The ex-CEO of Evernote says Silicon Valley’s favorite fasting diet has changed his life — here’s his routine

Phil Libin

Phil Libin, the ex-CEO of Evernote, doesn't eat for two to eight days in a row.
He subscribes to an increasingly popular diet called intermittent fasting, which has a host of benefits backed by science.
Tech executives say fasting gives them a mental edge in Silicon Valley.

Phil Libin, who helped create the popular productivity app Evernote in 2007 and led the company as CEO until 2015, was melancholy for a long time. His work didn't excite him.

Eventually he pinpointed the source. "It was the carbs," he said.

The fall of 2017 marks the one-year anniversary since Libin, who now runs an artificial intelligence startup studio called All Turtles, started fasting on a regular basis. The tech executive foregoes food for between two to eight days in a row every week, drinking only water, coffee, and tea.

Libin has lost 85 pounds, reversed a prediabetes diagnosis, and feels "25 years younger," he told Business Insider in a recent interview at the All Turtles office in San Francisco.

Intermittent fasting is an increasingly trendy diet that involves going without food for anywhere from 14 hours to several days. Strange as it sounds, the diet has a lot of scientific backing. Large studies have found it to be just as reliable for weight loss as traditional diets. Some studies in animals have suggested it could have other perks as well, including reducing the risk of certain cancers, improving cognitive performance, and even prolonging life.

The fad has picked up fans in Silicon Valley, including author and podcaster Tim Ferriss, Y Combinator partner Daniel Gross, internet entrepreneur Kevin Rose (who created an app that lets fasters track their progress), and nearly the entire team at "smart drug" startup HVMN.

phil libin evernote

In November 2016, Libin found himself in a rut. He was working as a venture capitalist at General Catalyst while trying to come up with his next idea for a game-changing startup. He moved from New York to San Francisco while dealing with divorce after 19 years of marriage.

Loïc Le Meur, a friend and fellow entrepreneur, told him about a new diet that made him feel great. He hadn't eaten in three days. Libin thought it sounded "really stupid."

"I went home [after meeting with Le Meur] to Google it, with the intention of just like, proving to him that he was being an idiot and needs to eat", Libin said. "I was really surprised after reading about it for a few hours that it all felt really plausible."

With the countdown to his 45th birthday ticking, Libin decided to try a three-day fast. On the first day, he was hungry. The second day proved harder. On the third day, he felt amazing.

"It was a little difficult in the beginning — but difficult compared to what? Even the first day was easier than spending an hour at the gym," Libin said. "I woke up on the third day and I felt better than I had in years. I was hooked on it right away."

Libin now fasts for two to eight days straight, depending on his work schedule and personal life. A business trip to Japan, where Libin can't say no to ramen, or New York, where the pizza is divine, warrants an "eating day." So does a meal with an old friend in town.

On days he fasts, Libin drinks copious amounts of water, coffee, and tea. He rarely cheats on the diet, because he knows he won't be able to stop eating once he's started.

Other days, he indulges, but not overly so. Libin typically skips breakfast because he "prefers sleeping." He enjoys his favorite meals at some of the top restaurants in San Francisco, including the farm-to-table fare at Cockscomb and yakitori (a Japanese-style skewered chicken) at Rintaro. There is no calorie-counting or strict dieting on these days.

Libin returned to his doctor for testing and blood work earlier this year and found that he had reversed his likelihood of developing type 2 diabetes. He's maintained his goal weight for at least three months.

Phil Libin headshot

At work, he describes feeling happier and more focused. He's rarely hungry. There are no midday sugar crashes, because there are no snack binges. His meals, which are nearly always shared with business colleagues or friends and family, are documented on his calendar.

"Eating nothing is [working out] really great for me. You don't have to think about it. I get back all this time, and I just don't eat anything," Libin said.

Libin plans to continue eating — and not eating — this way for the rest of his life.

"This is easily in the top three most important things in my life that I've ever done. It's absolutely transformative," Libin said. "And, look, check back in a year. I feel like I'm going to stick with it, because I really like it. I've dieted before, but I always thought the diet that I was doing wasn't fun. I didn't enjoy it. It got harder and harder.

"I'm not fasting to lose weight anymore. I'm fasting because I really like it," he added.

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