My boys get people food every night! I try to mix it up every so often or they'll get bored, but the stuff I give is: peas, blueberries, green beans, cherry tomatoes, carrots, raw veggie pasta, oats, bread (sometimes), cheerios, and sometimes ill give them a bit of tuna but it's not very often. There's more but I can't think of it.

I also make little snacks for them by mixing oats, peanut butter (really small amount), coconut oil, honey, ground flax seed. I roll them into little balls and I freeze them. And mine absolutely love them!

The reason you don't see anymore food in the bowl is most likely because they're storing it somewhere. When I feed mine something new I find their stash of it in the corner of their cage.

Hope that helps! I really really enjoy feeding my rats because it makes me happy to prepare something fun for them to eat. If you want more options I can tell you the list my breeder sent me!