I'll say what I remember they can't have... No raw Brussels sprouts or raw beans. Cooked is fine. No green bananas, ripe is good. No onions, like dogs onions are poisonous. No chocolate, but a little dark chocolate is okay now and then. Not too much protein unless pregnant, but a in small portions is fine. Lettuce not good. No full cream milk. No raw potato, but they love it cooked in any form.
Tomatoes good. They love porridge, rice, pastas, yoghurt. Most fruits and veg. Love grapes, it amazes me how they manage to peel grapes and baby tomatoes. Cereal. Peanut butter. Ooh, we managed to get almonds in their shells once they love that. Not too many sunflower seeds due to fat content. Lentils and baked beans or mixed beans and chick peas in small amounts.
Some ideas for you to mull over. Baddies on top then goodies on bottom. These are extras though, they still need the rat food for all essentials. My boys are spoilt rotten though.they also get bits of rusk or biscuits occasionally. They're so spoilt in fact that they want what we eat not their rattie food.