I think this shows your problem right? You have known the way but you refused to go down on it. "Appetite" here is more of a mental thing, much like the "hunger" that we know.

But I don't know man, what's the problem when you are not gaining fats?? Burnt a hole in your wallet? Too taxing for your body? Then just make better food choices and cut out the craps.

Not really in the place to advise since I'm not blessed with that genetics.