The IIFYM diet, short for “if it fits your macros,” has surged into the spotlight of fitness culture popularity in just the last few years. It’s an interesting development because IIFYM does a complete 180 on every other popular fad diet that’s come and gone in the decades prior. While virtually every fad diet before IIFYM enthusiastically rejected calorie counting and insisted that food type (or some other variable) is what ultimately matters for weight loss, IIFYM fundamentally embraces calorie counting as the only thing that ultimately matters for weight loss and that you can actually eat whatever you want as long as your calorie intake is on point.
IIFYM is often used interchangeably with the phrase “Flexible Dieting,” which similarly prescribes that one doesn’t need to rigidly eat an exclusively “clean food” diet to lose weight, and that it’s conversely entirely possible to liberally enjoy “junk” food and still lose weight.
There are two main purported advantages of IIFYM Flexible Dieting:
- It actually works, because its aligned with the pertinent science.
- The less restrictive a diet is, the more likely it is that you’ll actually do it and stick with it.
IIFYM is now the popular go-to diet in many fitness and bodybuilding niches, but does it actually work for weight loss? Can you have your macro-fitting cake and eat it too? We’re answering this question fully and objectively in this edition of the straightforwardfatloss.com straight dope.
Clickable Table of Contents by Section
- Prologue: My IIFYM Cutting Results – Before and After Pictures
- IIFYM Explained: What Are Macros? And What is This Diet of “Fitting” Them, Exactly?
- So, Does Counting Calories and Macros Actually Work for Weight Loss?
- IIFYM vs “Clean” Eating – Which Diet is Right?
- A Quick Summary of How Setting Up An IIFYM Diet, Counting Macros, and Making a Meal Plan Works
- The Drawbacks of the IIFYM Dieting Approach
- The Upsides of Counting Macros
- So, Do You Have to Count Things to Lose Weight?
- What I like Much Better: If It’s Close Enough to My Macros
- A Brief Note on Fear of Inaccurate Counting
- Concluding Points
Prologue: My IIFYM Cutting Results – Before and After Pictures
IIFYM was my strategy of choice for my initial weight loss campaign, and it worked. The pictorial evidence:
Hopefully that quick self appeal to example convinces you that I know what I’m talking about. Moving on…
IIFYM Explained: What Are Macros? And What is This Diet of “Fitting” Them, Exactly?
“Macro” is shortened slang for the word “macronutrient.” A macronutrient is simply a descriptor for each of the three main nutrient groups that collectively make up one’s total caloric intake: protein, fat, and carbohydrates. This is opposed to the many “micronutrients” we need: various vitamins, minerals, etc.
The IIFYM acronym isn’t so much a diet as it is a general philosophy born literally from the go-to catch phrase “if it fits your macros,” which became a stock reply on various fitness forums when newbies asked, perhaps incessantly, if they could eat this or that and still lose fat on a cut.
If it fits your macros… yes, you can eat some [insert any junk food] and still lose weight.
So that’s where the nomenclature came from, and the above stock response encapsulates the fundamental principle of IIFYM dieting: that calories in vs calories out is the ultimate determiner of weight loss and body composition, not food types.
A corollary to this is that IIFYM was a rebellion of sorts from the longstanding and tired dogma in the bodybuilding community that a proverbial “clean” diet of chicken breast, broccoli, brown rice, plain tuna, etc. was necessary for losing weight. Turns out, people started to insist, that you don’t need a squeaky clean (and miserably bland) diet to get lean and ripped, you just need to make sure that your calorie and macronutrient intake are on point.
And again, the key behind all this is that permitting some junk here and there and staying sane is key for the only thing that ultimately matters: actually doing and sticking with the diet and actually getting results.
So, Does Counting Calories and Macros Actually Work for Weight Loss?
If done correctly, Yes, absolutely.
The big upside of the IIFYM approach is that it fundamentally embraces the now decidedly clear scientific reality of weight loss: Overall calories are indeed what ultimately matters, and food choice matters very little to not all all when calories, macros, and miconutrition remain the same.
Weight loss is ultimately a function of you consuming less calories than you expend over time. With an IIFYM cut, you log your food intake and deliberately hit a caloric target that’s a modest percentage less than your calculated caloric requirement, which guarantees, essentially, that the required caloric deficit for losing weight is indeed present. This is opposed to other “eat by feel” strategies, which though they can work, will always be somewhat a shot in the dark.
Calorie and macro counting, thus, is in fact that only weight loss strategy that’s virtually guaranteed to work. That’s its huge upside. No other dietary strategy, though there are many viable alternatives, can come close to making the same claim.
IIFYM vs “Clean” Eating – Which Diet is Right?
