In late December, Kevin Rose took to Medium to announce he created Zero, a new iPhone app to help you fast. It pushed a particular breed of fasting known as “intermittent fasting," which demands people fast for 16 hours a day beginning at sunset. The iPhone app, which is free, has a slick, smooth user experience, with a balming palette of fuchsia and orange hues.
Rose is a prince of Silicon Valley, best known for being one of the original co-founders of Digg. He began dabbling in intermittent fasting a few years ago, crediting its popularity with Hugh Jackman's endorsement. Jackman went on 60 Minutes four years ago to talk about his role as Wolverine and his journey to a lean body. Rose, after hearing of Jackman’s flirtation with intermittent fasting, played with it “just out of curiosity," motivated by an interest in how far he could push his own body. Rose doesn’t know much about the history of intermittent fasting, though one of the doctors whose work he cites, University of Southern California’s Valter D. Longo, told me over email that intermittent fasting has its roots in rat experiments of the 1950s, though it’s now become particularly popular among Silicon Valley’s elite.
He began tracking his fasting using a Google spreadsheet, where he jotted down start and end times for his daily fasts. He couldn't find an organized way to do this, though. Rose knew there were a ton of built-in timers on smartphones, of course, but he wanted a way to synthesize these elements for the intermittent fasters of the world. So he built Zero.
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“We are just making this for all the little biohackers in the community,” he explains. So, how many itty bitty biohackers are there? Rose tells me he’s gotten about 30,000 downloads as of last week, and is still getting a little over 300 downloads per day. He has seen about 7,000 active fasts per day.
When I ask him about his diet, Rose describes it in mathematical terms: 90% of his time is just spent eating “a pretty well-balanced diet with a focus on fruits and vegetables,” he says. The remaining 10% of the year involves “trying out different protocols based on what sounds interesting just to see how it affects my brain function or waistline.” He did 10weeks of ice training, submerging himself in ice water up to his neck at 15 minutes at a time. "You get some amazing energy during that type of protocol," he tells me. He's tried a ketogenic diet, which he describes as "magical." He's worn a continuous glucose monitor that he sticks into his thigh, syncing it up with his iPhone and Apple Watch.
"I can eat a piece of fruit and then hold up my Apple Watch to see what my glucose levels are," he says of this aspirational lifestyle. "I just try a ton of crazy, fun little body hacks. I’ve always considered myself a pretty curious person.”
Body hacks. Magic. Curiosity. What a world! The release of the app attracted a flurry of gentle criticism, along with more than a few eye rolls. "If you like to laugh at men being ridiculous, here's a thread." one person claimed. “This is the most Silicon Valley shit,” another said. Others wondered why such prominent figures of Silicon Valley, land of the bountiful capital, would use their minds to create an app to better their own lives when there were others, especially those who were starving, in need.
Rose becomes defensive when I bring this line of argumentation up. “When I see those types of comments, I just know that person hasn’t read the data," he says. "Because if they had, they’d understand the seriousness of intermittent fasting, or the science behind it. I think that, when you actually look at the data, and how it’s helping people who go into remission for cancer and lowers the reoccurrence rate, you realize intermittent fasting is not a joke.” (There were some qualms with Rose’s conflation of causation with correlation.)
Rose links this knee-jerk criticism to a lack of solid mainstream understanding of fasting’s benefits. “If you think of fasting as just a way to starve yourself and you’re not aware of the published studies in peer-reviewed journals, you might just see it as something that’s cosmetic and purely done for weight-loss purposes,” he claims. To rectify this with Zero, he built a “Science” tab in the upper right-hand corner of the app that links to research. He, too, was mindful of not mentioning weight loss anywhere in the copy for the app or its marketing collateral.
Other critiques, though, he gave more credence to. Among the most trenchant initial critiques, though, was whether Rose consulted any Muslims as he created this app, and whether he designed the app for them at all. Millions of Muslims fast each year, after all; so do Jews and Jains. Ramadan-focused apps do exist already, but they aren’t widely-known, and haven’t gotten endorsement from men of Rose’s stature and following in the universe of the Bay Area.
“I didn’t have a chance to talk to that individual,” Rose says of one person who responded to his tweet. “I did get a couple of emails about it as well. If there was a simple little tweak for the app to make it compatible with their regimen around that, that’d be great.”
So far, though, that push hasn’t weighed on Rose, and the app exists as is. Rose is insistent on the fact Zero is not a venture-backed business, just a weekend project he and two other team members work on part-time. The implication here is that Rose doesn’t have an obligation to placate his critics. The app's last update was two days ago, with added push notifications, an option to change your start time for fasts before you stop fasting, and the small bug fixes. For now, it's just an app meant for him and his fellow body-hackers, wherever they may be.
Zero is available for download on iOS here. Have any experience with intermittent fasting? Let us know in the comments.
Mayukh Sen is a James Beard Award-winning food and culture writer in New York. His writing has appeared in the New York Times, the New Yorker, Bon Appetit, and elsewhere. He won a 2018 James Beard Award in Journalism for his profile of Princess Pamela published on Food52.
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