Athens: Well-known British journalist Michael Mosley was missing on Thursday after taking a coastal walk alone on the Greek island of Symi, police officials said.

The TV doctor was last seen at 1.30pm local time on Wednesday (8.30pm AEST) when he set out on a short stroll along a path between Agios Nikolaos beach to the village of Pedi, one of the officials said.

British journalist and TV doctor Michael Mosley.

British journalist and TV doctor Michael Mosley.

His wife reported him missing on Thursday morning.

A search operation was launched by police, the coast guard and the fire brigade on the small island in the eastern Aegean Sea near Turkey, another official said.

Mosley, 67, is well-known for his 2013 book The Fast Diet, which he co-authored with journalist Mimi Spencer. The 5:2 diet, as it became known, set out how people can lose weight fast by minimising their calorie intake for two days in a week while eating healthily on the other five.

He has subsequently introduced the Fast 800 diet, a rapid weight loss program, whereby dieters restrict their calorie intake to 800 a day for at least two weeks, before transitioning to the 5:2 program.

Mosley has often pushed his body to extreme lengths to see the effects of his diets and also lived with tapeworms in his guts for six weeks for the BBC documentary Infested! Living With Parasites.

Mosley is also known for his regular appearances on British television, including the BBC series Trust Me, I’m a Doctor, as well as his column in the Daily Mail newspaper. He also appeared on the BBC’s The One Show and ITV’s This Morning.

In 2002, Mosley was nominated for an Emmy for his executive producer role on the BBC science documentary The Human Face, which was presented by Monty Python star John Cleese and which featured a raft of famous faces including Elizabeth Hurley, Pierce Brosnan and David Attenborough.