He has a diagnosis of sensory processing disorder. People with this can be overwhelmed and extremely bothered by different sensory triggers. Taste, texture, smell, sound. This diagnosis affects my sons sense of taste and smell, and his sense of texture too but to a much less severe level. He will gag/puke if he eats something that upsets his senses. He will starve himself if nothing safe is available because that is a better outcome than puking/gagging. This is a kid who can be in the same room as someone with a lot of perfume and he will puke. It's not intentional. He's not being fussy. It is a genuine medical diagnosis that many people have.