Yeah, Amane throughout the opening, her actions go from "satisfying her urges" to really satisfying her more clinical urges.

She's constantly noted as sneaking food, even from the person she's making a literal dietary diary for, hoarding, the topic of Japanese teenage girls needing survival training came up and she noped out of the topic in the span of a dialogue box, her introduction and posturing as her "role", about a third of the scenes she's in makes some quiet allusion to her true situation, that you brush off on first read.