IIFYM: IdealFit’s Guide to ‘If It Fits Your Macros’

IIFYM: IdealFit’s Guide to ‘If It Fits Your Macros’

IIFYM (If It Fits Your Macros, for anyone not familiar) focuses on a flexible approach to dieting and is a popular option for many women in the fitness world. It has become a huge trend for 2018 and we want to tell you everything you need to know when it comes to IIFYM.

What does IIFYM mean?

iifym women stacking fruit idealfit

Other than knowing it quite literally means ‘if it fits your macros’, there are a lot of women who might not understand the concept. Let’s break this down:

What are macros?

Short for macronutrients, macros refer to:

  • Proteins
  • Fats
  • Carbohydrates
  • Alcohol is often considered a fourth, but for this article, we will mainly focus on the first 3.

Macros also help you determine calorie content in foods. Proteins and carbohydrates have 4 calories per gram and fats have 9 calories per gram.

So let’s say a food label has 5 grams of protein, 4 grams of carbs and 2 grams of fat. You would be looking at:

5g protein (x 4 calories) + 4g carbs (x4 calories) + 2g fat (x 9 calories) =

20 + 16 +18 = 54 calories. 

What do we mean by IIFYM?

In short, IIFYM refers to macro-counting to stay on track towards your fitness and health goals. Quite literally, it involves monitoring your protein, fat and carbohydrate intake on a daily basis to ensure you are eating the correct amount of each. The ‘correct’ amount of each is, of course, subject to individuals’ specific goals and therefore the concept of it ‘fitting YOUR macros’ comes in to play.

Calories in versus calories out

IIFYM works on the theory of calories in against calories out and therefore allows for flexible dieting. It doesn’t cut out any food groups, or any certain food whatsoever. Yep, pizza, crisps and chocolate are all allowed, and, for some people, this can be confusing. However, because of the macro-balance that this ‘diet’ calls for, sadly you can’t eat 1600 calories of Cadbury’s Dairy Milk chocolate every day. It promotes balance and encourages you to watch how much of certain foods you eat.  It does, therefore, require quite a lot of commitment and time to ensure you are monitoring everything you are eating on a daily basis.

iifym women deadlifting idealfit

How do I work out my macros?

As previously mentioned, your macros will depend on your goal and how much exercise you do per week. Most people turned to macros to lose fat or lean down and to help, there are a number of equations you can do to work out how much you should be eating.

iifym calculating macros idealfit

Firstly, calculate your calories.

Your BMR (Basal Metabolic Rate) is how many calories your body would burn if you were asleep/sedentary all day. To calculate this, for women, you can use the following formula:

10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161 = BMR

Now, take your BMR and factor in your exercise and multiply by the following:

1.2 for little or no exercise

1.4 for exercise a couple of times per week

1.5 to 1.7 for exercise several times per week

1.9+ for exercise every day or have a very physically demanding job

We’ve linked to two effective IIFYM calculators at the bottom of this article.

Now, calculate your macros.

However, as a general rule of thumb here are some tips for calculating your macros for flexible dieting.

  • Protein: A good figure to aim for is between 1.5-2.0g per kg of body weight.  For example, if you weigh 65kg then aim for max 130g protein per day.
  • Fat: People often see the word and immediately think the less they eat the better. Healthy fats are vital to a healthy diet and can actually be a huge factor when it comes to losing weight. Aim for somewhere between 0.7g – 1.2g of fat per kg of body weight depending on preference.E.g say we choose to eat 0.9g fat per kg of body weight and use the same 65kg bodyweight example, then your fat intake would be 58.5g per day.
  • Carbohydrates: These can be calculated by working out the calories already assigned to protein and fat per day. 4 calories per every protein gram and 9 calories for every fat gram. Then use the remaining calories from your BMR (calculated previously), divide this by 4 and this will give you your carbohydrate intake.

This definitely is a complicated system, however, if you don’t like using online calculators to tell you what you should be eating, it’s the most effective.

So IIFYM really is just a flexible way of dieting that, although does take some commitment and time, provides effective results for both weight loss and fitness goals. Still not sure what diet plan is best for you? Take a read of our ‘Clean Eating Vs Macro Counting’ article for more inspiration.


Clean Eating Vs Macro Counting: What Works Best?

2017-10-11 16:20:18By Eryn Barber

There are so many online calculators you can use to work out your macros, and we like this calorie calculator from as well as this one from

Sophie Seddon

Sophie Seddon

Lifestyle Editor

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