The Most Straight Forward Guide To IIFYM (If It Fits Your Macros)

If it fits your macros, also known as IIFYM is a popular way of eating among the fitness community. Most of us have already heard of IIFYM before, but not everyone knows exactly how it works. Most people also don’t know the pros and cons behind IIFYM and how to make IIFYM work for you. IIFYM isn’t for everyone, but I’m personally a big fan of it. In this guide, I’ll detail out what macros are and how IIFYM works.

What is IIFYM?

IIFYM stands for if it fits your macros. Some people like to call if flexible dieting. Traditionally losing weight meant calorie tracking. Getting in fewer calories than what you are putting out means that you will lose weight over time. Eat more than what your maintenance calorie is and that means that you’ll gain weight. That type of diet might not work for everyone.

IIFYM eliminates the calorie tracking perspective, instead, you’ll be tracking your “macros”. As long as you hit certain numbers, there’s theoretically no limitation on what foods you can use to meet them. This is why it is called flexible dieting because of the fact that there are no food restrictions. This is however not necessary a good thing. We’ll go over why this might not be the best option later in this article.

To make IIFYM work, you have to understand the principal of key nutrients or things can go terribly wrong, but if you have a good understanding of macro and micro nutrients, then IIFYM can be an extremely flexible diet that you can actually stick to.

Macros, short for “macronutrients,” is the term used to describe the three major (or macro) nutrients: protein, carbohydrates, and fat. One of the biggest problems with traditional calorie tracking is that it’s hard to stick to. With macros, it’s more about eating a more well-balanced diet because if done right your macros shouldn’t lead you to eat a bunch of junk food that isn’t good for your body.

For example, let’s take a look at a sample macronutrient of a chocolate cake. According to FatSecrets, a chocolate cake with chocolate frosting contains 34grams of carbs, 10g of fats, and 2g of protein (rough estimate). If you eat 3 pieces of chocolate cake, you’ll be getting in approx. 103g of carbs, 30g of fats, and 6g of protein. Obviously, we all know that eating chocolate cake isn’t the healthiest option. If you know that your daily macros cannot exceed 150 carbs, then you might stay away from any more cakes for the rest of the day. This is a good way to keep your foods and nutrients in check. At the same time, you won’t go over your limits because you will be spending your other macros on protein for the rest of the day instead.

The good thing about IIFYM is that there is no restrictions or elimination of food groups, which means it is a diet that is sustainable. Another good thing about IIFYM, unlike fasting, is that there isn’t a certain time window of the day on when you can eat and when you cannot eat. This diet believes that your stomach doesn’t necessary have a clock or timer, as long as it fits your macros.

If performed correctly IIFYM will help you roll through your day with a good amount of energy and body balance.

Here are some benefits of being on IIFYM:

  • No restrictions or limits – As mentioned above, there are no restrictions or elimination making this diet much more sustainable in the long run.
  • Perfect for the social world – One of the hardest problems with going on another diet is that most diets tend to eliminate food groups or food types. For example, low carb diets like keto will fully eliminate carbs. Even though there are a lot of restaurants that offer low carb options, it can still be a hassle to get out of your way just to eat with a friend. Following an IIFYM approach promotes less stress in these sorts of situations. You can just eat more or less of a certain macro than planned at an earlier meal.
  • Performance – Due to the fact that IIFYM is a really well balanced diet, you should be able to up your performance and energy levels because you are having enough proper nutrients to help your body make it through the day. In the next section I’ll explain a bit more on each type of macronutrients and how it affects the body’s composition as well as performance.

How do macros work?

As mentioned above, macros are classified into three categories: carbs, fats, and protein. IIFYM believes that not one is better than the other, instead, you need all three and you must balance all three of them.

