if you mean as in gaining xp, yeah that is how you do it, if you mean increasing the SIZE, you need to do events (working and the tournament stuffing) and cook a special food (unlocked late in the game) to get the biggest size
So for the cooking food thing, it’s just that there a specific one that I need to cook to increase belly level? I see. might I ask which one so I know what to look out for?
I cant remember what it is (been a while since I last played it) but the description states it is a a meal for size