Birmingham teacher Dan suffers from “severe bloating” and toxic flatulence, earning him the nickname in his household of “beef bum”. Wife Natalie has IBS and, we are told, can have “days between poos”.

Quite why you’d go on national TV to say so is for them to know, but the Sharp family of seven were happy to reveal all in Michael Mosley: Secrets of Your Big Shop (Channel 4, 15 January, 8pm).

Well, almost all. They took Mosley through their diet, which he suspected to be the root of their ills. And by their account – lots of veg, chicken, fish and fruit – it sounded like they ate “pretty healthily” Mosley said. “But something is not adding up”.

With the backing of Asda, Mosley rigged the Sharps’ local supermarket with secret cameras while they did their weekly shop and awaited them at the checkout. “We’re in trouble here,” said Natalie.

At home he split their basket into healthy and unhealthy tables, the latter piled far higher. “A sugar fest,” Mosley noted. Busted.

Mosley also explored TikTok health hacks – including drinking liquid chlorophyll to boost health. “The very faintest taste of swamp water,” Mosley concluded, but it “doesn’t do anything good”. The viral 10-day egg diet was also given short shrift.

He put the Sharps on a healthier diet – and after nine weeks, Natalie’s IBS symptoms had disappeared and she was slimmer and more energetic.

And, to the relief of everyone around him, Dan revealed: “I can let one go and no one really notices.”