The Best Thing You Should Learn From Flexible Dieting (IIFYM)


Regardless of the name of the diet you’re on, most of the principals remain the same – Eat this and stay away from that. Almost all of them ask you to cut out the ‘bad’ foods – chocolate, candy, bagels, and the like – and still to good things like grilled chicken and lots of veggies. But what if I told you that there’s a diet out there – a fairly popular one at that – that claims you can eat all of your favorite foods and still lose weight?

That’s exactly what The Flexible Diet does. Also known as IIFYM (if it fits your macros), The Flexible Diet is taking the world by storm. Truth be told I’m not surprised. After all, anyone would love to jump on board with a ‘diet’ that gives you the opportunity to eat all of your favourite foods any time you’d like, right? In this article, we’re going to talk about what flexible dieting is all about, the pros and cons of being on such an eating plan, and more importantly, one extremely important thing we can all learn from it.

Flexible Dieting (IIFYM)

What Is It?

Macro NutrientsThough it’s unclear who actually ‘invented’ the eating plan, the most commonly accepted story is that it was put together by a few different bodybuilders that were sick and tired of the traditionally accepted bodybuilding clean foods – Things like steamed fish, rice, eggs, etc..

They wanted to be able to consume the foods they loved and craved (the one’s we’re told to steer clear of like donuts, French fries, burgers, etc.) without compromising their physiques. And so IIFYM was born.

The theory here is that your body doesn’t know whether you’re eating a greasy burger from your favourite fast food joint or a piece of boiled chicken with a salad. It only knows what macronutrients – That’s fat, carbohydrates, and protein mainly – it’s getting. Therefore as long as you know which macros your body needs to maintain its composition, you can effectively lose/gain weight as you need to, all the while eating whatever you want.

Instead of calorie counting (which a lot of diets have you doing), IIFYM has you tracing your macros to get to your ideal intake. There’s a little bit of math involved, but it looks a lot more complicated than it really is and once you’ve been doing it for a while it apparently becomes second nature. Besides, there’s an app for that (which we’ll talk more about shortly)! Here’s what the rundown looks like:

  • 1 gram of protein = 4 calories
  • 1 gram of carbohydrates = 4 calories
  • 1 gram of fat = 9 calories

So instead of aiming for, say, 2000 calories a day, you’d want to consume 150g of protein, 170g of carbs, and 80g of fat in order to reach those 2000 calories (depending on your needs, the carb and fat goals can fluctuate as you need). As you begin to hit the dreaded ‘plateau’ that comes along with dieting, you simply readjust your macros to fit your new needs. Either way, protein will account for .825g/lb of bodyweight, fats are 25% of your daily energy expenditure (which you’ll determine when you do the initial calculation), and carb intake makes up the remainder.

Here’s an example to show you what I mean: Regardless of whether you’re eating a grilled chicken sandwich from McDonalds or a dish of brown rice and tuna, you’re getting 25g of protein, 33g of carbs and 15g of fat.

What You’ll Need

A Food Scale

Food scaleBecause you need to track absolutely everything you’re putting in your mouth, it’s important to know the exact weight of your foods (regardless of whether they’re raw or cooked).

There are a ton of different food scales out there, but the one I have is very similar to this one. It has a +/- accuracy of 1 gram, a glass platform that allows you to still see the display, and has the ability to weigh up to 22 lbs (which you’re almost never going to need).

Math Skills

In order to calculate your macros, there’s a mathematical solution involved. There are actually various methods (at least according to various bodybuilding websites) of figuring out what your ‘ideal’ macronutrient intake should be, but luckily I found a calculator that can help you figure out a guideline. It’s probably not going to come up with your perfect number, but at least it will give you a decent jumping off point that can be tweaked to your individual needs as you get more comfortable with the program.

An App

MyFitnessPalYou could spend a whole bunch of time creating and keeping a food journal and doing everything yourself, or you could take a whole lot of work out of it by downloading an app that does a whole lot of the work for you.

There are a ton of them out there, but MyFitnessPal seems to be the one that IIFYM enthusiasts prefer because it has the world’s largest nutritional database (meaning that no matter what it is you’re eating there’s a good chance that you’ll be able to find it on there) and it’s available on all platforms (meaning that you can choose to use the website or download it on your phone and use it there).

It might take a couple of days to get used to how the whole thing works, but after the initial phase it’s just a couple of clicks and you’re done.

Spare Time

Weighing food, tracking intakes, and figuring out what the macros in all the food you’re consuming are isn’t going to just happen. It’s going to take time. Sure, you could absolutely just guess, but unless you really know what you’re doing there’s no point. If you don’t have the time to commit to these things (even though it’s not going to eat up a whole bunch once you’re used to it), this probably isn’t the eating plan for you.

