IIFYM: If It Fits You Macros Explained

Hello Fit Fam!

This approach to nutrition has always baffled me. How can someone justify eating foods that are created in a lab over foods that are natural in genesis? How can someone expect the same fitness results from fast food? How can eating this way possibly make you feel good? And what the heck is IIFYM anyways and how does it work? Well it’s about time I find out!

Today I will be discussing:
1)    The Basics
2)    How It Works
3)    Why I did not adapt this approach to nutrition

1) The Basics

When doing research on IIFYM I found a great 2 part article by DoYouEven.com called If It Fits Your Macros –The Flexible Diet that has formed the basis of my post. If you’d like to learn more about this nutritional approach I highly recommend this website and it’s articles for your own personal research.

So let’s jump right in. IIFYM is based on your Micro and Maco nutrient intake.

What is a micro-nutrient exactly? They are the nutrients your body needs only in small amounts within your diet. These lovely little nutrients include: Vitamins and Minerals, which help your organs grow.

What is a macro-nutrient? They are substances needed in large amounts. These are your Carbohydrates, Proteins and Fats. These are needed for your body’s growth, metabolism and other bodily functions.

IIFYM also takes calories into consideration stating that, “Thermodynamics dictate that a calorie is a calorie regardless of the macro-nutrient composition of the diet.” Pubmed Study – Is a calorie a calorie? *Please note that this study looks at weight loss on a high protein/low carb diet in relation to a low-fat diet not in comparison to a clean diet. Please read the study for more insight if interested.

So what exactly is IIFYM all about!

It is a flexible diet approach where you don’t take into consideration the ingredients but instead focus on your daily calorie, macro-nutrient and micro-nutrient intake in order to achieve your fitness goals. Although this approach to nutrition does consider micro-nutrients important (vitamins and minerals), the emphasis is put largely on your macro-nutrients hence why it is called If It Fits Your Macros. It is believed that, “it’s very much possible to achieve your desired body composition whilst disregarding your micro-nutrient intake.” (DoYouEven.com). But for health reasons it is generally advised you do fill your vitamin and mineral intakes for the day.

IIFYM is for those looking for balance in their diet and don’t want to give up the foods they love! This approach allows freedom so that you are not left feeling guilty when you “cheat” on your diet. Alas you can have your cake and eat it too!

2) How it works

So how can the McDonald’s dollar menu be considered appropriate sustenance! It’s believed that “your body does not recognize whether the food your eating is ‘clean’ or ‘junk’. It will only recognize food’s for it’s nutrients, such as proteins, fats or carbohydrates.”

IIFYM on Calories:

DoYouEven.com provides a great example to consider:

A McDonalds Seared Grand Chicken Burger is worth 501 calories which consists of 35.3g of protein, 15g of fat and 53.4g of carbohydrates.

Whereas, 130g of chicken, 25g of cashews and 120g boiled white rice is worth 520 calories which consists of 16.5g of fat, 55.2g of carbs and 37.9g of protein

When you consume either of these meals, your body processes the food based on the macro-nutrient values (which you can see are extremely similar) and will yield the EXACT same effects on your body’s composition. These results are solely on body composition and do not take into account the micro-nutrients which your body needs in order to maintain your health.

IIFYM on Fat:

You may be thinking, “well what about the different types of fats in these meals”, because I know that was my first thought! Of course the burger will be higher in unhealthy saturated fats, but this doesn’t matter! Says who? Recently in the U.S. a professor of human nutrition decided to lose weight purely through counting calories and disregarding the rest of the nutritional values of the foods he ate. During his 10-week calorie deficit diet he ate “a steady stream of…Hostess and Little Debbie snacks…Doritos chips, sugary cereals and Oreos.” What’s most surprising is his health actually improved! To read the full study please read the following article: “The Twinkie Diet”

IIFYM’s Calculations:

If It Fits Your Macros is truly a science. Your diet is customized to your body and your goals. Alright, it’s time to do a little bit of math.

Step #1 Knowing Your Stats:

You’ll need to know your age, height, weight, gender, and daily activities.

