What do we know of the history of eating disorders? Specifically between the 16th and 19th centuries and localized to the Western world.

by 4THOT
Vespertine

This earlier answer by u/Ilosa summarises various instances from the period you mention.

u/sunagainstgold has written several answers relating to medieval saints and mystics that would be relevant; I haven't yet tracked one down, but in this long question post mentions several relevant points that may help with your question. (The answer by another user is primarily about the 20th century and unfortunately conflates mass practices from the ancient world.)