If you want to get into shape, you might decide to eat more vegetables and go to the gym more. But what if you want to have more energy, improve your mood, and sleep better? Welcome to “biohacking,” where practitioners use data about themselves and their environment to perfect their daily routine of eating, sleeping, working, and exercising for optimal performance.

Biohacking has been around for a while—and the success of the approach is still very much up for debate—but is now making its way into the workplace. Well, the Silicon Valley workplace, at least.

At Nootrobox, a San Francisco company that makes brain supplements, the entire company collectively fasts for 36 hours every week. “It was hard for the first couple of weeks, but now it’s like the company culture,” says co-founder Geoffrey Woo. “A weekly ritual if you will.” Some members of the nine-person company, all aged from mid-twenties to mid-thirties, even start early and do a 60-hour weekly fast.

Woo defines biohacking as treating your body like a computer system. “That means being experimental and rigorous about inputs in the system,” he says. “Measuring, quantifying and optimizing those inputs for specific outputs.”

Woo and his co-founder, Michael Brandt, have used data to solve larger problems since they met as computer science majors at Stanford. While in college, this took the form of Brandt using a journal to track all his conversations, in a bid to get better at talking to women. “It shows that mindset of being very rigorous, of measuring and quantifying one’s schedule to optimize for an outcome,” says Woo.

This same methodical approach is behind the company’s weekly staff fasts. And the method is working, says Woo—Tuesday fast days are “one of our most productive days of the week.”

Dave Asprey, 42, one of the first biohackers and an advocate for the practice, has spent $300,000 and two decades on hacking his own body and says he plans to live to 180 years old. He says there’s considerable interest among various Silicon Valley companies in the work produced by his biohacking company, Bulletproof. Yahoo’s CEO, Marissa Mayer, for example, invited him to speak to her company’s whole workforce, he says, and Yahoo owns a “Bulletproof Vibe,” a machine that vibrates the whole body and is intended to replicate some of the benefits of exercise.

Among Asprey’s own employees, executives use a heart rate variability sensor before big meetings to try to take themselves out of fight-or-flight mode. The result, Asprey says, is “we’ll have meetings that are more cooperative and creative.” He has also asked neuroscientists to hook his senior leadership team up with electrodes so they can monitor brainwaves and try to control their minds better.

“When you’re in control of your biology, you’re in control of your mind and you can make better decisions,” he says. “You’re actually a better person.”

Asprey’s employees regularly fast and, though he wouldn’t force the company to collectively fast—“that’d be incredibly odd and dysfunctional,”—he says he’d like to introduce an optional staff fasting day.

The downsides to tracking your body at work

Though there’s a great deal of excitement over biohacking, the idea of weekly staff fasts likely sounds a little daunting to all but the uber-committed. What if a friend invites you to a dinner party on fast Tuesday? If it’s your birthday and you’d like to bring in cake? Or if you have your period and just really want a piece of chocolate?

Until recently, Nootrobox didn’t have to worry about that last problem. The two co-founders and first six employees were all men, and the Nootrobox only hired its first woman this month.

Inevitably, there are ethical and human resources concerns that come with staff fasting, and some of them are gender-related. Even if a fast is optional, employees may feel pressured to take part. If they can’t, perhaps because of an illness or pregnancy, the employee could be forced to reveal private medical information to the employer.

Asprey also says that fasting is “definitely” not a good idea for people with eating disorders—which tend to affect women more than men. And of course, he says, “there are certain times of the month for women when fasting is much harder.”

There are also questions about whether it’s even right for bosses to see exactly what makes employees stressed or unhappy, and how employers could use health data about their staff.

Brandon Smith, a therapist who focuses on workplace culture, says measuring employees’ heart rates and brain waves raises serious questions. “Will it be used in assessing people’s performance and determining rewards and promotions?” he asks. “For example, ‘Brad clearly handles pressure better than Sanchit. Look at his brain waves.’ Unless this practice is purely voluntary and the data can only be accessed by the participating employee, it is a dangerous idea to implement.”

Smith says biohacking can be a valuable tool for self-discovery, and a means for employees to gain greater self-awareness and control over their emotions. But it should not go further than that.

“When biohacking becomes a tool used by the organization to control and manipulate employees’ emotions, moods and physical reactions to various situations, the company has crossed an ethical line,” he says. “Our journey as human beings is one of self-discovery. To that end, biohacking can be a value. Beyond that, it is a damaging Orwellian control tactic.”

Asprey acknowledges that there can be downsides to biohacking, but that “there’s a much bigger downside to ignoring your environment and letting it tell your biology to get weak and die after you’re too old to have kids.”

For his part, Woo admits that biohacking and staff fasts are a rather specific taste. “Everyone can benefit from the work we’re doing at Nootrobox, but not everyone should work at Nootrobox,” he says. Given the nature of the company’s work, it attracts employees who are already involved or interested in biohacking, he says.

“It’s not a job requirement to fast or biohack but it’s an activity that predicates why we exist as an organization,” he says. “We think biohacking can help people become better versions of themselves, and in turn create a better, more productive society.”