If It Fits Your Macros Diet—AKA ‘IIFYM’—Pros and Cons


Chances are, you have at least one friend who “counts macros.” IIFYM (“If it fits your macros”) is popping up in photo captions for everything from meal-prepped chicken-and-veggie lunches to dripping ice cream cones, and millions of people are using apps like MyFitnessPal to track calories and macros. But what exactly does it all mean?

Anyone following IIFYM aims to eat a certain set amount of fat, carbs, and protein every day. Beyond that, it’s basically a free-for-all.

First of all, “macros” is short for macronutrients—fat, carbs, and protein. Everything you eat and drink (with the exception of water and alcohol) is made up of some combination of the three. The idea behind counting macros is that you aim to get a set amount of each macronutrient each day. Julie Upton, M.S., R.D., cofounder of nutrition website Appetite for Health, explains that a standard IIFYM breakdown would have you consume 40 to 50 percent of your calories from healthy carbs, 25 to 30 percent of calories from protein, and the remainder from healthy fats. That said, your target macronutrient breakdown may vary depending on personal factors—weight, height, gender, and activity level, etc.—and your specific goal. Someone trying to gain muscle is going to eat differently than someone trying to lose weight, and athletic goals like training for a marathon or working to increase your powerlifting total will also change what your daily macronutrient breakdown might look like. There are no “good” or “bad” foods—everything is fair game, and it’s just a matter of hitting your daily fat, carb, and protein totals.

There’s nothing magical about IIFYM. It follows the same calories in, calories out principle as all successful weight-maintenance and weight-loss diets.

IIFYM fans often post pictures of themselves eating things like chocolate, french fries, and waffles (in addition to healthier foods, of course), making this lifestyle look pretty fantastic. But, is the Insta-worthy, highly hashtag-able If It Fits Your Macros diet worth all the hype it gets? Upton notes that “there is nothing magical” about IIFYM. Yes, it can help you stay fit or lose weight if you follow it correctly based on your goals. But that’s more because it follows a common weight-loss rule than because of something special inherent to the diet: If you stay within your daily caloric budget, you likely won’t gain weight, and if you eat fewer calories than your body needs, you’ll probably lose weight, Sonya Angelone, R.D., a spokeswoman for the Academy of Nutrition and Dietetics, tells SELF.

It’s important to note here that food isn’t the only factor when it comes to weight loss. Things like exercise, sleep, stress, and health conditions all play a part, and the weight-loss process can vary greatly from person to person. Also understand that everyone’s daily caloric expenditure (the number of calories you burn every day) varies, so the number of calories and macronutrient that helps one person reach their goals may not work for someone else.

(Another important note: Weight loss isn’t for everybody, and neither is following a specific, numbers-based eating plan. If your goal is to lose weight, more power to you, but your health matters more than a number on a scale or a tag in your jeans, so it’s crucial to maintain a holistic approach to weight loss, which also includes physical activity, good, quality sleep, stress management, and paying attention to other factors, such as medical issues and hormones. If you have a history of disordered eating, you should discuss any plans to change your diet with a doctor before diving in. The focus on numbers and tracking can absolutely be triggering for some people, and if that’s the case, you should avoid it completely.)

If you’re following a personalized diet template, it’s best to get that template from a registered dietitian or a doctor.

Proponents of If It Fits Your Macros will often buy macronutrient distribution diet templates that divide their total daily calories into daily grams of protein, carbohydrates, and fats. The problem? Many of these templates are coming from Instagram “experts” and “diet coaches” with no real nutrition or health qualifications. This should go without saying, but having a large social following doesn’t make someone an expert. Likewise, an influencer might themselves have great health and nutrition habits, but that doesn’t mean they’re qualified to give others advice on those matters.

As with any major lifestyle change, you should consult your doctor or a registered dietitian before drastically changing your diet or starting a weight-loss program. An R.D. can provide you with a healthy diet template that’s personalized to your body and your goals, if that’s something you’re interested in. If you don’t want to make an in-person appointment, many R.D.s offer online consultations and services. Again, expert guidance is so much more valuable than advice from a popular influencer who lacks real credentials.

The major upside of IIFYM is that it emphasizes the idea that all three macronutrients—fat, carbs, and protein—are important, and doesn’t make any food off-limits.

One great thing about focusing on all the macronutrients, per Upton, is that it keeps people from vilifying (or eliminating) a single group. While low-fat or low-carb diets might lead to weight loss due to a caloric deficit that comes as a result of eliminating so many foods, the USDA’s dietary guidelines stress that, for otherwise healthy people, a balanced diet (containing all three macronutrients) is best for overall health. An IIFYM approach can help people stop fearing carbs and fat.

Plus, IIFYM is less restrictive than many other diets in that no foods are off limits. Alissa Rumsey, R.D., C.S.C.S., explains that a benefit of IIFYM it that it allows you the flexibility to eat your favorite foods while still seeing results.


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