The Silicon Valley execs who don't eat for days: 'It's not dieting, it's biohacking'

Techies are pushing the trend of intermittent fasting for weight loss – made popular by diets like the 5:2 plan – to the extreme. Are they crazy? The last time any food passed Phil Libin’s lips was a day ago, when he ate yakitori at a restaurant in San Francisco’s Mission district. He’ll next eat in three days time on Thursday evening, when he has a reservation at one of the fanciest sushi restaurants in town. In the intervening four days it’s just water, coff