The story
By a metaphor in which mental preoccupation is portrayed as noise inside one's head that cannot be turned off, somewhat like an earworm. Widely used since the early 2020s, when indications for using the GLP-1 receptor agonist medication class expanded beyond diabetes treatment into weight control for anyone with or without diabetes; not in widespread use before that. Attested since 2007.
Etymology from Wiktionary, CC BY-SA 4.0.