Carbs or carbohydrates

Carbs are the body’s primary source of fuel. It’s the first thing your body reaches for when it needs energy. This is why you see a lot of professional athletes such as basketball players consume a lot of carbs. They need it to power through their workouts and training. Without going too into detail, there are two main types of carbohydrates: simple and complex. Complex carbohydrates digest slowly and keep you full for longer while simple carbs digest quicker. Good examples of complex carbs are oats, brown rice, starchy vegetables, and whole-wheat bread. Good examples of simple carbs are muffins, cookies, white bread, white pasta etc. Carbs, in general, can be used post workout to give you the immediate fuel you need to recover from the workout. Some would consider that simple carb are considered bad carbs. Refer to the picture below for a reference on the different types of carbs.

good carbs vs bad carbs



Protein is essential in any diet because it is what helps you build your muscles. It also helps with the recovery of muscles after a hard workout. Protein is one of the key macronutrients essential for a healthy immune, cellular and hormonal function. One gram of protein provides four calories which are similar to carbs. Without enough protein foods in your diet, you risk becoming deficient in certain amino acids. The result? You’ll experience trouble in building muscle mass, low concentration and memory, mood swings, unstable blood sugar levels and trouble maintaining or losing weight. A huge mistake that beginners run into when trying to lose weight is cutting out the proteins. This can still result in a weight loss, but what happens is that you’ll also be losing muscles which will end up making you look more flabby.

Protein isn’t just important for muscles and body mass, but it also plays an important role in hair and nail growth. In addition to that, protein can help you feel full for longer, so make sure you consume your proteins.

According to the USDA, the recommended daily intake of protein for adults who are at an average weight and activity level is:

  • 56 grams per day for men
  • 46 grams per day for women

That is the bare minimum of protein that you should have every day. Of course, this varies depending on the type of diet that you are going for and your final goals. When you are looking to shed some fat, it is always important to up your protein to keep the muscles in shape.

Refer to the picture below for a list of foods that are high in protein:


The last category is fats. Fat is an essential nutrient involved in many bodily functions. It’s crucial for cell signaling and communication in the body, it allows your body to absorb vitamins, and it promotes an optimal hormonal environment in the body. Unlike carbs and proteins, fats contain 9 calories per gram.

Boy, do fats get a bad rep. For years, people use to think that they’ll lose weight if they cut out all the fat in their diet. It’s not that simple. Here are some of the things that can happen if you don’t eat enough fat.

  • Poor brain function – Your brain is primarily made up of fats. and requires a steady stream of fatty acids to perform optimally. Without fats, your mood will be down and you might not be able to focus as well.
  • Imbalanced hormones – Cholesterol and other fats play a fundamental part in building cellular membranes and hormones. Certain kinds of fats, including cholesterol, also act like antioxidants and precursors to some important brain-supporting molecules and neurotransmitters.
  • Overeating – Fats helps keep us full for longer. This is why low carb and high fat diets are so popular because they are able to eat less and feel full for longer.

With that said, there are good fats and bad fats.

Good Fats are monounsaturated and polyunsaturated fats. These fats:

  • are shown to improve cholesterol levels
  • may help reduce risk factors of heart disease.
  • helps with reducing the risk of developing diabeties.
  • are required to maintain a healthy immune system
  • promote brain function and awareness
  • protects the liver from damage and toxic
  • can help with repairing gut problems

Some foods that contain healthy (good) fats are avocados, almonds, eggs, fish, seeds, olive oil, coconut oil, yogurt and more.

The “Bad Fats” are considered to be trans and saturated fats. Although, there has been new research saying that saturated fats aren’t necessary as bad as they are thought to be. Bad fats:

Bad fats:

  • Usually, raise LDL which is the bad version of cholesterol
  • leads to a series of chronic and heart diseases.
  • Leads to stroke

The bad fats are usually found in fried foods, battered foods, pies, cakes, chips, and many more junk foods. It’s best to avoid these as much as possible as they are empty calories and they aren’t good for your health in the long run.

good fats vs bad fats


The downsides and pitfalls of IIFYM

No diet is perfect and there’s always a downside to everything. One of the reasons why IIFYM receives a lot of rants is because a lot of people aren’t approaching IIFYM correctly. This has given the approach a reputation as being unhealthy, even though it shouldn’t be.

