Sweetchi are a species of humanoids made of L-glucose (common glucose has right-handed chirality). Sweetchi don’t have to eat to sustain themselves, they instead absorb magic from the atmosphere to sustain themselves, so they only eat for flavours. Technically, they could eat each other for more sustenance, but that leads to problems, like how cannibalism leads to prion diseases.
While technically edible for other species, this would likely cause them to explode due to magic overload. Due to the chirality of their glucose, eating a sweetchi is like eating pure magic, as other species' bodies do not interact with L-glucose as sustenance, which would offset the strength of the magic.