The Beginner’s​ Guide to the IIFYM Diet

So you have heard about the IIFYM Diet and wondering if it is a legitimate way to lose fat or is it too good to be true?

Serdar Tuncali
Sep 14 · 11 min read
Photo by Dana Tentis from Pexels

Can you really lose fat eating pizza, ice cream, and pop tarts?

Is IIFYM Diet a healthy way to lose fat?

Let’s go over some facts and misconceptions about IIFYM Diet to find out the truth. You will also find out if it’s a good diet for YOU!

What Is IIFYM Diet?

IIFYM stands for If It Fits Your Macros. The diet is exactly what it sounds like. You can eat whatever you want, whenever you want, however much you want as long as the food fits your pre-calculated macronutrients.

IIFYM Diet was born in bodybuilding forums. Novice bodybuilders would constantly ask the seasoned members advice on what they can and cannot eat. The answer was always “you can eat it if it fits your macronutrient goals”. These knowledgeable members started getting impatient answering the same questions and started just typing IIFYM as a response.

The Principle Behind IIFYM Diet

When it comes to body weight and body composition, calories and macronutrients are the most important components(1). The idea behind the IIFYM Diet is that there are no inherently good or bad foods.

Food is just a combination of proteins, carbohydrates, and fats.

As long as you meet you pre-determined macronutrient and calorie goals you will get results no matter what food you eat. So if you want to eat a slice of pizza, look up the macronutrients in the pizza and if you have room for each macronutrient in your budget, feel free to enjoy it without any guilt.

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Advantages of IIFYM Diet

  1. You don’t deprive yourself of your favorite foods.
  2. No need to spend extra money on “healthy” foods.
  3. You don’t need to meal prep for each of your meals.
  4. You can enjoy the food at events and gatherings without guilt.
  5. It is sustainable for the long term.

Disadvantages of IIFYM Diet

  1. You need to weigh, measure and track every meal.
  2. Unlimited options might lead to analysis paralysis.
  3. Making bad food choices may leave you hungry all the time.
  4. It may lead to poor self-control and overeating.
  5. It may lead to having a poor relationship with food.

Now let’s go through each one of the advantages and understand them better.

You don’t deprive yourself of your favorite foods:

If you ever got on a diet, you know that the hardest part is not being able to eat the foods you love. Most diets have arbitrary rules and restrictions that don’t have any scientific reason.

For example, when I got on the Paleo Diet a few years ago, I wasn’t able to eat beans for some reason. They are one of the healthiest foods that are full of fiber and protein and keeps you full. But it is forbidden.

Why? Because our ancestors didn’t eat it. Well, our ancestors didn’t drive cars either and I am not going to ride a horse to work every day. (Technically, they didn’t have to go to work either, so…)

Sometimes being able to have some delicacy may be the difference between going forward and quitting your diet altogether.

You don’t need to spend extra money on “healthy” foods:

Going on a healthy diet may get pretty expensive. Especially low-carb diets that have you eat meat and butter all day. Then there is organic, grass-fed, free-range. You gotta go with the wild-caught fish instead of regular ones.

All those expenses can add up pretty quickly and open a big hole in your budget. Healthy eating doesn’t have to be expensive, but you can definitely save money if you are allowed to eat the cheaper option.

You don’t need to meal prep for each of your meals:

When you are on a special diet full of rules and restrictions, you can’t really eat out. You need to cook everything yourself and put them in containers to take it with you. Especially if you are on a diet that has you eating 6 times a day, you better invest in a large cooler.

When you are on IIFYM Diet, you can be flexible with the foods you eat. You can go out to lunch with coworkers or have lunch at the cafeteria. Prepping meals will definitely save you money and help you stay on track, but occasional eating out is not going to ruin your progress.

You can enjoy the food at the events and gatherings without guilt:

I don’t know about you, but whenever I get on a diet, the universe gives me the middle finger by creating an event I need to attend. A work or family function, weddings, birthdays, a pool party at a friends house always happen within weeks of me starting a diet.

