Did your grandfather also become unable to stomach food because he was searching for "gourmet" (whatever that means)? If not, then Mana's situation is utterly ridiculous.

Also this is a thing: https://en.wikipedia.org/wiki/Supertaster

I GUARANTEE you that Tsukuda doesn't know what that is. He just went with whatever seemed like the most edgy thing.

"One day, in her never-ending quest for gourmet, it seems Mana-sama completely despaired the concept of taste itself. As a result, she became unable to stomach food."

This is completely meaningless, it just sounds like something straight out of /r/im14andthisisdeep. Tsukuda probably doesn't even know what he's writing anyway.