IIFYM - If It Fits Your Macros

IIFYM is one of the best things people can do to fix a diet that is becoming unsuccessful. I say this because it will help curb binges, cheating and guilt which I have found to be three of the biggest factors in people quitting a healthy eating lifestyle.

Imagine eating a diet consisting of the worst foods you can think of from McDonalds, but here and there you sneak in some vegetables or a healthy protein source. Will it effect your body composition in a good way? No, it won’t. Now let’s imagine that you have a superb diet consisting of good protein sources, whole foods, vegetables and fruits, but every once in awhile you eat a Big Mac. Is it going to effect your body composition in a bad way? No.

The phrase If It Fits Your Macros (often abbreviated to IIFYM) refers to meeting the individual macronutrient needs relevant to one’s goals and then filling the remaining calories with foods of personal preference. Meaning, eat whatever you want as long as it fits the macros. Don’t get it?


  • 200lb man at 20% body fat wants to lose weight
  • Maintenance Calories: 3000
  • Calories to cut: 2400 - this is a 20% caloric deficit
  • 1.5g protein per lb/LBM: (1.5 * 160) 240g
  • 0.45g fat per lb/BW: (200 * 0.45) 90g
  • Calories from fats + protein minimums: (240 * 4) + (90 * 9) = 1770
  • Calories from reaching minimums taken from calories to cut: (2400 - 1770) 630
  • He has 630 kcal left to fill with whatever foods he chooses (pancakes, pizza, cake, ice cream) and still lose weight as a result of remaining in a calorie deficit.

How to easily calculate (estimate) your caloric intake:

Something I’ve always followed as a bit of a catchall and then I just adjust if I’m losing/gaining weight based on what my goals are. 

  • Your maintenance caloric level is 14-16 kcals per lb of body weight
  • Your fat loss caloric deficit is 11-13 kcals per lb of body weight
  • Your size gain caloric surplus is anything over maintenance

Keep your focus on getting the majority of calories from protein sources and whole foods to establish a good base of vitamins and minerals in your diet.

How to easily calculate (estimate) your macro-nutrient intake:

  • Protein: 1g - 2g of protein per pound of bodyweight.
  • Fat: 0.35g - 0.45g of fat per pound of bodyweight.

Remember that protein has 4 kcals per 1g and fat has 9 kcals per 1g. Now, just fill in the rest of your caloric intake with whatever you want (poptarts, pizza, waffles).


  • Try to get most of your macros from whole foods. They are high in micronutrients needed to maintain overall health.
  • Tailor your meals to suit your individual preference. 6 meals a day is the same as 3 meals a day. There is no difference.
  • Timing your nutrients is not necessary. There is no universal macro or calorie breakdown you should be eating pre and/or post-workout. Overall micronutrient, macronutrient and calorie intake relevant to your goal(s) is far more important.


What “eat whatever you want as long as it fits into your macros” means is basically, eat right, but don’t get all caught up in the whole ‘clean vs dirty’ food debate that seems to still go on. If you want to eat whole grain bread, oats, brown rice, etc. etc. Then do it. If you want to eat white bread, white rice, and pop tarts, as long as it fits in with your other macronutrients and your goals in terms of caloric intake then it isn’t going to make much of a difference in the long run. It all comes down to personal preference.

So, basically don’t get into the whole “If I have ice cream I’m going to get fat” or, “I’ll never have pizza again” mentality. If you want it, you can have it, just make sure it fits in with all the guidelines above.

If it fits your macros, then eat it.