To give you a better understanding we are going to use me as the example:

Age: 21

Height: 5”2

Weight: 113lbs

Gender: Female

Daily activities:

  • Gym x2
  • Work (Desk Job)
  • Commuting

(Wow my life is terribly exciting)

Step #2: Plug Your Stats Into a TDEE Calculator

IIFYM.com has created an incredibly accurate TDEE calculator and you can find it in the link below:

TDEE Calculator

  • TDEE: Total Daily Energy Expenditure; the amount of calories your body burns in a 24 hour period including all exercise, sleeping, walking etc

My results said that I would be able to eat 2284 calories per day if I wanted to maintain my current body weight! (Yippie!)

Step #3 Calculate your Macronutrients

Now that I have the number of calories I’d need to consume in a day just to maintain my weight its time to workout how I want to consume those calories. (Is anyone else getting hungry)

In order to be able to divide your macros accurately you will need to be aware of the values of each macronutrient.

  • Carbohydrates: 4 calories per 1g
  • Fat: 9 calories per 1g
  • Protein: 4 calories per 1g

Okay so lets work out how I would divide my macros. It’s believed that while protein and fat are necessary for a person to function and retain muscle, these macros will be set from the beginning and won’t change. The rest of your calorie allowance will be allotted to carbohydrates.

You should consume 1g of protein per lb of body weight, 25-30% of total calories should be fat and then the rest should be carbs.

Here’s the math based on my body:

  • Protein: 113lbs x 1g of protein = 113g of protein a day / 113g x 4 calories = 452 calories a day
  • Fat: 2284 calories (my TDEE)/ 4 = 571 calories a day
    • 571/9 = 65g of fat a day
    • Total Protein + Fat= 1,023 calories a day
    • Carbohydrates: 2284 -1023= 1261 calories a day
      • 1261 /4= 315g of carbs per day

Therefore me at 113lbs would be eating a TDEE of 2284 calories a day, which would include 113g of protein, 65g of fat and 315g of carbs per day to maintain my current weight. Oh baby!

Step #4: Hit Your Maintenance Macros for 2 Weeks

Now you should try and hit these values for about 2 weeks and gauge whether the calculator was accurate for you. If you find yourself at the same weight after 2 weeks, congrats you’ve found your maintenance level!

If you lost weight: add carbohydrates

If you’ve gained: consume less carbohydrates

Step #5: Adjust Your Macros According to Your Goals

Depending on what your fitness goals are you will either have to add or take away carbohydrates and fats.

Step #6 Enjoy Your Results!

At this point you should be eating cake and celebrating!


3) Why I do not take this approach to nutrition

I do not take this approach for a few reasons:

1)    The constant calculations at every meal

Having recovered from an eating disorder, I know the psychotic chaos that can derive from counting macros. To have to go back to calculating every calorie, and gram of protein, fat and carbs to ensure I was meeting my macronutirents seems a bit obsessive. I have finally arrived at a point in my life where I have a very healthy relationship with food. If I were to calculate each meal based on my goal  (my personal fitness goal is to get down to 15% body fat), I would easily spiral back into a place did rather not be.

2)    The science done on this approach seems like bull

I am a firm believer that the chemicals in our food are in part responsible for the cancer epidemic we are experiencing in today’s society. A diet that allows you to believe that these toxic chemical ingredients are good for you seems absolutely ridiculous. Just because you can lose weight eating Twinkies does not mean it will prolong your health or protect you from life threatening diseases such as cancer or heart disease. I feel like this approach is just feeding into the fast food addiction our world has. Also, the fact that micronutrients are not factored into its calculations seems incredibly odd. Vitamins and minerals have a dramatic effect on the way your body metabolizes macronutrients. A depletion in any essential micronutrient could be disastrous for your health.

Please note: This is my personal belief. There is valid research for all approaches to nutrition, it’s all about finding what’s best for you! If you’d like to learn more about If It Fits Your Macros I highly suggest the following websites:



And be sure to watch BioLanyes Video Log on  “Clean Eating” vs “IIFYM” . He is one of my favourite channels on Youtube to watch. His videologs are incredibly informative and useful!

I hope this article has helped you in some way with your own health and fitness journey. If you have any questions please don’t hesitate to email me: fitobunny@gmail.com. I’d be more than happy to discuss any comments or questions, (or even corrections, cause god knows I’m not perfect) you have.

Stay tuned and stay hungry.