The ultimate guide to IIFYM (“If It Fits Your Macros”)

The ultimate guide to IIFYM ("If It Fits Your Macros")
The ultimate guide to IIFYM ("If It Fits Your Macros")

In this article we delve deep into the subject of the ancient debate about “clean” and “dirty” food – and what is really true from a physiological point of view. Then we will explain what IIFYM is, what the disadvantages are, how to avoid them, what the benefits are, and finally how to create your own IIFYM diet plan.

The natural differences of food

"If It Fits Your Macros" (IIFYM)
“If It Fits Your Macros” (IIFYM)

I’m generally not a fan of assigning arbitrary “percentage importance” to certain elements of a fitness plan (such as “nutrition accounts for 90% of success, training for 10%”). Let’s just agree here that nutrition is a big piece of cake.

However, now that we have this large piece of cake on our plate, we have to look at another question: How large is the “healthy” portion and how large is “unhealthy” portion of the piece?

Admittedly, this metaphor is quite tricky in the scene, but I don’t want to start over and ask for your understanding. Let’s hypothetically say we cut ourselves a nice big piece of pecan pie. You might think,”Hey, pecans contain a lot of healthy (read: clean) essential fatty acids, so I’ll just eat this part of the cake.” But not so fast, you little nut lover. What about the bliss that holds the cake together? All the butter and brown sugar that melts in your mouth every time you take a bite?

And what about the soil, which consists of Graham crackers and forms the basis of (almost) every pecan cake? Does this part of the cake now count as a “healthy” or “unhealthy” part?

The relevance of the expression “healthy

Well, there are no simple yes or no answers to these questions, because the term “healthy” refers to your own specific nutritional needs. People toss the word “healthy” around arbitrarily in certain predefined situations, but the reality is that for one individual it may be something completely different from someone else’s health. In the Darwinian/biological sense, something “healthy” only has to meet the requirement to promote the survival/fitness of the organism.

Not to mention that the absurd amounts of performance-enhancing substances consumed by many athletes are only hiding the problem; the sad truth is that bodybuilding has increasingly become a sport/lifestyle that unconsciously represents an ideology of health sacrifice to the general public for a certain appearance. But I digress…

Why extreme diets are bad (long-term)

Due to their rigid requirements and imbalance, diets that impracticably prescribe and/or severely restrict certain macro-nutrients are, in most cases, unsustainable – i. e. successful over long periods of time – in most cases.

On the other hand, adherence (observance of the guidelines) to a more practicable diet is probably higher. It seems to have gone completely by the so-called “fitness gurus” when these other unusual (extreme) dietary approaches invent that these – no matter how good they sound on paper – will not work, as long as they are not practicable for a large number of people and do not provide any room for manoeuvre; we are human beings, not machines.

As already mentioned, bodybuilding promotes extreme lifestyles, which is indeed the reason why this whole dichotomy was created in terms of “clean” and “dirty” food.

People (especially bodybuilders) see certain foods and think,”Rice, chicken and broccoli are clean, so I’ll just stick to it and eliminate everything else.”

What makes a food “healthy” or “unhealthy”?

Let’s take a step back and think logically. For example, what does a bone- and skin-free piece of chicken breast “clean” (healthy)?

Is it the macro-nutrient profile because it is almost exclusively made up of protein (I should rather say “bread protein”)?
What about the micronutrient profile? Maybe it’s “clean” because of the keeping of the animals that roam freely around the farm before they were allowed to meet the butcher?
Just like the question of “cleaner” food, we also have to ask ourselves how to categorize/define “junk food”. I’m sure many readers automatically think of things like pizza, burgers or ice cream when they hear these words. But why? Is it because these foods are industrially processed? Because they are rich in fat or sugar, or are they packed into this category because of their micronutrient content?

These are many questions at once, but don’t worry – answers are given to

“If It Fits Your Macros” (IIFYM)

In recent years If It Fits Your Macros (IIFYM) has developed into an increasingly popular nutritional ideology in bodybuilding subculture. This movement has never really made sense to me, because IIFYM is nothing really new or profound. In fact, IIFYM is the way pretty much everyone who has ever been tracking their food supply has always eaten, with the exception that there are no “forbidden” foods. Of course, the idea that you can eat anything you want has enraged the “clean-food” advocates and has led them to condemn IIFYM as an inferior and illogical dietary approach.

