Dan Benjamin is an entrepreneur whose business is at the cutting edge of the US’s technology and online media industries. Yet when he began experiencing a host of unexplained allergies, high cholesterol and hypoglycaemia, he ignored his doctor’s advice and put his family on a diet likely to have been eaten by his hunter-gatherer ancestors 100,000 years ago.

Mr Benjamin, the founder of 5by5, a producer of internet broadcasts, had just gone Paleo. The Paleolithic diet – lots of lean meat and animal fat, no grains such as bread and pasta, or dairy products – has taken Silicon Valley workers by storm. Pizza is out at all-night strategy sessions; grass-fed beef is in. “The Paleo diet is huge among tech people,” he says. “Early adopting is one part of it, but there’s probably an epidemic of bad eating among tech people who are working long hours, have sedentary jobs and are eating mainly pizza and fast food.”

He adds that it is much more than a passing phase. “I know it’s seen by many people as a fad diet but it wasn’t a fad diet for the thousands of years before we invested in agriculture and started having the modern problems we have today. I know that after switching to this diet, the medical problems I had were gone.”