One of the downsides to IIFYM is that it is too flexible. This leads to a lot of people eating a bunch of junk as a part of their daily diet. Most people don’t understand the difference between good carbs and bad carbs. Because of this reason, they think they can consume any food and still hit their macros. The problem with this is that if you are not eating nutrient dense foods, you will end up feeling more hungry and you won’t get enough nutrients to allow your body to function correctly.

The second downside and pitfall to IIFYM are that most people on this diet miss out on their micronutrients. Macronutrients are the carbs, protein, and fats, whereas micronutrients are the essential vitamins and minerals. They play crucial roles in your training and recovery. Beginners tend to reach for cookies to hit their carb macros over something more nutrient dense like broccoli or asparagus. Fortunately, this is an easy problem to fix. Make sure you choose healthier options when it comes to hitting your macros. Opt for veggies over cookies, opt for fruits over ice cream etc. In conclusion, to make IIFYM work at it’s best to choose healthier alternatives to hit your macros with.


This is also why a lot of people argue that a clean eating diet will help you better in the long run because clean dieting allows you to make good choices while keeping the overall calories low.

How to start IIFYM

The first thing you need to figure out when deciding to start on IIFYM is your end goal. Are you looking to gain mass or cut weight? If you are looking to gain mass, the general rule of thumb is to eat 500 calories above maintenance. On the other hand, if you are looking to lose weight, you need eat 500 less calories than your daily maintenance. This will help you determine your desired macros. The basic calculation goes like this:

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

Doing the basic math and finding out your calorie needs, you’re able to determine the number of proper macros you need.

Here is a calculator that you can use to calculate a number of calories that you need. Just fill in the information and it should give you an accurate number.

Finding your IIFYM split

Once you figured out your ideal daily calorie intake, you will need to choose a split. This varies depending on the end goal. The general rule of thumb is:

  • Bodybuilding – 40% protein / 40% carbs / 20% fat
  • Performance – 50% carbs / 30% protein / 20% fat
  • Lose weight – 40% protein / 30% carbs / 30% fat

You would take the ideal calorie number that you generated above and split it accordingly based on the split that you choose to go with.

There is no “wrong” macro split. It will ultimately come down to what you feel most comfortable with and can maintain. As long as you’re in a caloric surplus or deficit, you should progress in the right direction. Your split will make a difference in how you feel and perform along the way, and in how fast you get where you want to go.

Apps that help with tracking your macros

Of course, you can always just write down everything, but that would be a pain. Luckily we have technology nowadays that can help you with keeping track of everything. Some of my favorite apps include the following:

FatSecrets – This is my most favorite app when it comes to tracking macro and calories. It is extremely useful friendly and they have a tab specifically made for macros so you can see your progress. It will even notify you if you went over your macros for the day.

MyFitnessPal – Most fitness and bodybuilders live by this app. It was one of the early adapters in the fitness space. There are a few things that I don’t like about this app. First, a lot of the data are inaccurate. There are a lot of user generated data, making it difficult to know which ones are correct and which ones are not. The second thing that I don’t like is that there are a lot of display advertising which I’m not a huge fan of.

Loseit! – This is a rather new app that I discovered which allows you to take a picture of a photo and the app will try its best to guess what food it is. I gave it a try and while it’s an awesome app, I liked Fatsecrets a lot more.

There are a lot of other apps out there. If you come across one that you think it’s good, please let me know by commenting below!

Should my macros stay the same every day?

This is fully up to you. Personally, I like to change my macros depending on my goals and my performance that day. I like to keep the carbs lower and protein higher on my rest days, while increasing my carbs on my workout days. The thing about dieting is that there isn’t a single method that works for everyone. We can only follow certain rules of thumb, but at the end of the day, you have to figure out what works best for your body.


In conclusion, IIFYM is flexible and it’s a diet that most people can stick with. Just don’t make the mistake of filling up your macros with foods that aren’t good for you. Similar to any diet, keep testing and find the best fit for you. You can always have your cheat meals just like any other diet and if you have to fill up your macros, then fill it up using foods that are filled with nutrition.

Have you guys tried IIFYM? Are you guys on it right now? Would love to hear your results and thoughts.

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