First it does affect weight, I don't recall it affecting which adult you get in this version, but it might create "poor care" adults. It does play a role in select games (bump-being the first one to come to mind) and health, your Tamagotchi is more likely to become ill if they're overweight.what it says in the title. I'm wondering if feeding my tamagotchi its favourite foods will impact what it grows into on the v3 specifically