Its good to have all. Im not sure if lettuce has much in the way of nutrients either. Carrots are good. Throw in an orange, apple, collard/kale and cricket crack or other dry food that adds additional nutrients. A chameleon is only as healthy as the food he eats ( ok, that's a bit of an overstatement, but I hope you get what I mean) the better the gutload, the better nutrition your Cham is getting