I use carrots for the mealies / supers. Their bedding is Oat so they get plenty of food from that. For my dubia I use carrot / variety of green / and sometime the gutload thing you get from petstores. And I sometime dust the food with a lil of calcium and stuff like that to make them a bit healither
I use all kinds of cereals I could find on the shelf for the mealies, e.g. oatmeal, wheatgerm, bran, muesli...etc; and for the dubias, I blend the cereals + dry cat food into a powder. I will change out the roach food every 2nd day, so their food remains fresh and dry. For moisture, I use apples, oranges and carrots.