Employees at this Silicon Valley startup don't eat on Tuesdays

Free food and startups typically go hand-in-hand, but at Nootrobox, a smart drug company, their team bonding takes a different form: Fasting.

In a profile in the San Jose Mercury News, Nootrobox cofounder Greg Woo said his company has become "super productive" on Tuesdays because no one eats.

The fasting isn't meant to curtail lunch costs for employees, but to super-charge their brains. As a so-called "smart drug" company, Nootrobox specializes in creating nootropics designed to improve brain performance and gummy caffeine cubes to help people get an extra boost throughout the day.

It's all part of a larger movement towards "biohacking," or a movement in Silicon Valley in which people experiment with various supplements or devices that they believe lead to increased productivity, mental acuity, and other benefits. Some use supplements, like the kind Nootrobox manufactures, but others, like well-known biohacker Dave Asprey, mix butter into coffee.

Those who fast, like the four employees of Nootrobox, are trying to reach a state of ketosis, where the body starts burning fat for fuel. They each fast between 24 to 36 hours (or a dinner only diet), but it all culminates in a breakfast with other biohackers on Wednesday mornings.

"It's hard at first, but we literally adopted it as part of the company culture," Woo told the Mercury News.