“I don’t think any of them are lying,” he goes on, “they are just stuck in this strange world of false belief, which is fascinating. How can you look at NHS guidelines on how to eat healthily and go, ‘Well, I know better than that’? Maybe if you were a professor of dietetics or nutrition, you might disagree with some stuff. But how as a 19-year-old blogger you can look at it and go, ‘No, that’s wrong. This is right,’ I don’t know.”

How did we arrive at a place where avocados outsell oranges, where coconut oil, a once-cheap saturated fat, is reborn as a super-ingredient with miraculous, health-giving properties? (Paltrow’s website Goop also proposes using it as a mouthwash and sexual lubricant, prompting Warner to joke, “Separately, I hope.”)

For Warner, part of the explanation is an adaptation of psychologist Daniel Kahneman’s theory that people are brilliant at creating a narrative from minimal evidence. Kahneman calls the brain “a machine for jumping to conclusions”.

For Warner, part of the explanation is an adaptation of psychologist Daniel Kahneman’s theory that people are brilliant at creating a narrative from minimal evidence. Kahneman calls the brain “a machine for jumping to conclusions”.

“We really struggle with uncertainty,” explains Warner. “We really want to be able to say: ‘Is coffee good or bad for us?’ Well, it’s not good or bad for you, it just is. And we have to accept that; that’s what science says. So your brain goes, ‘I don’t like that level of uncertainty.’ Certainty is really appealing for a lot of people and that’s what a lot of these people are selling – certainly at the darker end.”