What is Flexible Dieting? IIFYM Explained

Dieting concept. Young Woman choosing between Fruits and Sweets

Quality over quantity? Not with flexible dieting.

Also referred to as IIFYM (If It Fits Your Macros), flexible dieting is a nutrition plan originally followed by bodybuilders and fitness competitors that allows you to eat whatever you want and not have it effect your body composition or performance, as long as it fits into your daily calorie and macro needs. Example: Can I eat this slice of pizza? Sure, if it fits your macros (get it?)

Let us explain: IIFYM is based on the principle of “calories in, calories out” combined with the idea that eating the exact ratio of macronutrients (carbs, protein and fat) for your body, regardless of their source, will not cause you to gain weight or body fat. As long as you don’t exceed your total caloric and macronutrient ranges for the day, you can eat virtually whatever you want.

Flexible dieting is essentially the opposite of clean eating, which emphasizes eating healthy, quality foods over the quantity of them. Flexible dieting, on the other hand, puts strict parameters on how much you can eat, but what you eat is up to you. Those who struggle with strict diets think flexible dieting is a miracle, while strict dieters feel it’s simply a way to justify eating junk food, which serves nothing in terms of health.

To quickly answer your question: flexible dieting works. Some of the most shredded physiques follow the IIFYM way of eating and they are doing photoshoots and taking home trophies year round. However, it’s important to remember a low body fat percentage does not equal a healthy body. Eating a diet high in junk food and low in nutrient dense foods will have negative effects on your health, even if it doesn’t effect your waistline.

But the point isn’t necessarily to eat junk food all day long, and is actually quite difficult to do and still stay within your macros targets. Flexible dieting is more for your sanity and to teach you a sustainable approach to eating. Diets fail every day because they are too strict and aren’t realistic, and most of the time, any weight that was lost will be gained right back, if not more. Studies show that diets have an almost 95 percent failure rate.

Allowing people to eat the foods they love in moderation makes them less likely to cheat, binge, or quit. In fact, flexible dieting eliminates the need for cheat meals completely. With IIFYM, you aren’t cheating at anything; you are eating the food you want and living your life.

The biggest downside? You have to weigh and track every bit of food that goes into your mouth.

How it Works

The premise is simple: Think of flexible dieting like a daily budget, and your metabolism and your activity level dictate how big your budget is. More active people and faster metabolisms will have bigger calorie budgets for their macronutrients, while less active people with slower metabolisms won’t have as much to work with. All the more reason to get in your workouts, right?

First, you must find your BMR using an online calculator. Your BMR is how many calories you burn a day just to stay alive.

Next, take your activity level into account and do a little math:

Lightly Active = BMR x 1.3-1.4
Moderately Active = BMR x 1.5-1.6
Very Active = BMR x 1.7-1.8

This is your daily calorie allotment. If you want to lose weight, subtract 500 from that number to lose a safe 1-2 pounds per week. Using this calorie allowance and the ideal macronutrient split of 40 percent carbohydrates, 40 percent protein and 20 percent fat, you will want to consume 40 percent of your daily calories from carbs,  40 percent from protein and 20 percent from fat.

So, say you are active and lift weights often, putting your BMR at 2000 calories per day. That means you get 800 calories for carbs, 800 calories for protein and 400 calories for fat.

Now, because it is much easier to weigh your food and count grams, you need to  do just one more bit of math:

To figure out how many grams of each macronutrient you should be consuming each day, divide the calories allotted to each macro by how many calories are in each gram of that individual macronutrient:

Carbohydrates: 800 calories/ 4 calories per gram = 200g of carbs per day

Protein: 800 calories/ 4 calories per gram = 200g of protein per day

Fat: 200 calories/9 calories per gram = 22g of fat per day

So, using our example, you should consume 200 grams of carbs, 200 grams of protein and 22 grams of fat per day, while staying under 2000 calories. As long as your food choices fit those macros and you hit those numbers without going over, you can enjoy whatever foods you’d like without having it affect your body fat percentage. To find the macronutrients in the food you eat, MyFitnessPal.com is by far the most popular resource and allows you to track your macros for the entire day as you log your food, so you know how many grams of what you have left to work with and can plan your meals accordingly.

Sounds like a lot? It is. Some people love the math, numbers, tracking and counting, and for them, flexible dieting may be the answer. If you’re zoning out, rolling your eyes, confused beyond belief or are thinking “ain’t nobody got time for that!” it probably isn’t for you and that’s fine. Food should fuel you, not consume your life.

Also Read:

Online Calorie Counters: Comparing Resources

Decoding Nutrition Facts Labels

One Response to What is Flexible Dieting? IIFYM Explained

  1. Dawn says:

    Hi, quick point out. Your math is wrong.
    When you give the example of a 2000 calorie diet, you go on to say that carbs are 800 calories/ 200 grams, protein is 800 calories/ 200 grams, and that fat is 200 calories/22 grams.
    But the example of 2000 calories a day would make the fat come in at 400 calories/ 44 grams a day, double what you are showing.

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