Johann Hari’s Magic Pill opens with the author, aged nineteen, attending a student drama festival in Scarborough, where he falls in with the entertaining, if heavy, Hannah. That evening they tour the seaside town’s fast-food outlets – shops selling fish and chips, kebabs and fried chicken. This marks the beginning of a close relationship, fuelled by ‘our love of bad food, and our commitment to consuming it in epic quantities’. Twenty years on, he receives a phone call and learns that Hannah, though still only in her mid-forties, has suffered a fatal heart attack.

In the meantime, his weight has risen steadily to fourteen and a half stone, which, for his height (five foot eight), is three stone too much. Shocked by his erstwhile friend’s premature death, he makes a ‘snap decision’ to start the recently licensed weight-loss drug Ozempic. As he stabs his stomach with the first injection, he has a flashback to the hundreds of McDonald’s outlets around the world he has patronised over the years.

This certainly makes for a colourful introduction – perhaps a little too colourful, given Hari’s reputation: he was called out over a decade ago for creative reporting. Since making a public apology, he has authored bestselling popular science books on depression, addiction and the harms of digital technology.

Magic Pill looks