She sucks human fat to feed herself, then runs a successful weight loss business. Supernatural.

The show's name: Supernatural (S09E13). A monster that feeds on human fat. Dean and Sam are hunting a serial murderer, they investigate recent murders where the victims were hundreds of pounds lighter after their deaths. Suspecting witches, the two go undercover at a fancy day spa that all of the victims had attended for weight loss. #movierecap #moviereview