How Fasting Turned Into Silicon Valley's Latest Obsession

you up on a bunch of calories. So this is instead of having a real breakfast. Now you get to have breakfast too. They feed you these breakfast bars and they're actually pretty tasty nuts, honey, coconut. But yes, far fewer calories than you would expect. It's not gonna kill me. Yeah, go for it. What does it smell like, No, it's it's yeah, it's like this. It smells like a cherry

Nike will would is not a bad thing. Over the last five months or so, I've tried all kinds of fasts, thirty six hours, three day, five day fast that mimic the effects of a fast. Yeah, time I've watched it with equal amounts of admiration, horror, and the concern of a Jewish parent, as has just about everyone else around me. So I've heard about the Silicon Valley obsession with fasting. Is it just about losing weight? For some people, it's

about wanting to lose weight and be healthier. For other people, it's a productivity hack to work faster, to focus better. And what about you? What made you want to try it? I definitely wanted to see if I could get those benefits too. There was also a religious component to it. This fell during Lent, when a lot of people fast, but as a tech journalist, I was just curious. Fasting has become this huge trend in text circles, and I wanted to understand why. So I joined forces with our

colleagues Selina Wang to help with additional report name. Hi, I'm Brad Stone, I'm Tom Giles, and I'm Selena Wayne. And this week on Decrypted, we're taking a look at Silicon Valley's latest obsession, intermittent fasting, from young entrepreneurs to establish executives. Fasting has become a fixture in the tech community, and like a lot of other fads that catch on in Silicon Valley. All kinds of startups are emerging to

make a business out of it. So today you're gonna be meeting some of these enthusiasts and businesses and we'll be asking are the supposed benefits real or is this under indulgence simply another form of over indulgence here in Silicon Valley? Stay with us. So people have been fasting since time immemorial, but the kind of fast thing we're

talking about today is pretty specific, that's right. And there are a lot of different iterations of it, every thing from skipping a few meals a few times a week to these water only fast that go on for days. Of course, before I started any of them, I went to see my doctor to talk about it. And what did your doctor say? My doctor had no reservations. His take, go for it. I started small. I did twenty hour

fast three days a week. You're essentially skipping breakfast and lunch and confining your eating window to about four hours in the afternoon evening. It's known as the Warrior fast for the good stress it puts on your body. Okay, and how did that go for you? Well, in the beginning, I'd get really hungry on my fasting days, and i'd get a little testy in the afternoons. Let me read you a journal entry from about three weeks in. I am so damn hungry, counting the hours until I can

start eating again. Someone a few rows over was eating an onion begel and I couldn't see it, but I could recognize the aroma instantly. That sounds pretty dark. I didn't know that we were counting you whether afternoons next. I also tried fasting for thirty six hours at a time, but I really gravitated towards an approach that would let me have dinner with my family each night. But I also remember you going on some longer fasts right. One especially intense one was a three day water only. Okay,

that sounds very brutal. I recorded a voice diary for that one. I definitely feel hunger. It's clear to me that I was thinking about food as I slept last night, because I remembered a dream where I was at a gathering and there were piles of bread and a mountain of garlic bread, and then there were stacks of Pizzas.

My wife is out of pocket, and so it's my turn to do dinner tonight, and I will definitely be tempted, but I am confident I will resist, and I might even go downstairs and have a little bit of a workout in our home, Jim. Right now, I am feeling very focused, very energetic. I had a very productive day. You know, you actually sound surprisingly upbeat. You know, I got used to it. Probably the hardest one I did was a five day fast that you heard me try at the top of the show, of the one where

you were allowed a very limited number of calories. That's right. You get about eleven calories on the first day and then eight hundred on each of the four following days. You can't work out on this one, and by days four and five I was feeling especially tired. I also just missed the variety of a normal diet. As I tried more of these fasts, Selena and I went to go meet someone who's had a lot of success with it. Hi, Hie.

