If it fits your macros – simple guide

What if I told you can lose weight while eating pizza and burgers every day?


  1. If it fits your macros (IIFYM) – it’s a lifestyle based on eating around specific macronutrients
  2. No food restrictions – you can eat anything you want as long as you hit your macronutrients
  3. Calculate your macros
  4. Use apps to track food
  5. Combine IIFYM with intermittent fasting to eat burgers every day


With If it fits your macro (IIFYM) lifestyle is possible to eat everything you want and still reach your goals whether you want to lose or gain weight.

Yes, I see IIFYM as a lifestyle because there are no restrictions to your food choices, that is why it is often referred to as flexible diet, you can actually eat anything you want.

What is it

IIFYM is an eating habit that has no food restriction.Unlike all the other diets that makes you eat mostly boring foods, IIFYM allows you to eat all the foods you enjoy.

You can basically eat anything you want as long as “it fits your macros”.

What is “macros”? Macros is a abbreviation for macronutrients.

There are 4 macronutrients: proteins, fats, carbohydrates and alcohol.

IIFYM means eating around your set macronutrients for the day. Sounds complicated? I’ll explain you everything below.

How to set up your macronutrients

Believe it or not eating broccoli can make you fat as much as eating chocolate.

There is no specific food that makes you fat. It’s the quantities that you eat on a daily basis.

The main factor that makes your body gain or lose weight is the balance between the energy used by your body to function and the energy resulted from the food you eat.

Macronutrients are setup up according to your daily calories requirements.

The total energy used by your body to function is called TDEE = total daily energy expenditure.

TDEE is estimated based on you basal metabolic rate (BMR) and your level of activity.

The BMR is determined considering your weight, height, age and gender.

The BMR is representing the estimated calories that your body burns so your vital organs function (hearth, lungs, nervous system, kidneys, liver, intestine, sex organs, muscles, brain and skin).

What will make you lose/gain weight is being CONSTANTLY on a caloric deficit/surplus.

While you can easily determine how many calories you eat in a day by weighing every food, calculating exactly how many calories your body burns to function is impossible.

Having said this, there are some formulas that can help you evaluate the BMR:

  • The Original Harris-Benedict Equation
    • Men BMR = 66.4730 + (13.7516 x weight in kg) + (5.0033 x height in cm) – (6.7550 x age in years)
    • Women BMR = 655.0955 + (9.5634 x weight in kg) + (1.8496 x height in cm) – (4.6756 x age in years)
  • The Revised Harris-Benedict Equation
    • Men BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
    • Women BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)
  • The Mifflin St Jeor Equation
    • Men BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5 (measured in Kcal/day)
    • Women BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161 (measured in Kcal/day)
  • The Katch-McArdle Formula (Resting Daily Energy Expenditure)
    • BMR = 370 + (21.6 x LBM); LBM = lean body mass in Kg
  • The Cunningham Formula (RMR)
    • BMR = 500 + (22 x LBM); LBM = lean body mass in Kg

You can find out what is your lean body mass with the following formula:

LBM = weight x (1-body fat %)

Say you have 70 kg and 20% body fat -> your LBM = 70 x (1- 20/100) = 56 kg

Now that you know how to estimate your BMR, you can further calculate your TDEE.

Your body consumes additional calories for your daily activities such as eating, walking, studying, working, exercising, reading etc. These calories are further quantified in order to estimate the TDEE.

Depending on your daily activity level this quantifying number may vary between 1.2 and 2.

TDEE = BMR x 1.2-2

How to choose your quantifying number:

Exercise level Daily Calories Required (Kcal/day)
Little to no exercise Daily calories needed = BMR x 1.2
Light exercise (1–3 days per week) Daily calories needed = BMR x 1.375
Moderate exercise (3–5 days per week) Daily calories needed = BMR x 1.55
Heavy exercise (6–7 days per week) Daily calories needed = BMR x 1.725
Very heavy exercise (twice per day, extra heavy workouts) Daily calories needed = BMR x 1.9

Now let’s use my body to calculate my TDEE: I am 27 yo, 80 kg, 20% BF , 176 cm height, weight train 3 to 5 times a week. I will use the Katch-McArdle Formula to calculate my BMR:

My BMR  = 370 + (21.6 x 64)= 1752.4 calories ≅ 1750 calories

My TDEE = 1750 calories x 1.4 = 2450 calories

OK, now that you know how to calculate your TDEE, you must know that these are the calories that your body needs in order to maintain it’s current weight.