This may open the eyes of some readers. Especially when he has bowed to the good old chicken, rice and broccoli in the last decades. However, the reality is that very few foods/ingredients are fundamentally unhealthy and harm the body composition.

Specific food allergies (everyone nowadays seems to be suddenly an undiagnosed case of celiac disease) and irrational fears of certain food additives (such as monosodium glutamate) excepted, there is almost no basis for describing a food generally as “dirty” or unhealthy.

The dose makes the poison

Don’t get me wrong: There is enough research to show the harmful effects of some artificial ingredients and other food supplements. My point, however, is that if you don’t consume these things day in and day out in horrendous amounts, you don’t have to worry.

Two good examples I can think of are hydrogenated oils and corn syrup; both ingredients have an incredibly bad reputation, especially because of the concomitant frequent use in food production and the increasing overweight rates.

Yes, it has been proven that transfatty acids, which are produced by the partial hydrogenation of fats, can also promote heart disease in small amounts. However, if you take less than 1 gram of trans fats per day (which is not particularly difficult if you do not plan to inhale dozens of donuts), the health consequences are negligible.

And corn syrup is simply another case in which it is a matter of limiting consumption. If you follow an otherwise healthy and calorie-controlled diet, a little corn syrup will not be the deciding factor for body composition and health.

Unfortunately, the preaching of moderation to an audience of extreme bodybuilders, health freaks and fitness enthusiasts is usually not well received, but this is a good overhang to the next section on the shortcomings of the IIFYM approach and how to correct them.

Logical Diet 101: Avoiding deficits and excesses

Logical Diet 101: Avoiding deficits and excesses
Logical Diet 101: Avoiding deficits and excesses

In the introduction of this article, we have already mentioned what makes a nutrition/food healthy (and that there is no generally correct algorithm that can spit out the precise needs of a nutrient). From this it can be concluded that one has to take the time to get to know the needs of one’s own metabolism – which probably only works through trial and error. The most important thing to keep in mind, however, is that a healthy diet that guarantees optimal performance should avoid extremely high intake and nutritional deficiencies. It should also cover the daily calorie requirement.

The food you ultimately choose to meet these requirements is ultimately only a means to an end – and this is the very core of IIFYM.

A big disadvantage of IIFYM, however, is that some people use it as an excuse to ignore things like macronutrients, fiber, the quality of protein sources, essential fatty acids and sugar consumption.

For example, a diet containing tons of soy protein would not be nearly as effective as a diet containing high quality, leucin-rich protein sources (such as whey and eggs) to build muscle and reduce fat.

What IIFYM really is

For some strange reason, many people who have read about IIFYM think it’s a form of nutrition that gives you the freedom to eat pop-tarts and cookies to meet your carbohydrate and fat needs. If you’re not a genetic anomaly, excessive amounts of monosaccharides, minimal amounts of fiber and a lot of trans fatty acids won’t fit into your macronutrient defaults – especially if you want to stay in shape and healthy.

In addition, IIFYM should be renamed into the (admittedly not quite so attractive) name “IIFYM/µ”. To return to the pop-tart example: Good luck covering your micronutrient needs with a wagonload of donut and some protein shakes (for the “bread protein”).

If you try halfway to achieve decent micro- and macro-nutrient intake, you will most likely end up consuming lean animal protein sources, dairy products, nuts/seeds, wholemeal carbohydrates, vegetables and fruit. I refuse to call these foods “clean” because this expression is arbitrary and pointless; rather, these foods should simply be called “nutrient-dense” (I run the risk of provoking semantic arguments).

Finding a healthy balance

Does this mean that your diet must consist exclusively of these nutrient-dense foods?

Certainly not, and this is exactly the advantage of IIFYM – namely that it allows for balance and flexibility. Someone who wants to integrate more nutrient-poor foods with “empty calories” into their diet can do so – provided they still meet their nutrient requirements at the end of the day (and provided that the macronutrient distribution for each meal is balanced).

It may take some time to get used to this concept, but you are mistaken if you seriously think that a piece of pizza or some ice cream would sabotage your own efforts in training.

The irony of the matter is that many people who hold so tightly to the idea of “clean eating”, after a short period of time, completely break into it and fall for the eating spells and cheat days. Don’t make this mistake, because these binge episodes can and will quickly have visible consequences for your body composition.

A typical “clean” diet vs. a IIFYM diet plan

Logical Diet 101: Avoiding deficits and excesses
Logical Diet 101: Avoiding deficits and excesses

Check out one of the mainstream bodybuilding magazines and you’ll find the same stuff over and over again that makes up the diet of almost every fitness head.

