I honestly believe that gutloading your bugs with nutritious food that is safe for chameleons is the best way to go. Feed him a variety of foods like crickets, super worms, horn worms, silk worms, dubia roaches, banana roaches, grasshoppers, etc. He will love the variety.
it also depends on his mood AND the lighting of his cage. Get him outside IF HE LETS YOU (otherwise it'll stress him) and let him soak up some sun.