Silicon Valley's favorite diet has techies eating lots of fat

Geoffrey Woo likes to start the day with a plate of eggs, cheese, and avocado. It might not sound like Woo, cofounder and CEO of "cognitive enhancement" supplements startup Nootrobox, is dieting.

But he subscribes to an increasingly popular diet - the ketosis, or "keto," diet - that he hopes will help him live longer and better. It has especially gained traction among Silicon Valley's biohackers, who often experiment with diet and medical devices in taking a DIY approach to biology.

The high-fat, low-carb diet turns the body into a fat-burning machine. When you turn off access to glucose, a primary fuel source derived from eating carbohydrates, the body taps into its own fat stores for energy.

See why health nuts from Silicon Valley to fashion runways are saying yes to fat.