Thin Girls: A Novel by Diana Clarke

Identical twin sisters Rose and Lily diverge as Rose develops severe
anorexia while Lily binge-eats; the novel follows Rose through an
eating-disorder facility, toxic relationships, and recovery as she
reconnects with former friend Mim.

This book contains; alcohol, alternate gender or sexual ideologies,
anxiety, BDSM, body horror, body shaming, bullying, child abuse,
controversial gender and social commentary, crude and explicit sexual dialogue, death/grief, deception, depression, derogatory terms, discrimination, disturbing psychological and body-related imagery, drugs, dubious consent, eating disorders, erotica, explicit sexual activities/nudity, gore, hate speech, kinks, misogyny, non-sexual nudity, oppression (themes), parental neglect, patently offensive sexual content, pervasively vulgar content, porn, profanity, prurient behaviors, self-harm (excessive), sex exploitation, sex toys
(referenced), sexism, sexual nudity, smoking, suicide ideation, theft,
toxic relationships, unvetted website references, victim shaming,
violence, and voyeurism.