“If It Fits Your Macros”, or IIFYM for short, is probably one of the most amazing yet totally misunderstood dieting concepts circulating amongst bodybuilders and fitness enthusiasts in general.

IIFYM started as a phrase from a BodyBuilding.com member has quickly caught on and proceeded to cause an uproar against fitness and bodybuilding diet “purists”.

Following the IIFYM is a quick and simple response to the overwhelming number of questions about whether or not someone can eat a particular food, like an In N Out Cheeseburger without having sacrifice your dieting efforts, whether you are trying to build lean muscle or lean down.

What Is IIFYM?

IIFYM teaches us that these so called ‘dirty’ or ‘junk’ foods are ok to eat as long as we stay within your own required calorie intake for the day. This applies to both bulking (building muscle) and cutting (losing fat).

What bodybuilders have known for years is we all have different bodies, different metabolisms, different muscle mass and a hundred other things that set us apart from everyone else on this planet – age, bad genetics, hormone imbalances, thyroid problems etc. IIFYM simply tells your how many calories you need based on your gender or even based on your weight loss goals, it looks at every person individually and tells them, with a made up stat of 95% certainty how many calories to eat. This is done by simply calculating how many carbs you need to maintain your current weight at your current activity level. This is called your TDEE or “total daily energy expenditure.

IIFYM doesn’t care if you eat hamburgers, or tuna. IIFYM doesn’t doesn’t care if you chose ice cream over cream of rice. The idea of IIFYM is simple – you eat whatever foods you like the fill your allotment of proteins, carbs and fats!

What Are Macronutrients or Macros?

So to try to make it as simple as possible:


Protein helps the body grow, builds muscle and give us energy. Protein-rich foods include meats, eggs, avocado, nuts and beans.


Carbohydrates are sugars that the body uses for energy. Simple carbohydrates, also called simple sugars, provide the body with quick energy. They are found in fruit, milk and white sugar. Complex carbohydrates, known as fiber and starch, are broken down in the body slower than simple carbohydrates. They are found in vegetables, bread, rice, oatmeal, whole grains and peas.


Fat isn’t your nemesis. It isn’t the “Boogeyman”. Your body needs fat to grow and to process vitamins. There are many different kinds of fats. Polyunsaturated and monounsaturated fats are good for your body. These fats include nuts and fish, as well as olive, peanut, safflower and canola oil. Other kinds of fat, including saturated and trans fat, also called hydrogenated oils, can increase the risk of certain diseases. Saturated and trans fats are found in butter, fried foods, baked goods, fast food, whole milk and in meat from animals. The majority of fats in your diet should come from polyunsaturated and monounsaturated fats.

So, How Do You Calculate Macros?

This is one of the most common questions I get from friends and people at the gym. People are literally lost, but once it is explained, it makes planning your diet around your fitness goals crazy simple.

So, for me, my TDEE is 3500 calories. This simply means that in order for my body to maintain its current weight, I need to eat 3500 calories per day. If I am trying to cut, I simply decrease my TDEE by 500 calories per day or if I am trying to “bulk” I add 500 calories. Then I plan my meals and see how my body responds. To do the following calculation, you will need to know how many calories are in 1g of protein, carbohydrate, and fat.

  • 1g protein = 4 calories
  • 1g carbohydrates = 4 calories
  • 1g fat = 9 calories

The above just shows how much calories you will get from consuming 1gram of each, and notice that 1g of fat gives more than double the calories of proteins and carbs.

Calculate your daily protein and carbohydrate caloric intake:

    A lot can be said about setting your macro ratios. Most people tend to stick with 40/40/20, that is your diet consists of 40% Protein, 40% Carbs, 20% Fat calories.

  • Your daily calories X 40% = calories coming from proteins
  • Your daily calories X 40% = calories coming from carbohydrates
  • Your daily calories X 20% = calories coming from fats

If I was cutting, for me, these numbers would be:

  • 3000 X 40% = 1200 calories from proteins
  • 3000 X 40% = 1200 calories from carbs
  • 3000 X 20% = 600 calories from fats

So, now that we know I need 1200 calories from of protein, 1200 calories from carbohydrates, and 600 from fats to hit my daily macro goals. It is much easier to look at these values in terms of grams, that is how everything is calculated when you look at the nutrition label on your bag of Doritos

Calculate your daily protein, carbohydrate, and fat intake in grams:

  • Protein: 1200 calories / 4 calories per gram of protein = 300g protein
  • Carbs: 1200 cals / 4 cals per gram of carbohydrate = 300g carbs
  • Fat: 600 calories / 9 calories per gram of fat = 66.6g fat

So, I should aim to take in 300g of protein, 300g of carbohydrates, and roughtly 67g of fats. I typically spread this out over 6-8 meals per day. Pre-Workout, Post Workout, Breakfast, Snack, Lunch, Snack, Dinner, Snack. Sometimes I will combine two meals if I know I am going to be eating a huge meal like pizza or burgers and fries.

IIFYM gives you more food options when trying to hit your macronutrient targets by end of day. It allows you to select foods that you LOVE. Now, most experts agree, that it is really tough to hit your macro goals without including the staples like eggs, lean cuts of steak, oats, grits, brown rice, etc.

IIFYM eating flies in the face of conventional dieting, and the notion that anyone who wants to get in shape has to eat a stringent diet, composed of a limited number of so-called “clean foods,” needs to eat at precise times throughout the day, must have certain types of food pre and post workout, and that any deviation from this strict structure is breaking the rules of dieting.

IIFYM Tips and Advice

There are several issues in thinking this:

1. You should set a minimum fiber intake (usually around 20-25g for women and 30-35g for men) which will necessitate lots of vegetables, pulses, fruits and minimal processed sugar.

2. If you do get all your calories from junk, you’ll probably feel pretty damn lousy – definitely not what you want before a heavy squat session.

3. Check yourself out in the mirror. The scale is a good tool, but the mirror is a better one. If you notice yourself getting softer or losing definition, then you can lower your calories or adjust your macro percentages. If you are losing weight when trying to bulk, then increase your calories.

So, You Want to Give IIFYM a Shot, Now What?

I don’t recommend just winging it. Sit down, come up with a plan. Every single food item, menu item from your favorite restaurant has the nutrition facts posted on their websites. Creating a meal plan is a great way for you to know what your are going to eat that day and how much you need to eat to hit your goals. From there, it’s just a case of tracking what you eat using a calorie counting site or app. I use MyFitnessPal. It is easy to use, very intuitive and it’s on my phone, so I can punch in meals when I am out to eat. These are incredibly easy to use once you get to grips with them. Play around to find what foods you can use to meet your macronutrient needs.

Here is a great video by Dr. Layne Norton in regards to Clean Eating vs IIFYM:

Source – http://www.iifym.com

About The Author

Brian E. is from southern California and has worked for names like GNC and Vitamin Shoppe as a supplement expert and consultant. He currently lives in Utah and is studying marketing.

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