Now you don’t have to quit your diet or show up your friend’s birthday with a food container. You can plan your meals ahead and enjoy the food that is served at the event.

It is sustainable for the long term:

When you don’t need to restrict yourself, it is easier to stay on the diet. Most people quit their diet because they give in to their cravings and eat something forbidden. Even though that doesn’t make a difference in the grand scheme of things, they feel like they got off the wagon.

If you follow IIFYM Diet, you can just track the food you ate, keep everything in budget, and move forward as nothing happened.

Now let’s discuss the disadvantages of the IIFYM diet one by one.

You need to weigh, measure and track every meal:

The reason IIFYM Diet is very successful is that you meticulously track your food and make sure you eat exactly the amount of food you are supposed to eat to lose fat. This requires you to read the nutrition label, pay attention to serving sizes, weigh and measure your food, and track everything you eat.

Once you get used to it and learn how to use the tools, it really doesn’t take much time or effort. But for someone just beginning, the learning curve may be annoying and tracking may be confusing. I have seen some people quitting because it was so hard for them to track their intake.

Unlimited options might lead to analysis paralysis:

Sometimes it is easier when someone tells us exactly what to eat and how much to eat. Some diets remove most of the options off the table that you are left with a few options to eat.

When you are on IIFYM Diet, your options are literally unlimited. This may be incredible for some people, but sometimes having to make a decision every meal can be exhausting.

Making bad food choices may leave you hungry all the time:

A study has divided the subjects into two groups. Both groups could eat as much as they wanted in an open buffet setting. The first group had unprocessed whole food options and the second group had ultra-processed junk food options (2).

The calories and macronutrients were matched between food options. The group who ate ultra-processed foods ended up eating an extra 500 Calories a day, thus gaining more weight.

This means that if you eat too much ultra-processed junk because you are allowed to, you will end up feeling hungry.

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It may lead to poor self-control and overeating.

When you eat overly processed food, it may be hard to stop when you need to. These foods are engineered to be over consumed. Therefore, it maybe difficult to eat a small amount and be satisfied.

To avoid overeating, only take the amount of food you planned to eat with you.

For example, if you eat chips out of a bag, you will end up eating much more than you are supposed to. Instead, weigh out the chips, close the bag, and only eat the chips you weighed out.

It may lead to having poor relationships with food:

I actually hesitated to put this on as a disadvantage. Because IIFYM Diet can actually help you develop a good relationship with food. Since you don’t need to be afraid of any food or food group, you won’t feel bad having certain foods.

On the other hand, IIFYM Diet may enable some people to make bad food choices.

Technically, you can meet all your macronutrient target by drinking protein shakes, fiber supplements, and eating junk food all day.

Most people won’t feel good by eating like this, but if you ever had an eating disorder, this diet may not be ideal for you (3).

Is IIFYM Diet Healthy?

Health effects of food are still being studied and micronutrients matter more than macronutrients when it comes to health aspects of food (4).

However, there is no consensus on what foods are healthy. There are popular diets on either end of the spectrum and they both site research supporting their theories.

You can watch a Netflix documentary and become vegan. A couple of weeks later, you can read a book and get on the carnivore diet. There is literally no food that both diets agree upon.

So a vegan and a carnivore can’t share any dishes, but they both insist on being the healthiest diet.

So when it comes to health, being agnostic and relying on peer-reviewed studies is still the best approach. Eating mostly plant-based, fiber-rich foods with some lean animal protein along with healthy fats seems like advice most sane nutritionists and dieticians agree upon.

Since IIFYM technically allows any kind of food, it may be unhealthy. That being said, most people who follow IIFYM Diet eat healthier than average. How come?

Let me use a finance analogy to help you understand.

An average American takes home about 3–5 thousand dollars each month. You can lease a brand new Lamborghini for about $2,000. So technically, an average American can afford leasing a Lamborghini. Why don’t we see more Lamborghinis on the road then?