This is Sumaya Kazi today. She has this kind of cult status within the fasting community ever since she wrote this medium post about her fasting lifestyle that went viral just a few years ago. Samaya was running a start up and she was pulling long days and nights, just like a lot of other entrepreneurs in Silicon Valley. At a certain point, she really reached her breaking point. Seven years of building a company is probably the worst thing

you can do for your health. It is so difficult on your body, with the stress, the lack of sleep, the late nights, the eating bat I had high blood pressure, I had issues with sleep apnea, I was pre diabetic, and I was obese. She tried exercising, she tried all kinds of diets, but the thing that finally worked for her was fasting. She's lost fifty pounds, ten point five percent body fat, and forty around her body, and she's

kept it up. I fast Monday's, Wednesday's, Friday's, I have coffee of water, sparkling water, have tea, I go to bed. It's actually such a relief to not have to think about your next meal half the week. Over the years, she's seen a lot of other people take up fasting too. There's been such a cultural shift, at least in my own community, where more people are fasting than not. Throughout our reporting process, one of the big questions I've had

is why is this so appealing to people? In Silicon Valley. We asked, Sumya, I feel like that's really appealing in the Silicon Valley and startup community, because again, you're working really really long days, and anything that can help you be feel more productive, more focused, UM, reduced your decision making that you need to do UM and make you feel good is something that people kind of strive for in this community. So did so MAYA have any tips

for you? Tom? I gotta say her story is pretty inspiring, and it's really no wonder that she's gotten her colleagues and friends and family to take up fasting. So from her, I adopted her three times a week approach, even though I'm nowhere near as hardcore. A lot of fasters also call themselves bio hackers. They think of themselves as hacking their own biology. I visited an entrepreneur in his thirties here in the Bay Area who takes this a lot further than someone like Sumaya. He takes it to the

very extreme, taking all of these pills every morning. And then those went about those pills. I take them every morning as well, so I just measure them out more carefully because this is search forgett He's an intermittent faster too. He typically eats only one meal a day in the later afternoon, but he actually does a lot more than that. He fasts and takes about forty pills a day to have what he says is better energy, mood, focus, confidence, sleep, willpower,

and longevity. Okay, alright, one last round, one more handful. Yeah, I'm not sure. So some of the pill search takes our things. You and I might take vitamins and supplements that are over the counter, like fish oil, garlic, and tumeric. But he takes it a step further with prescription meds and working with a team of medical experts, including Peter A. Tia, a well known doctor in the space. So the stuff

is this is um, These are basically thyroid hormones. This is medaphanel, which is like UM intelligence enhancer that a lot of college students use. And I take style prom, which is an antidepressant. Wow, this seems very serious. I'm glad he has a team of doctors looking over him. Yeah. I was definitely surprised to walk into his bathroom and see these prescription meds everywhere. But on top of that, he also tracks his blood work, hormones, sugar, levels and

insulin resistance. Tom, you never went this far right? Oh no, nowhere close. I had my blood tested a few times, and I tested other things from time to time, but nothing quite this quantified search has an interesting philosophy. He runs this AI startup called Mirror AI, and he likens humans to robots. He says, there's no reason why we can't just engineer ourselves to live longer and work better.

I would just keep asking myself, Okay, what else can we do that's safe, that on my medical team will help me with, and that will give me more benefits in terms of just better cognitive ability, better ability to perform my tasks. So originally the started as an interesting longevity but now it's more about enhancing my performance, enhancing my competitiveness relative to other people. You can really hear the engineer's mindset here. It's almost like Serge is testing

new software or something. Yeah, that's a good way to put it. I mean, to most people his regimen will sound nuts, but to Sarge, it's a no brainer. So look and Valley is um competitive community full of very smart people. And when you're a smart person in a competitive group of smart people, you keep looking for advance. Interesting. You kind of arrive at this conclusion that you know your health is a competitive advantage tool. It's really stupid

not to focus on optimizing your health. It's just you instantly become uncompetitive compared with people who do this. Underlying all this enthusiasm about fasting is at least some science, like the work of Professor Walter Longo. Selena and I had the chance to visit his lab at the University of Southern California. We walked into this building with several large room filled with row after row of mice stacked in columns. We started in the hallway. Yes, yes, petive gear,

protective gear. Is this to protect our bacteria from the right, to protect the mice from us? Yeah, exactly, We're not going to catch anything. Walter has been researching calorie restriction and fasting for decades. They were about more than a thousand mice in his lab, and they were all on these various fast mimicking diets. The moment we stepped inside, we were hit with this waft of a very pungent animal smell, like when you walk into a pet store.

