I would be very interested in understanding the limitations in using this method. For example, in using the regular Macro Calculator apps that are everywhere, you have to select your subjective activity level, except doing “moderate activity” with a high vs low FTP, or for 1hr vs 1.5h can create its own 300+ calorie deficit without knowing any better, the subjective experience doesn’t change but the energy output changes significantly.
In my situation I have the opposite concern to most people here, I work a physical job and train when I can, so using this 40-45kcal/kg/ffm method can leave me under-eating since it doesn’t state what the equation assumes is considered baseline activity (NEAT). In some quick reading for where this equation and the 35/40/45 standards were determined I found that the studies were done on suspected RED-S athletes who were HS/University female students who were explicitly told to not perform any additional effortful activities outside of their sport, except walking. So if you work at your desk 8-10hrs a day then walk your dog, that applies just fine, but for those of us with higher energy output throughout the day than the equation accounts for still leaves us chasing a “multiplier”, meaning 40/45/50?kcal/kg/ffm that suits our energy needs.
Any thoughts?