It depends on the animal, and what you are feedng it. If the chameleon has not been treated for parasites, and you are feedin git wild insects, then it will require more food. If it is treated for parasites, and is getting farm raised insects, then feed less.
Food requirements for a captive bred, parasite free chameleon that eats fat, farm raised crickets and superworms are much lower than a wild, parasitized chameleon, that eats a variety of flies, grasshoppers and beetles.
Plus, if the chameleon has a lot of space, it can hunt. That excercise is important, and will mean the animal needs to eat more than if it were in a small cage.
