Is it normal for my hedgehog not to try any new foods?

My hedgehog will eat his dry cat food but I can't get him to eat anything else. I've tried apples, carrots, strawberries, and lettuce and he'll nibble at them and then self-annoint himself but he won't eat any of it. He used to eat a little bit of the carrots when I first got him (I've had him for like a year now). Also, when I first started feeding him mealworms he loved them but after a several months he was less interested and wouldn't gobble them up immediately like before--he'll bite into it and leave it and if i put it in his food dish he'll eat it later. I keep reading on the internet about proper nutrition for hedgies and how they love treats and I'm getting frustrated/concerned. Is this normal behavior?