Optional: A Book To Help You Out

Of course, there are tons of resources available on the internet that you can browse through that will give you a general idea of how the whole thing works, and there are even a few that break it down in an easier to understand way. Some folks just prefer to have a tangible book that they can refer to whenever they’re starting to feel overwhelmed. If you’re one of those people, here’s a box set that should get you off to a good start – It comes with a book that breaks down how the ‘diet’ works in greater detail and a recipe book with 160 high protein recipes (protein is a huge focus here).

Get the Flexible Dieting IIFYM Box Set #1 Flexible Dieting 101 + The Flexible Dieting Cookbook

Pros & Cons


  • You can essentially eat whatever you want.
  • Once you get the hang of how the whole thing works, it’s fairly simple to maintain.
  • There are a ton of resources available to help you out if you’re feeling overwhelmed or stuck.
  • There’s no calorie counting.
  • There’s no strict fitness plan involved (but remember, physical activity is almost never a bad thing).
  • The IIFYM community seems to be super supportive.


  • There’s not a whole lot of focus on micronutrients (like fiber), which are also important (if you’re going to follow this plan, you should also aim to get approximately 14g of fiber per 1000 calories).
  • Processed food is always going to be full of all kinds of crap that will never be good for you. Just because you’re not gaining weight, doesn’t mean you’re healthy.
  • The math and tracking can be difficult and time consuming.
  • Unless you’re self-disciplined, it can be very easy to overeat.
  • There’s not really a whole lot of focus on activity with this one (I know it falls into both categories, but remember – A sedentary lifestyle kills more people than obesity, HIV, or smoking does).
  • There’s no focus on food quality. Obviously grocery store broccoli is better than none at all, but locally sourced organic will always be tenfold better. This also applies to meats, dairy, etc.

Is It Safe?

Tons of people are doing it with absolutely no problems at all. That said, nothing is ever going to convince me that eating processed crap on a daily basis is good for you. Nutritionally dense food will always be better in my opinion, and no one’s ever going to convince me otherwise.

Of course, you could always combine all the tracking and calculating needed for IIFYM with a clean eating, Paleo or another regimen that focuses on healthy, unprocessed foods, in which case there wouldn’t be anything bad about it.

If you’re someone that’s previously suffered from an eating disorder, I wouldn’t recommend this type of diet because there’s just way too much tracking and weighing involved. There’s a good chance that you could simply underfeed yourself into starvation and relapse. If you’re pregnant, I wouldn’t recommend it either – You should be eating good foods that fuel not only your body, but also that of the one you’re actively growing.

Does It Work?

According to a whole bunch of different statements on the internet, it absolutely does. And, if you actually can track everything that you’re putting into your body and you strictly stick to your daily allowances, I see no reason why you wouldn’t lose weight. The protein fueled meals and fats should help keep you feeling full.

If you’re just looking to lose weight, the flexible diet (when followed correctly) should definitely help you out with that (and hey, with the holidays in the full swing of things it might not be a bad jumping off point). But if you’re looking to become healthier overall, there are quite a few options that are better and take a lot less work (click here for a list of the other diets and eating plans we’ve reviewed so far).

Remember: Pizza, burgers, and cake might taste good, but (proper macro content or not) not one of them will feed your body like a vitamin and nutrient rich meal.


Junk food vs healthy food

There is nothing wrong with the concept of adjusting your macros according to your personal needs. In fact, this can help you ensure you’re getting all the macro nutrients you need every day, and this is the best thing you can learn from IIFYM.

However, I would recommend you skip the Flexible Dieting part, meaning you shouldn’t eat just about anything to fill your daily macros. Besides protein, carbs and fats we need other nutrients (think fiber, vitamins, minerals….etc.) and you won’t get those from a Big Mac.

As always, there’s no better diet than the one focusing on a variety of single ingredient natural foods even if you can’t find or afford their organic alternatives, regardless if you’re an omnivore, vegetarian or a vegan.

So, the best thing you can do is to use IIFYM’s daily macro guidelines while eating a variety of whole, natural foods and steering clear of processed junk food which you could probably get away by eating it occasionally, but no more than that if you want to be truly healthy. If you do it like this, you have a powerful lifestyle change weapon at your disposal.

The Usual Statement

You should always consult with your medical professional or holistic practitioner before starting this or any other type of diet or making any huge lifestyle change, just to ensure that you don’t have any sort of underlying health conditions that you don’t know about.

Have you ever tried out the IIFYM/Flexible diet? Did you see results or did you find it to be just entirely too complicated? I’d love to hear your personal experience – Let me know in the comments section below!

The Best Thing You Can Learn From Flexible Dieting (IIFYM)

Remember to pin this article so that you can easily find it whenever you’re planning to start out your new diet. Don’t have a Pinterest account and not planning on getting one anytime soon? Not to worry – We can also be found on Facebook, Twitter and Google+.

This article contains affiliate links to products, services and other items we recommend and are relevant to the discussed topic. We receive a small commission from purchases made from these links, which helps us cover the costs associated with running and maintaining this website. If you decide to buy anything from our affiliate links, we are most grateful for your support!