In step 1 of the macro calculator, the most accurate formula is the Lean Mass option. This allows you to enter your body fat percentage, which calculates your nutritional needs off of your lean body mass (muscle mass) rather than your total body weight.
An easy way to break it down in to very simple terms; since muscle is alive and requires a steady flow of nutrients in order to survive and grow, while fat on the other hand is not alive and requires hardly any attention to maintain it’s mass therefor it makes the most sense to base our nutritional and caloric needs off of our lean mass, which is what makes this formula in our calculator the ideal option when calculating our macros.
This is obviously an overly simplistic way to look at things and there is much more biological activity happening but you get the point.
“When we focus on feeding the muscle, rather than feeding the fat, we end up getting less total calories to consume.”
Please keep in mind that the IIFYM Calculator is just a tool that will help you get close to your actual macros. The numbers it gives you are just an estimate. It is up to you to change you macros based on the changes your body makes after following the direction of the Flexible dieting calculator.
If you still find this all confusing and would like us to dial in your macros for you you might want to consider signing up for our IIFYM Starter Kit: Click here to get access to your customized macro blueprint