While many diets are meticulous about which foods you can and can’t eat, how much you can have, and even when you consume it, for some people, the excessive restrictions can be a recipe for failure.
Instead, the IIFYM diet aims to get away from that — focusing on the three most important energy sources needed for our bodies to function properly. We’re talking about protein, carbohydrates and fat (aka macronutrients, or macros). How it works: Calculate your daily caloric needs, then split those calories into 40 percent carbohydrates, 40 percent protein and 20 percent fat, the ratio that IIFYM proponents say is the most effective for muscle growth, fat burning and consistent energy levels.
Keep in mind, there has been some debate on whether or not this diet is in fact more or less effective than “eating clean, ” and if a calorie is a calorie regardless of the macro composition of the diet you’re following. However, some studies support it and numerous individuals have reported success with this diet. If you think IIFYM could work for you, here’s what you need to know.
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If It Fits Your Macros: The Overall Equation
The first step in the IIFYM plan is to figure out how much energy (i.e. calories) your body uses in a given day. The amount of calories you burn just by virtue of breathing and performing other vital functions is known as the basal metabolic rate, or BMR. Below, use the calculators to find out a rough estimate of your caloric needs, based on the Mifflin-St. Jeor equation. Later you’ll adjust this number based on your activity level.
Next, you have to take into account how active you are. Leslie Bonci, MPH, RD, CSSD, LDN Director of Sports Nutrition at the University of Pittsburgh Medical Center, points out that adding calories based on activity level is a guesstimate and not a precise science. That said, there are general ranges she recommends using for men and women:
- Lightly Active = BMR x 1.3-1.4
- Moderately Active = BMR x 1.5-1.6
- Very Active = BMR x 1.7-1.8
Add in calories for your activity levels, and then divide those calories into 40 percent carbohydrates, 40 percent protein and 20 percent fat. Remember that you want every meal to fit this 40/40/20 set-up. If it fits into your macro ratio, you can feel free to eat it.