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If you’ve ever been on social media, chances are you’ve seen #IIFYM posted under a picture of some frisky food porn.

If not, then maybe you’ve heard about it in conversation when the topic of diet is brought up:

“Oh, I’m doing IIFYM!”

But what is it?

IIFYM stands for “If It Fits Your Macros”, and is a popular approach to nutrition in the lifting community.

The idea is simple.

You can eat whatever you want provided it fits into your macronutrient – protein, carb, and fat – totals for the day.

It originated on internet message boards as a response to people worrying whether X food would make them fat/die/etc and is a quick and easy way to highlight the hierarchy of importance with regards to nutrition (calories are KING and no magic or evil foods will change that), but in recent years it’s grown to have a life of its own.

IIFYM is now another pillar in the fitness minimalist pantheon, but here are some problem areas you need to avoid if you’re subscribing to the IIFYM philosophy.

This is not an article to create strawmen over IIFYM, but rather to highlight things that need to be understood and communicated to those looking to stick to the IIFYM philosophy:

Protein Quality Matters

By definition, IIFYM focuses solely on the macronutrient composition of the diet. Because of this, “all macros are created equally.” However, this is simply not true – especially when it comes to protein.

Many lifters take it for granted because they naturally already consume high quality protein sources like whey, but this cannot be assumed for everyone.

Protein quality matters.

To reap the most from your training, there needs to be an emphasis on high quality protein sources. This means protein sources that have a high essential amino acid content – especially Leucine. That can be accomplished easily through animal sources, with the exception of collagen.

Vegans can compensate by mixing sources or consuming higher amounts of protein, but this is too complex a topic for this post.

Timing Makes a Difference

If It Fits Your Macros is concerned with one thing: hitting your macros by the end of the day.

So technically, whether you get them all in with one meal or 6 is of little relative importance.

But this is important and needs to be taken into account when constructing your diet.

Protein

To continue on the protein train of thought above, it has been found that a more even spread of protein throughout the day was more favorable for maximizing muscle protein synthesis than an intake skewed towards an evening meal.

In a recent review, Schoenfeld and Aragon recommended a minimum of 0.4g/kg spread across at least 4 meals.

In another review, the same authors have also recommended that the resistance training bout occur in between two of these meals, with 3-6 hours occurring between them depending on the meal composition. This may be more important the more advanced you get, as shown in this study.

Finally, Trommelen and van Loon recommend that a high quality protein of 40g be consumed prior to sleep to maximize the response from training. This can be in the form of a regular mixed meal or as a casein supplement (a slow digesting protein). I regularly consume Greek Yogurt with nuts and fruit as my final meal for the same reason, as this is also slow digesting.

Meal Spacing

Additionally, meal spacing is an important tool for diet satisfaction and adherence.

In a 2015 meta-analysis over the effects of meal frequency on weight loss and body composition, the authors concluded:

No so fast?

Proponents of intermittent fasting may be a little uneasy.

Personally, I have been doing intermittent fasting for over 7 years and the abundance of testimony of its effectiveness worldwide displays it does work, but whether this works best is a separate issue.

In the first real study looking at IF in a lifting population, there certainly doesn’t appear to be any detriments to this approach with regards to muscle mass and strength, but it should be noted that this was on a Leangains style 16h fast, 8hr feeding window, so what goes on in longer fasts has yet to be determined.

My hunch is that they would be detrimental to progress, especially in more advanced trainees.

Fiber

When we talk about macros, we’re talking about protein, carbs, and fat. Aren’t we forgetting something?

Yes, alcohol. You morons.

But we’re also forgetting something else that we need to take into account in the diet:

Fiber.

This is important for digestive health and helps you stay full, but it can be easy to run low if you only consume processed grain sources and avoid fruits and vegetables.

As a general rule for those with reasonable activity levels, you should aim to get at least 10g of fiber in your diet for every 1000 calories you consume. However, more is not better.

Satiety is Key

Macros are macros, but macros come from foods, and foods can vary wildly even at the same macronutrient composition.

For example, compare 100 calories of white bread to 100 calories of fresh strawberries.

Which one will be more filling?

When you look at your macros plugged into your Nutrition app at the end of the day, the numbers will look the same, but they both tell two very different stories.

If you’re getting shredded or have issues with hunger in general on IIFYM, look at your foods a little more closely. In general:

• Select foods to satisfy your requirements that are lower energy density and have more weight per calorie
• Opt for solids over liquids or liquid-like substances

These will fill you up more and make the diet more satisfying.

Whole Meals Are Important

I once worked with a girl who was doing IIFYM. Her way of going about it pretty much emphasized everything in this article, but the one that took the cake was how she’d split up her macros over the day.

A cookie here.

An apple there.

Following by a small chicken breast an hour later – and only a chicken breast.

It was remarkably interesting to witness. Not surprisingly, she was always hungry.

From a physiological perspective, your body just needs what it needs. So this is no big deal. But with regards to being satisfied after a meal and the practical element of not having to graze, put your food choices into full meals and be mindful and focused during them.

You’ll enjoy them more and get that nice ‘down time’ from your day to day routine and obligations.

In Architect of Aesthetics and for my clients, I use a “Macro Split” diagram that contains several different food choices and encourage them to pick 1 food from each protein, carb, and fat section to form a complete meal.

Micronutrients

Having a diet full of whey and pizza might sound awesome, but it’s going to leave you deficient in important vitamins and minerals if you keep it up.

Macros are important for overall body composition, but micronutrients can’t be ignored for optimal physical function.

In Evidence-Based Recommendations for natural bodybuilding contest preparation: nutrition and supplementation, the authors were quick to highlight that there is an abundance of evidence showing micronutrient deficiencies in dieting physique competitors. However, they also noted that this may be due to exclusion of certain foods, which is often the case in compulsive bodybuilding types.

As a general rule of thumb, 80-90% of your diet should come from whole, varied sources with plenty of fruits and vegetables. This will tend to take care of much of the other points in this article as well.

Depending on personal preferences, food availability, and/or food allergies, supplementation such as a general multivitamin can be a good “insurance policy” for ensuring adequate micronutrient intake, but this needs to be assessed on a case by case basis.

Conclusion

IIFYM is a pretty good way of approaching nutrition through its simplicity and enjoyment for those who choose to subscribe to it.

In a fitness world where obsessively clean eating and rigidity of dieting was the norm, If It Fits Your Macros was a breath of fresh air that allowed people to live their life and focus more on the things that really matter.

However proper education is required and further attention to detail is required if you want to optimize the process and your results, so keep these things in mind as you go around fitting things into your macros.