This is arguably the central question of the IIFYM debate, but it’s actually a rather pointless one.
Firstly, the assumption that IIFYM and “clean” eating are mutually exclusive is obviously wrong. All foods have caloric and macronutrient values — you can eat “clean” foods and still fit them to your macros.
Secondly, the concept of “clean” foods in and of itself is ill defined and ultimately meaningless. Ask 100 different gew-roos what’s “clean” or not, and you’ll get 100 different answers. There’s no decidedly clear definition.
Thirdly, there’s the naturalistic fallacy — just because something is decidedly natural doesn’t mean it’s inherently better or healthier.
Fourthly, even if one wanted to be truly natural by literal definition, doing so is essentially impossible anyway since virtually everything we eat, use, or otherwise interact with today is influenced by humankind in some capacity.
The ultimate answer to the question is to use common sense and reject the false dichotomy: Embrace the scientific truth that calories matter, eat *mostly* nutritious whole foods, but stay sane by enjoying *some* treats in reasonable moderation.
A Quick Summary of How Setting Up An IIFYM Diet, Counting Macros, and Making a Meal Plan Works
The process is pretty straightforward. Just use one of many available online calculators (I currently like this one) to figure out your calorie and macro targets:
Then, you use a food diary (Cronometer is my favorite) to actually log what you eat, the goal being to hit your calculated daily calorie and macro targets:
You can try and hit your calorie and macro targets on the fly, but most people realize that using a preset meal plan is much easier. For example, you decide in advance what you’re going to eat each day of the week, you plan it out so you’ll hit your macros, then you simply follow the plan.
It can be a little bit boring and repetitive, I’ll admit to that, but the trade off for decision fatigue removal and the virtual guarantee that your diet will work makes it totally worth it for many people.
* Further Reading:
- A full guide on how to actually calculate your macros for fat loss (cutting)
- A full guide on how to actually make an IIFYM diet meal plan
The Drawbacks of the IIFYM Dieting Approach
Firstly, and very obviously, most people will get the heebie-jeebies if you say the phrase “count calories” or “measure your food with a kitchen scale.” Though many people learn that counting calories can actually be quite a lot easier than you’d think — and it does take a little practice — the simple fact is that most people just won’t consider counting calories, ever. If those people want to lose weight, they’ll need a different viable strategy.
Secondly, no matter how much you dial it in, counting macros is a sufferable chore at best. The trade off of virtually guaranteed efficacy is some extra work. Maybe that’s a worthwhile trade for you, or maybe not.
Thirdly, IIFYM can enable poor eating habits:
- It’s tempting to defer to packaged junk food with detailed serving and nutrition facts because it’s easier to track and log.
- Many dieters, after perhaps years of begrudingly eating a “clean” and restrictive diet, get very excited that they can actually enjoy their vices and end up overdoing the junk while chanting “fits my macros!”
- There’s a risk of social friction and personal stress if you don’t know how to factor in normal and recurring affairs like restaurant meals or holiday parties. (And yes, by the way, you absolutely can enjoy such things and still be IIFYM compliant, which we’ll get to.)
Fourthly, it’s possible to unnecessarily pigeonhole yourself into hitting an ostensibly perfect macronutrient ratio. A lot of people get hung up on a golden combination to maximally expedite fat loss, but the truth is that there is none. Macro ratios matter very secondarily to overall calorie intake.
The Upsides of Counting Macros
The first big pro, said again, is that IIFYM takes the shot-in-the-dark guesswork out of dieting and, if done right, makes weight loss virtually guaranteed. For many, that’s a worthwhile trade for the extra work.
Expounding on that, secondarily, is that IIFYM removes decision fatigue. You adhere to the plan and that’s it. You don’t really have to think. That’s actually a major and underrated relief, as compared with your average dieter who’s constantly questioning, day in and day out, if they can eat this or that.
Thirdly, IIFYM is a great learning experience. Most people have absolutely zero idea of what’s actually going into their body — weight loss saboteurs are often insidiously calorie dense snacks hidden under the guise of a “health” food label. Most people who count calories for the first time have a real wake up call. Counting macros will give you a clear picture of what’s actually going on, much like keeping a budget will finally give a perpetually broke compulsive spender a clear picture of what’s actually going on.
Fourthly, as extension of the third point, learning how to do IIFYM and actually successfully losing weight with the strategy will make maintaining your results with “intuitive” eating by feel much, much easier to do, because you actually get solid experience for what the “right” food intake should be. Most people won’t count calories forever, and subsequently managing your weight with “intuitive eating” becomes so much easier with the experience of actual calorie counting to draw on.