A typical “cleaner” nutrition plan

Let’s take a look at an example of such a “clean” diet:

  • Meal 1: 6 Eiklars, 80 grams oatmeal, 30 grams almonds
  • Meal 2 (pre-workout): 1 Scoop Whey Protein mixed with 40 grams of oatmeal and a teaspoonful of hempseed oil.
  • Meal 3 (post-workout): 2 scoops of whey protein mixed with 50 grams of a simple carbohydrate source (e. g. corn starch or dextrose)
  • Meal 4:170 grams grilled chicken breast, 1 cup brown rice, 2 cups steamed broccoli
  • Meal 5:1 Scoop Whey Protein mixed with 40 grams of oatmeal and one teaspoon of hempseed oil.
  • Meal 6:1 Scoop Casein Protein, 30 grams of mixed nuts, 2 cups of steamed asparagus

The macronutrients of the day: 235g protein/215g carbohydrate/80g fat. Approx. 2520 kcal.

What a monotonous, boring diet! Such a diet often leads to a complete loss of the joy that one should normally have in eating. It’s sad that so many people would see such a diet plan and congratulate the individual on how “healthy” he/she is eating, even though this kind of nutrition is actually far from it (well, at least among Bro’s and “hardcore” athletes).

An exemplary IIFYM diet plan

Let’s have a look at an IIFYM diet plan that has exactly the same macro nutrient distribution as the example above:

  • Meal 1: 2 cups (approx. 454g) of greasy Greek yoghurt with half a cup of blueberries and 1 cup of cheerios, an omelette of 3 eggs with vegetables and salsa.
  • Meal 2 (lunch at Chick-fil-A): 1 chicken sandwich, 8 chicken nuggets, 1 small bowl of fruit, 1 can of sugar-free soft drinks.
  • Meal 3 (post-workout): 1 cup of low-fat cottage cheese mixed with 1 scoop of whey protein and 30 grams of mixed nuts, 2 low-fat vanilla ice cream sandwiches.
  • Meal 4:1 cup of cooked spaghetti with half a cup of marinara sauce and 340 grams of 7% fat minced beef

The macronutrients of the day: 235g protein/215g carbohydrate/80g fat. Approx. 2520 kcal.

Now tell me, which of these two nutrition plans would you prefer to use? I estimate that 99% of readers would prefer the IIFYM plan to the usual “clean” plan.

Pay attention to the flexibility of the IIFYM plan, which allows the individual to eat out and enjoy a few treats here and there.

How to create your own IIFYM plan

How to create your own IIFYM plan
How to create your own IIFYM plan

A pragmatic way to calculate your energy needs is to use the Harris Benedict formula, including the daily activity level.

For most strength trainers, a protein intake of about 1.6 – 2 grams per kilogram of lean body mass is recommended. Once protein requirements have been determined, the next step is carbohydrate requirements (which are highly dependent on individual insulin sensitivity).

Finally, once protein and carbohydrates have been established, the rest of your calories are replenished with fats.

Sample calculation

Here is an example of what this would look like for a trainee with 80 kg of lean body mass and a calorie requirement of 2,750 kcal.

  • Calculate the calorie requirement: Harris Benedict formula combined with an activity formula.
  • Set the protein intake to 2g/kg lean body mass: 160g protein per day.
  • This individual is highly insulin-sensitive, so we put the carbohydrates on 4g/kg lean body mass: 320g carbohydrates per day (approx. 10-15% dietary fibre).
  • Since carbohydrates and protein each contain an energy of 4 kcal per gram, we are at (320+160) x 4 = 1920 kcal. This leaves us with 830 kcal for the fats, which corresponds to about 92g, since fats have 9 kcal per gram (830/9=~92). Of these, 20-25% should be saturated fatty acids.
    The rule of thumb here is that for a fat loss a calorie deficit of about 10-20% per day should be aimed at (whereas this should come from a reduced carbohydrate intake as soon as the fat intake reaches the lower limit of 0.5g/kg body weight).

If you want to build muscle mass, you should aim for a calorie surplus of ~+10%. These are, of course, very generally formulated blanket statements that have to be adapted to the individual.

Macro-nutrient balance: Do’s and don’ ts

A final criticism of IIFYM would be that it does not address macro nutrient distributions within meals. Okay, most fitness enthusiasts probably already know that they should consume a certain amount of a complete protein source (like most animal protein sources) with every meal to fully exploit protein biosynthesis.

