Ask the Dietitian: Are Macros Important For Weight Loss?

Sidney Fry, MS, RD
by Sidney Fry, MS, RD
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Ask the Dietitian: Are Macros Important For Weight Loss?


Carbohydrates, fat and protein make up the three macronutrient categories in food. These three categories provide us with the bulk of our energy in the form of calories. Carbs and protein each provide 4 calories per gram, while fat delivers 9 calories per gram — important details if you choose to begin counting your macros. Micronutrients, on the other hand, refer to non-caloric nutrients like vitamins and minerals. Many foods contain more than one macronutrient, but the idea behind counting macros or IIFYM (If It Fits Your Macros) is most foods skew more heavily toward one or two. Brown rice, for example, is mostly carbohydrates; salmon is mostly protein; olive oil is mostly fat.


To count macros, you’ll need an online calculator such as MyFitnessPal. You can use the app to log your calorie intake, set target macros (based on your goals and fitness level) and view your daily progress.

The ultimate premise behind counting macros or IIFYM is you can eat pretty much anything you want and still lose weight as long as you stick to your daily macro goals. But what can sometimes get lost in the word macros, is quality. When counting macros, it’s important to recognize some versions of carbohydrates, protein and fat are better than others. For example, whole grain is better than refined; grass-fed meats are better than meat treated with antibiotics; monounsaturated fats are better than saturated.


In general, people who count macros tend to eat fewer carbohydrates, with an emphasis on protein. By setting a goal for exactly how many grams of protein, carbohydrates and fat you consume each day, you’re setting yourself up for better weight-loss success. Unlike restrictive diets, counting macros allows for more flexibility, potentially enabling you to have success with a wider range of foods for a longer period of time.

However, simply hitting your macro goals doesn’t necessarily mean you and your diet are healthy. Search #iifym on any social media outlet and you’ll likely land on countless images of donuts, pizza, giant stacks of pancakes, candy bars and even fast food. But, if you look at counting macros as a way of teaching your mind about the impact each macronutrient has on your body — looking at the food itself rather than the calories it contains, and shifting your mind to think about eating the right amounts and right sources of protein, fat and carbs — then you’ll likely find success in this way of eating.


Counting macros takes a bit of a trial-and-error to find a ratio that works best for you. Part of the beauty of IIFYM is you can modify your macro numbers as your body and goals change.

Here’s a general guideline to get you started, but it’s always a good idea to work with a nutritionist who can take into account your body type, goals, activity levels and medical history:

  • If you exercise for 1 hour or less daily: 30% high-quality protein, 30% healthy fats, 40% healthy carbs
  • If you exercise for 1–2 hours daily: 30% protein, 25% healthy fats, 45% healthy carbs
  • If you exercise for 2+ hours daily: Consider seeing a certified sports dietitian or specialist. You’ll need a more personalized plan to lose weight healthfully when exercising at a high intensity.


Counting macros can help you reach your fitness goals, but it’s important to listen to your body.  If you’re hungry, try adding either more protein or heart-healthy fats, which are more satiating. If you’re tired, add more fibrous veggies to ensure sufficient energy from carbs. If you’re not losing weight, try slightly lowering your carbohydrate intake, especially later in the day. If you’re looking to increase muscle mass, add more protein — and strength training to your routine.

About the Author

Sidney Fry, MS, RD
Sidney Fry, MS, RD

Sidney is a two-time James Beard Award-winning food and nutrition writer, editor and mom based out of Birmingham, Alabama. A registered dietitian with a passion for research and being proactive about health, she loves to eat, write, run and create simple, tasty meals with whole-food-based approach. Find out more from her website, Instagram or Twitter.


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