Because if you make $5,000 a month and lease a Lambo, you are going to have to live in a one-bedroom apartment, eat rice and beans every day, cut your own hair, and work until the day you die.

Eating junk food on the IIFYM diet feels the same way. Since you have to adhere to your dietary budget, you think twice when you want to eat pizza or ice cream. I can eat this pizza now, but that means I have to eat chicken breast and broccoli for the rest of the day.

People who follow IIFYM Diet are very careful about their indulgences. Since you need to be on poverty macros to lose fat, you have to be very careful about where to use those macros and whether it will be worth it.

Losing fat alone will improve your health regardless, so as long as you meet your macros and lose fat, you will be healthier. Furthermore, you will most likely go for healthier food options most of the time to meet your macros and feel full at the same time.

Photo by Aleks Magnusson from Pexels

How to Start the IIFYM Diet?

The first step to start the IIFYM Diet is to calculate your calorie and macronutrient needs.

For example, if you weigh 200 pounds, you need to eat between 2,000–2,400 Calories a day to lose fat.

Then you need to calculate your daily protein needs. An easy number to aim for is 1 gram per pound of body weight. For a 200-pound person, that is 200 grams of protein a day.

You can set your fat intake 20–30 percent of your total daily calories. If you eat 2,000 Calories a day, 20% would be 400 Calories. Each gram of fat is 9 calories, so that is about 45 grams of fat a day.

The rest of the calories will come from carbohydrates. Each gram of protein and carbohydrate is 4 Calories. So let’s calculate your carbohydrate needs:

200 grams of protein is 800 Calories.

Plus 400 Calories from fat equals 1,200 Calories. 2,000–1,200=800 Calories.

800/4=200 grams of carbohydrates.

Once you calculate your macros, plan your daily meals and track them with a smartphone app such as MyFitnessPal. Aim to get 80% of your calories from unprocessed whole foods and 20% from indulgences.

Instead of having a reactive approach, track your food proactively. Don’t track after you already ate it, but plan what you are going to eat and enter it into the app. This way you see how much wiggle room you have for portions and indulgences.

I see many people track after they eat and at the end of the day ask for food recommendations for their leftover macros. If you are eating a slice of bread or a tablespoon of olive oil just to meet your daily macros, you are doing it wrong.

You can also decide on your meal timing. If you enjoy larger portions of foods, give intermittent fasting a try. This way you can save most of your calories for the end of the day and enjoy a big dinner.


IIFYM Diet is not a diet but rather an anti-diet. Instead of having rules and restriction, it gives you freedom.

Weighing, measuring, and tracking your food is non-negotiable with IIFYM Diet.

You can technically eat unhealthily and still lose fat with IIFYM Diet, but it gets old really fast. Best way to use IIFYM Diet is to eat healthy, whole foods and fit small indulgences into your diet for sustainability purposes.

When you start your IIFYM Diet, chances are you won’t have enough room in your macro budget to enjoy pizza, ice cream, and junk food in large quantities.


  1. Sacks, F. M., Bray, G. A., Carey, V. J., Smith, S. R., Ryan, D. H., Anton, S. D., … & Leboff, M. S. (2009). Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. New England Journal of Medicine, 360(9), 859–873.
  2. Hall, K. D., Ayuketah, A., Brychta, R., Cai, H., Cassimatis, T., Chen, K. Y., … & Fletcher, L. A. (2019). Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell metabolism.
  3. Levinson, C. A., Fewell, L., & Brosof, L. C. (2017). My Fitness Pal calorie tracker usage in the eating disorders. Eating behaviors, 27, 14–16.
  4. G Engel, M., J Kern, H., Brenna, J., & H Mitmesser, S. (2018). Micronutrient gaps in three commercial weight-loss diet plans. Nutrients, 10(1), 108.

Originally published at on September 14, 2019.

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Serdar Tuncali

Written by

Scientific approach to fat loss and body transformation. Self-experimenting and researching various methods and reporting on

The Startup

Medium's largest active publication, followed by +540K people. Follow to join our community.

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