So, Do You Have to Count Things to Lose Weight?
No, it’s not *absolutely* required.
There are literally tens of thousands of online success stories from, say, people who did a paleo diet or vegan diet or a ketogenic low carb diet and didn’t count a thing.
A weight loss causing caloric deficit doesn’t require your accounting of it to exist. If you count things up and definitively establish it, sure, you’ll lose weight. Or, if you make sensible food choices and inadvertently establish it, you’ll lose weight too.
The way I see it, it’s ultimately a matter of preference. Would you prefer to:
- Eat by feel, and accept that your fat loss will be a somewhat loosey-goosey shot in the dark? Or…
- Tolerate the little extra work of counting in exchange for the peace of mind that the required deficit is certainly present?
There’s no right answer – ultimately what matters is that you pick any viable strategy that you’ll *actually do* consistently enough to conduce actual results.
What I like Much Better: If It’s Close Enough to My Macros
The question of counting vs not counting is not binary. What I mean is, you can vastly simplify the IIFYM process if you’re willing to accept a small margin of error, which is totally permissible — a little inaccuracy won’t impact successful long run weight loss.
Think of it this way: Long run weight loss success is like long run stock market success. The short term variance doesn’t matter, it’s the long run trend that does.
You do not have to track your calories and macros with the due diligence of an IRS auditor. If it’s close enough, the variance will zero out over the long run:
- Those slices of cheese will average out to be 100 calories, so I’ll just log that
- Those fist sized chicken breasts will average out to be 8oz, so I’ll just log that
- An egg is 80 calories, on average, so I’ll just log that.
Sure, your egg today might be 87 calories, but the one tomorrow might be 73 calories, so it evens out. See what mean? Here’s a picture to convey the idea:
It will take some practice, but once you start gauging your running progress and getting a feel for a dialed in system that works, you’ll start to see simple shortcuts you can take that makes life a lot easier:
- That golf ball blob of guacamole is usually around 30g, so I’ll just assume it’s that from now on and not bother weighing it.
- I don’t care about the cream in my coffee, I’ll just lower my caloric target by 40 and negate it.
- I know what a 5g slab of butter I fry my eggs in looks like, I won’t bother weighing it off.
- I’ll just follow some basic guidelines for my weekly restaurant dinner and call it 1000 calories.
This becomes especially easy if you have a rotating meal plan, because you get so familiar with the foods you eat that it basically goes on autopilot. During the final phase of my cut you saw above, I rarely spent more than 5 minutes a day tracking and logging my food — it really can be that easy, actually.
A Brief Note on Fear of Inaccurate Counting
The biggest hang up for newbie IIFYM-ers is a fear of inaccuracy. Is my calorie target right? Am I logging my food right? etc., etc.
The answer to all those kinds of questions is that it doesn’t matter.
What does matter is that you’re consistent with whatever it is that you do. Pick a baseline, and stick to it. Then, here’s the key: You gauge your progress periodically, see if it’s working or not, then adjust accordingly. Rinse and repeat until it’s working as intended.
If you’re consistent, you can make quantitatively meaningful adjustments to your system until it’s working, and any initial accuracy will inevitably become inconsequential.
* Further Reading:
- An IIFYM (if it fits your macros) diet, in contrast to most other fad diets to date, has daily calorie and macronutrient (protein/fat/carb) targets which you can hit with whatever foods you like.
- Not only does IIFYM work for losing weight, it’s the only diet that’s virtually guaranteed to work because it establishes with certainty the ultimate determiner of weight loss: a calorie deficit.
- “Clean” eating and IIFYM are not diametrically opposed. You can fit “clean” foods to your macros and mix in some occasional junk to stay sane, which is the whole point of why IIFYM came into existence to begin with.
- IIFYM has some downsides. It’s tolerable extra work at best, it might enable poor food choices, and it might cause stressful friction with social eating if you don’t have a plan for how you’ll handle those situations.
- Counting macros is not an absolute requirement for lose weight. Whether or not you should is ultimately a matter of preference: Do you prefer certainty and peace of mind? Or, would you rather do less work and accept some uncertainty?
- However, learning how to count macros at least once in your life will make subsequent “eating by feel” from then on much easier to do.
- You can greatly simplify the system by doing “if it’s *close enough* to my macros” instead. A small margin of error is not at all unconducive to effective long run weight loss. Though it took a little practice, my simple “close enough” methodology only took 5 minutes a day of work.
- The ultimate key to any diet’s success is being consistent and making meaningful adjustments as you go. The initial accuracy of your system doesn’t matter all that much. What does matter is that you can gague your progress and tweak things as you go until you hit the sweet spot of ultimate progress.