What if there was a curse that worked like forest knights leveling mechanic?
Youd get limited by your level cap, and till you level up through activities and defeating the residents of the forest or someone else the actions that grant you muscle, fat and other stats just dont?
Maybe when you reach the level cap the growth halts, but when you reach new level you get the changes stored since you grinded for them whilst being capped?
Just a thought.
Also i think there should be a weapon on the same level like the sword that utilizes your fat, cus right now belly flop feels less usefull because strike can scale with Gain power spell.