Could others be sneaking him food? Or he sneaks in a few bits from the girls bowls?
My biggest problem is everyone wants to feed Kaji. And I mean everyone!! My mom and dad feed him while I'm at work, my brothers love to feed him chicken when they're home on he weekends, and my dad and I argue about the nightly cookie. He wants to give Kaji 3, and I say one is enough. The argument is part of the nightly ritual.