Depending on your goal, you must modify the required calories for maintaining your current weight.

If your goal is to lose weight, you should eat 10-20% less calories than your TDEE. This percentage is chosen so your metabolism does not shut down immediately. It is important to keep a fairly low caloric deficit so your body can slowly progress and adapt to the weight loss process.

If your goal is to gain weight, you should eat 5-10% more calories than your TDEE. By weight gain you actually should aim for muscle gain. Choosing a higher percentage will probably lead to a lot of fat gain additional to the muscle gain.

Let’s continue with my numbers considering my goal is to gain weight:

My daily calories requirement for my goal (gain muscle mass) = TDEE x 10% = 2450 x 10% = 2695 calories.

Now that you know how to calculate your calories according to your goals, it is time to calculate the macronutrients that IIFYM is based on.

There are 4 macronutrients

  1. Protein – 4 calories for each gram of protein
  2. Fat – 9 calories for each gram of fat
  3. Carbohydrate – 4 calories for each gram of carbohydrate
  4. Alcohol – 7 calories for each gram of alcohol

I strongly recommend you to completely remove the alcohol from your nutrition habit. Only consume it on occasions. If you are overweight I suggest you to avoid it completely even on parties until you get close to your goal. Alcohol will most likely make you hungry and you will lose the will power to avoid bad food.

I believe that a healthy lifestyle is a combination between nutrition, exercise and mental health.

Having said this, I cannot stress the importance of practicing any kind of physical activity. It has so many benefits.

The macronutrients are also set up according to your goals.

Below you can see the macro setup for an individual that is having regular physical activities:

Protein: 2 grams of protein for each kilogram of your body

Fat: 20-30% of total daily calories

Carbohydrates: After fixing the daily protein and fat you can find out the carbohydrates by subtracting from the total calories the calories coming from protein and fats and dividing the rest by 4.

I am showing you exactly how to calculate your macronutrients in my article “How to start a body transformation”. Here you can find examples of macros calculation as well as food suggestions for each macronutrient. Also, you can find a simplified version to calculate your total calories for the day.

I strongly suggest you to check out the body transformation article. It’s a nice guide that teaches you how to set up your macros according to your needs whether you want to lose or gain weight.


  • Very easy to stay consistent with IIFYM
  • There is no food restriction
  • Helps achieving your weight goals


  • Does not emphasize the importance of micronutrients
  • Does not take the health conditions into account
  • There is a risk you create bad eating habits due to food choices

Practical recommendations

It is important to be able to adapt as soon as possible to any change in your life.

The sooner something becomes a habit the more chances you have to stick to it.

There are multiple ways to track your macros.

You can create your own data base in an Excel file and just add the food that you eat.


You can download food tracking apps that you can find on the internet.

The applications are very convenient because they make tracking macros very easy. All you have to do is to scan the bar-code from your food and it will tell you exactly each macronutrient.

The most popular apps are: MyFitnessPal, Cronometer, MapMyFitness or MyMacros. You can easily find them on App store or Google play.

After you successfully calculate your macronutrients, make a list with all the foods you enjoy eating and check their macronutrients.

Then try to fit them into your daily macro requirements.

It is important to hit all 3 macronutrients every day and be consistent.

My recommendation is to eat at least 90% of the calories from clean food and max 10% junk food. This way you make sure you get enough vitamins and minerals while still enjoying the cheat meals.

Try IIFYM with Intermittent fasting, it can help you reach your goals very easily. You could actually enjoy eating big hamburgers every day while losing weight.

Self experience

I actually started seeing results on my body when I started with IIFYM.

It was way easier to stay on track, easier to maintain the social life. I was able to go out and enjoy food with friends without feeling guilty for sabotaging my progress.

At the beginning I had quite bad food choices but I managed to establish a healthy relationship with the food. Now I eat mostly healthy foods and rarely eat junk food.

IIFYM helped me enjoy the food while still making progress in the gym.

I created my own macro calculator in an excel file which I synced across all my devices and it was easy to track. I even created my own recipes with custom macronutrients.

I strongly suggest IIFYM. If you are a normal person looking to get into shape (yes, it can be the best shape of your life) while still enjoying going out and enjoying big burgers and pizzas IIFYM is for you.

Combined with intermittent fasting, IIFYM can be a very effective way to lose fat consistently.

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