Calories in Calories out, fat storing, macros, protein: A Clarification
Hi,
Energy from protein cannot really be stored as fat, as the conversion of protein to bodyfat is more (or equally?) expensive (in terms of energy) as the bodyfat revenue. So it's a zero-sum affair. I trust Feigenbaum on this.
My question is an arithmetic one. So, let's say Johnny needs 3000kcal per day for maintenance. If he's at a calorie deficit, he will lose weight (whether muscle mass, bodyfat, or both), and I don't really see any way around that. But if instead he consumes a maintenance amount of energy (3000kcal) or above ...
... let's say he gets 2000kcal from fat and carbs, and 1000kcal from protein. I'm guessing that he'll use those 3000kcal for fuel and thus maintain his bodyweight, unless he uses the 2000kcal from carbs and fat for fuel, then 1000kcal worth of bodyfat for fuel, which I'm guessing isn't the case. If he consumes 2500kcal from fat and carbs, and 1000kcal from protein, he'd be at a 500kcal surplus. What happens??? Will he use the 2500kcal from fat and carbs for fuel AND 500kcal from protein for fuel, and just convert the remaining 500kcal from protein to heat energy, i.e. will he maintain his bodyweight despite of a calorie surplus... OR does the body prioritize fuel sources in such a way that he will gain bodyfat? As in, perhaps he uses the 1000kcal from protein for fuel first, then 2000kcal from carbs and/or fat, and then stores the excess 500kcal of carbs and fat as bodyfat?
All I know is that protein virtually can't be stored as bodyfat, and that calories in calories out is taken as an accurate principle. This leads me to believe that protein is prioritized as a fuel source, at least over fat. I mean, otherwise one could be at several thousand kcal per day surplus and still maintain bodyweight, AS LONG AS the energy from fat and carbs remained below daily energy consumption. How does this work? Does it depend? Like keto for instance, can he be on a calorie surplus and still lose weight? If keto-Johnny ate 2500kcal worth of fat and 1500kcal worth of protein, would he first burn all the eaten fat, and then 500kcal worth of bodyfat because his body prefers fuel sources in that order (fat first (eaten fat > bodyfat), everything else second)? Or would he burn the eaten fat, then 500kcal of protein, and then convert the rest of the energy from the protein to heat, and thus maintain his bodyweight despite of being at a 1000kcal surplus? Also, if he ate 3500kcal of fat and Xkcal of protein, I'm thinking he'd gain 500kcal worth of bodyfat...
IFF it's true that protein can't be stored as fat (again, I trust Jordan), and that calories in calories out holds, it would all seem to come down to the body's prioritization of fuel sources:
If protein is less preferred than carbs and eaten fat (but not bodyfat), as fuel, it would seem to be the case that one could lose weight at a calorie maintenance or even surplus, AS LONG AS the energy from fat and carbs are below 3000kcal, alternatively one could maintain bodyweight at a calorie surplus if the energy from fat and carbs = 3000kcal. If protein is instead more preferred than let's say fat, but less preferred than carbs, the math would change somewhat. But again, this whole thing seems to come down to prioritization of fuel sources. I'm sure this prioritization can and does vary but left that out intentionally to make the question more black and white.
Anyway, I'm sure You get the point of my long ass question. How does this work?
Please clarify
Thanks!