an animals natural instinct cannot be taken away, they are insectivores primarily, and feed on fruit/nectar as well, which is how the whole baby food thing got started.
an animal will eat it, because it has to, to survive. does a crested gecko prefer insects to CGD or CGD to insects? that we will never know, but I have read articles of people that just stop feeding their gecko all together until it finally eats the CGD to be able to survive.
i know people that HATE CGD, they think its all just typical junk that is being produced to make more money. I dont feel this way, but I know several who do.
i also know many breeders that refuse to cut out insects all together even while using CGD because they also acknowledge that a crested gecko feeds on insects, and they should still be able to feed on them occasionally even when using CGD.
i am not one of the keepers that feeds fattening wax worms and unhealthy mealworms, i feed gutloaded crickets, and a bit of baby food, i have also considered using CGD, but I personally dont find the need to. my crested geckos are very healthy and active feeders, and they are doing just fine without it.
i dont knock anyone who uses it, what i dont like is people telling me that my opinion is wrong, because opinions cant really be wrong, they are just the personal feelings of the person that is voicing them. IN MY OPINION, i think even while using CGD that insects should also be fed occasionally because it is natural for them.
this all got started because several people felt that not wanting to make a drive wasnt a very legitimate excuse, but hey, if it works for him, more power to him.
as far as brain capacity goes, some times my cresteds wont even eat their baby food when its in there, but crickets they nail every single time, so i wouldnt say that they dont have the capacity to decide what they would rather eat, because im sure they do. even certain leachianus in the wild were found feeding on a type of berry almost exclusively, even with everything that was around them, they fed on that, for some reason that herpetologists aren't quite sure of, so i would DEFINITELY say that these animals have the capacity to decide what they want to eat.
but like i said, to each his own.