, you first need to figure out how many calories you should be eating each day. Approximating your basal metabolic rate (BMR) is a good place to start—this reflects the amount of calories you burn at rest each day.

The only way to get your exact BMR is in a laboratory setting. However, you can get a good estimate using a well-regarded BMR equation, such as the Mifflin St Jeor formula. This tool calculates your BMR and then adjusts it based on your activity level, giving you a reliable idea of how many calories you should consume daily for your lifestyle.

It looks like this:

Once you have your daily calorie estimate, you can determine the total number of grams of each macronutrient you should eat. To do this, Zumpano says, you need the macro ratio you’ll use and convert your calories into grams for each macronutrient.

Calculate your macros for weight loss

Here’s an example dietary plan based on Zumpano’s weight-loss macronutrient ratio of 40% carbs, 30% protein, and 30% fat for someone with a 2,000-calorie-per-day diet:

Carbs—40%: 

• 40% of 2,000 calories (2,000 x 0.4) = 800 calories from carbs daily.
• There are 4 calories per gram in carbs—so divide 800 by 4 = 200 grams of carbs.

Proteins—30%:

• 30% of 2,000 calories = 600 calories of protein daily.
• There are 4 calories per gram in protein. 600/4 = 150 grams of protein.

Fats—30%: 

• 30% of 2,000 calories = 600 calories of fat daily.
• There are 9 calories per gram in fat = 600/9 = 67 grams of fat. 

This means you should be eating 200 grams of carbs, 150 grams of protein, and 67 grams of fat while sticking within 2,000 calories. 

How do I track macros in my diet?

These days, you can track your macros with certain apps. MyFitnessPal, for instance, has a robust food and beverage library containing macronutrient values, so you can visualize how close you are to hitting your macro targets each day.

You can also track your macros manually by reading food labels and calculating grams of each macronutrient per serving using the formulas above. 

Either way, precision is key. “Measuring food is the only way to get a pretty accurate count on macros,” Vigliotti says. “When many people log, they don’t realize that it could be more or less than they [estimate].” He says that calorie counts on food labels and databases are usually averages. “So you might log you had an apple, but was it a medium-sized apple, a large apple? Day-to-day, these might not be significant, but over a month span, those extra or missing calories add up.” 

Zumpano explains that it’s also important to create sustainable dietary habits around counting macros. “Take your specific needs and lifestyle into consideration.” She says that using macros to create a meal plan is ideal, attainable and ultimately the most sustainable way to go. 

Alcohol and macros

Although food and beverages consist of these three calorie-containing parts, one additional calorie contributor should be noted: Alcohol. 

Alcohol holds no nutritional value and is more calorically dense than carbohydrates or proteins. There are seven calories per gram of alcohol—and these excess, empty calories can disrupt your weight loss goals. 

Here’s one basic way drinking alcohol can contribute to weight issues: When you consume alcohol, your body will prioritize metabolizing it because it recognizes alcohol as a toxin. This means your body prioritizes these nutrient-deficient calories (that contribute to your daily allotment) over more important nutrients.

In addition, it has been shown that alcohol consumption can lead to poorer overall food choices (we usually regret that late-night pizza in the morning!). That’s why if you’re trying to lose weight, abstaining from or minimizing alcohol intake is one major key.

The takeaway

Although calculating your daily macronutrients takes time and a little discipline, it can be a valuable habit to build. Working with a professional can ease the burden of determining these numbers while moving you more effectively toward your weight loss goals.

Remember: Not all macronutrients are created equally. Like SweeTarts versus apples, 30 grams of a simple carbohydrate like refined sugar will affect the body differently than 30 grams of a complex carbohydrate from broccoli. Counting macros makes it easier to ensure balanced nutrition than simply counting calories, but it’s still important to pay attention to where your macronutrients are coming from.

Additional writing and reporting by Leslie Finlay, MPA.

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