Members of a small New York subculture seek good health through a selective return to the habits of their palaeolithic ancestors. Or as they describe themselves, they are cavemen.
The caveman lifestyle involves eating large quantities of meat and then fasting between meals to approximate the lean times that his distant ancestors faced between hunts. Vegetables and fruit are fine but the modern-day caveman avoids foods such as bread that were unavailable before the invention of agriculture. Instead of eating three square meals a day, many of New York's cavemen fast intermittently, up to 36 hours at a stretch.
John Durant, 26, who works in online advertising, believes the human body evolved for a hunter-gatherer lifestyle and his goal is to wean himself off what he sees as many millennia of bad habits.
These urban cavemen also choose exercise routines focused on sprinting and jumping, to replicate how a prehistoric person might have fled from a mastodon. The tribe is not indigenous to New York. Several followers of the lifestyle took up the practice after researching health concerns online and discovering descriptions of so-called palaeolithic diets and exercise programmes followed by people around the country and in Europe.
Melissa McEwen, 23, was searching for a treatment for stomach troubles. She started reading the blog of a 72-year-old retired professor who lives in Utah, Arthur De Vany.
De Vany's blog promotes what he calls "evolutionary fitness". Like his disciples in New York, he believes that ancient humans could perform physical feats that would awe the gym rats of today.
Loren Cordain, a professor at Colorado State University and the author of The Paleo Diet, links the movement to a 1985 New England Journal of Medicine article, which proclaimed that the "diet of our remote ancestors may be a reference standard for modern human nutrition".
