Does IIFYM Dieting Work? An Evidence Based Review On IF IT Fits Your Macros
IIFY has taken over the fitness world. But does this diet really work? In this evidence-based article, you will discover the answer, so that you can decide whether IIFYM is right for you. Let us dive right in!
What is If It Fits Your Macros (IIFYM)?
IIFYM is not a diet in the traditional sense. It doesn’t label foods as ‘good’ or ‘bad’ or forbid particular foods while praising others. Instead, IIFYM is a flexible eating style that focuses on two things: calories and macros.
When you follow an IIFYM diet, you can eat whatever food you want as long as you reach your daily protein and macronutrient targets, both of which are based on your personal goals and situation.
So, let us say you have to take in 2,000 calories per day. As long as you hit your macro targets, you could get those calories from any source you want, like eggs, nuts, fish, chicken, or beef.
In fact, the eating style even allows you to consume junk food like pizza and French fries as long as doing so fits your calorie and macro targets.
The beauty of IIFYM is that it allows you to customise your diet to your food preferences and lifestyle; and while that may sound too good to be true, people have been getting impressive results with the approach.
Can IIFYM Help You Lose Fat and Build Muscle?
The short answer is yes. IIFYM can help you lose fat and build muscle.
The reason is that this eating style focuses on calories and macros, which are the two nutritional variables that have the most significant influence on your body composition.
Calories, for instance, are the primary driver of body weight changes. If you consume more calories than you burn, you will gain weight. But if you consume fewer calories than you burn, you will lose weight.(1)
In fact, from a weight gain and loss perspective, it doesn’t even matter whether you get your calories from protein, carbs, or fat. As long as the calorie intake is matched, body weight changes are the same.(2)(3)(4)(5)
Thus, since IIFYM has you focusing on hitting your ideal calorie target, it is an effective dieting style for both weight loss and weight gain.
Besides, IIFYM also focuses on macros, the main ones being protein, carbs, and fat. These macros have a significant influence on whether weight lost or gained will be in the form of body fat or muscle mass.
That is especially true for protein. Getting enough of this macro, which is a main focus on the IIFYM diet, helps you to build muscle on a weight loss plan and to maintain muscle when you want to lose weight.(6)(7)
Consuming enough carbs, on the other hand, supports your workout performance. And making sure your diet contains enough dietary fat, supports countless bodily functions, including hormone production.(7)
A Real-Life Example Proving That IIFYM Works
Professor Mark Haub from Kansas State University conducted a fascinating experiment to show that the IIFYM diet works. (It also shows that, contrary to what most people believe, you do not have to eat ‘clean’ to slim down.)(8)
For two months, he ate only junk foods like Doritos, Oreos, protein shakes, and Twinkies while hitting a protein target and maintaining an energy deficit of 800 calories a day.
The result was that he lost 27 pounds and reduced his body fat from 33.4% to 24.9%.
The IIFYM Diet is Easy to Adhere to and Can Prevent Weight Gain
One of the main problems people have with losing weight is not necessarily dropping the pounds; instead, it is keeping them off. It has often been stated that up to 95% of people regain the weight lost within a few months or years.
That is primarily because most diets are not maintainable long-term. Sure, you could plough through a vegetables with tuna diet for a few days or even for weeks, but after that, your willpower will run out.
As a result, you will eventually throw the diet out of the window, higher-calorie foods will re-enter your diet again, and the lost pounds will find their way back into your body fat stores.(9)
The good news?
IIFYM means more flexibility in food choice. That makes it easier to adhere to the diet in the long-term, leading to weight loss results for months and years to come.(10)
The Three Main Downsides of IIFYM
No matter how good IIFYM may sound by now, it does have three downsides:
- If your IIFYM diet only contains junk food, it will be hard to control your calorie intake. That is because foods such as pizza and doughnuts are not satiating and they stimulate the overconsumption of calories.(11)
- Over-relying on junk food, as many IIFYM practitioners are prone to do, can have harmful effects on your health and increase your risk of falling prey to disease.
- Not focusing on food quality can cause micronutrient deficiencies. Since all vitamins and minerals are involved in body composition in one way or another, not getting enough micronutrients can hurt long-term results.
A zinc deficiency, for instance, can down-regulate metabolism and testosterone production, while not getting enough iron can impair workout performance.(12)(13)(14)
The good news?
You can prevent these three downsides by optimising your food selection. So, if you decide to follow an IIFYM diet, make sure that your diet consists of primarily healthy, nutritious foods.
Especially if you want to lose weight, you want to stock up on fruit and vegetables. That is because fruit and vegetables are highly satiating, but only provide a small number of calories.
As a result, consuming more fruit and vegetables makes it easier to control your calorie intake, which helps you to reduce the number on the scale.(15)
The Bottom Line on IIFYM
Whether you want to lose fat or to build muscle, IIFYM is a highly effective dieting style. That is because this approach focuses on the two most essential nutritional factors, which are calories and macros.
However, to make IIFYM work, it is essential that your meal plan consists, primarily of healthy and nutrient-dense foods to support your health and long-term fitness results.
