The cafeteria at the Google campus near Venice Beach, in Los Angeles. More than 1,600 workers in Silicon Valley have joined a group called “WeFast”, whose members go without food for up to 60 hours

Obsessive technology workers are so serious about their work that they are giving up food to be more productive at the office.

A fad for extreme fasting has seized Silicon Valley in California. Followers say it is all in the name of being better employees.

More than 1,600 workers have joined a group called “WeFast”, whose members go without food for up to 60 hours at a time.

Employees at Nootrobox, a San Francisco company that sells nootropics — chemical compounds said to enhance cognitive function — stop eating on Monday nights. They forgo food for 36 hours and start eating together on Wednesday mornings.

Geoff Woo, the chief executive, said the fast had made Tuesdays “super productive” for the company and had led to