Whole Foods chief executive John Mackey has told shoppers he sells “a bunch of junk”.

The boss of the US upmarket supermarket said: “We sell a bunch of junk. We’ve decided if Whole Foods doesn’t take a leadership role in educating people about a healthy diet, who the heck is going to do it?”

Staff at its London stores in High Street Kensington, Camden and Stoke Newington will be trained to advise customers on healthy eating and will themselves be “bribed” to lose weight.

They will be offered bigger discounts if the meet weight loss targets, stop smoking or reduce their blood pressure or cholesterol.

This week accounts filed at Companies House revealed that Whole Foods UK arm made a £35.9m loss last year.