To answer your question, and I am sure you will hear the same thing from other forum members, this kind of food is probably the worst thing you could give him actually, but it is not your fault, it is the fault of the horrid companies that actually have the nerve to call it "rat and mouse" food because it has so much filler junk in it like sunflower seeds and so forth. This is the type of food that would be more fitting for hamsters/gerbils, but rats need to have the lab block type food, like Harlan Teklad or Oxbow Regal Rat lab blocks. If you need something for the time being, while you check out the websites some members gave you for places to order Harlan Teklad, you could try Mazuri brand rat lab blocks which are usually carried by pet store chains. Mazuri is not as good long term as Harlan Teklad or Oxbow for rat blocks, but it is far better than the mixed seed mix. 