Yes, the calories ultimately determine whether and how much weight we gain or lose, but a way of eating with a screwed-up macronutrient intake will undoubtedly result in certain undesirable physiological effects.

In order to illustrate this with an example, we have developed two isocaloric nutritional plans which have identical macro-nutrient distributions (approx. 2,500 kcal, consisting of 150g protein, 300g carbohydrates and 75-80g fat), but distribute them very differently throughout the day.

Nutritional plan #1

Balanced intake with more carbohydrates around the workout window

  • Meal 1:600kcal / 40g protein / 50g carbohydrates / 15g fat
  • Meal 2:450kcal / 30g protein / 50g carbohydrates / 15g fat
  • Meal 3:390kcal / 20g protein / 80g carbohydrates / 10g fat (pre-workout meal)
  • Meal 4:575kcal / 30g protein / 80g carbohydrates / 15g fat (post-workout meal)
  • Meal 5:505kcal / 30g protein / 40g carbohydrates / 25g fat

Nutrition plan #2

Unbalanced supply

  • Meal 1:665kcal / 5gr protein /150g carbohydrates / 5g fat
  • Meal 2:465kcal / 5g protein / 100g carbohydrates / 5g fat
  • Meal 3:660kcal / 5g protein / 25g carbohydrates / 60g fat (pre-workout meal)
  • Meal 4:225kcal / 25g protein / 20g carbohydrates / 5g fat (post-workout meal)
  • Meal 5:505kcal / 110g protein / 5g carbohydrates / 5g fat

The calories per meal are actually quite similar between the two plans, but you can clearly see how messed up the distribution of macronutrients per meal is in the second diet plan.

During the first 3 meals many carbohydrates are consumed, but protein and fat are neglected. It doesn’t make much sense to fill up with carbohydrates at this early stage in order to recharge with fat before training. And the last meal of the day simply contains an excessive amount of protein. I’m sure that anyone with a little knowledge of performance-oriented nutrition would not plan their macronutrient intake according to the scheme of the second plan.

Yes, with an IF-oriented diet, one takes large amounts of calories and macronutrients in short periods of time. However, there is usually more than enough protein in this case. When it is important to activate protein synthesis as often as possible during the day (for muscle building) and to eat several meals a day, it makes the most sense to divide up the protein supply evenly instead of feeding too little in some meals and too much in others.

This comparison should simply illustrate the point that IIFYM can be misinterpreted in the sense that the macro nutrient distribution over the day is irrelevant in order to improve body composition. It may not play a major role, but here too, there are strategic considerations that flow into it.

Extreme diets don’t make you hardcore

One thing that has always astonished me is why many bodybuilders think that a monotonous, simple and ultra “clean” diet is superior to one that is varied and tasty when it comes to improving performance and body composition.

The idea that eating chicken breast, brown rice and asparagus is a blatant type must disappear. Believe it or not, eating desert dry, tasteless chicken breasts doesn’t make you any more crass than anyone else… it makes you a retarded stubborn chick who doesn’t know his way around the kitchen (which is super ironic considering that most bodybuilders spend 50% of their lives in the kitchen).

If you long to feel like you’ve achieved something because you’ve been hardcore, find out how to integrate foods into your diet that you’d really like to eat. This would be a sign to someone who has his or her life under control and a good relationship to his or her diet.

Be creative and considerate with your food choices

There are infinite variations of a healthy, nutrient-dense diet that enhances appearance and performance while at the same time being tasty. Don’t fall for the idiotic idea that you have to sacrifice taste and the psychological pleasure of eating in order to achieve your dream body.

The IIFYM concept teaches us that it’s no problem to add a piece of cake to your diet if you can include a little creativity and self-control in your day. If you want to enjoy a few spoons of Ben and Jerry’s with your children or take your better half out for dinner, plan ahead and incorporate it into your diet.

If you decide to think that depriving yourself of these things makes you more blatant or more likely to achieve your goals as a bodybuilder, then congratulations, the mainstream media and fitness magazines have been successfully washing your brain over the past few years. At this point there really is no other expression for your way of thinking as pure stubbornness.


Written by Marcus

Fitness is not always easy and there is no perfect plan for everyone to stay fit for life. That is why I have set myself the goal of finding the most accessible way for people to build healthy lifestyles.