It's all very counterintuitive. The idea that eating less can produce more energy and a longer life. So what did his research find. It's shown a number of things. First that mice on fasting diets live longer and perform better at tasks. It's also shown that fasting and mice starves cancer cells and helps chemotherapy drugs more effectively kill cancer. And a very low calorie diet can slow multiple sclerosis by killing off bad cells and generating new ones. Fasting

exploding the bodies evolved ability to do his job. That's extremely powerful, more powerful than almost anything that you can imagine in man along. So for maximum anti aging effects and cellver generation, Walter advocates for longer but slightly less strict fasts. So he's created this company. It's called l Neutra, and it's commercialized. This five day diet that he recommends.

The diets called pro Lawn comes in a box with five days of food, everything that you need for that period, soups, drink mixes, breakfast bars, even some desserts, but at a severely reduced calorie intake. So this is the delicious concoction we heard you mixing at the start of the show. That's right, and you're consuming so few calories that you supposedly get the benefits of fasting, because Walter says it's

not a good idea. To eat absolutely nothing for five days is dangerous because it can cause hypoglycemia, is dangerous cause hypotension. For our non doctor listeners, Hypoglycemia is what happens when your blood sugar is too low, and extreme cases, it can result in confuse, Usian seizures, a loss of consciousness, and then hypo tension is overly low blood pressure and it can be life threatening. Walter's company is backed by

millions of dollars in government and private funding. We should also note that it costs two dollars for the five day regimen. That's a little expensive because you know, eating less is pretty inexpensive. Yeah, but if you think about it, it's all the food that you need for five days. There's also a consultation with the nutritionists in the mix, and more than forty five thousand people have subjected themselves

to this regiment. The company works with thousands of physicians that use the meal Plan as a way to treat people with metabolic issues related to increased weight, high blood pressure, high cholesterol, and insulin resistance. Walter says His science boils down to this, you're essentially tricking your body into going into starvation mode that breaks down and regenerates the inside

of cells, killing off and replacing aged one. And of course I use always the analogy of a wood burning train, right, and so now imagine you running out of fuel. You've got to get to the next train station, and the engineer starts looking around the train for wood that it can burn. Of course, you wouldn't want to take the good one. The chairs that are are the walls that are in good shape. Take the bad one first, right, So take a part of their chairs that are broken, etcetera.

Use it for a feel. Now the train becomes lighter and you eat yourself for a few So that's one way to make a business out of fasting, by making these kids that help people get the benefits of starvation without actually starving to death themselves. Another interesting business model is one that a startup called plate Joy is doing. The company puts you on these personalized nutrition plans. It's

CEO is Christina Bognet. We get paid by insurance companies when people lose weight, and so as a company we had to do a lot of thinking around it. Was actually going to help people lose weight, and we know that most diets fail and that most people it's very hard for most people to lose weight long term. Christina herself lost a lot of weight from fasting, and Plajoy teaches its pre diabetes customers had fast We suggest is that you try sixty hour fasts every day for two weeks,

see how it goes. Report back. We'll know how it's going because we're looking at the data as well. And what I love about it is that the results tend to be quick. This particular program rolled out at the end of February, so we're hearing from people who have said, I have not been able to get my weight to budge. I'm done seven pounds of two weeks. This is incredible, this is life changing. One person said, I could cry with gratitude. This is exactly what I needed. So that's interesting.

One day your insurance provider could even pay you for all the weight you've lost. Yeah, you kind of get the appeal to an insurance provider given all the health problems that are associated with obesity. So I think I'm still pretty skeptical about this absolutely. I mean, there is still a lot of disagreement in the medical and scientific community over the benefits of fasting. For example, Valter Longo the scientists says daily fast more than twelve hours can

lead to an increased risk in golf stone formation. Some physicians say there's just not enough data that shows the long term effects of fasting methods and humans. They've tested it in things like yeast and mice, right, and what works for mice might not necessarily be that great for humans. And another concern of some doctors is how could this potentially lead to another eating disorder or be a precursor to one. Okay, so lots of caveats and risks to this,

even with some promising science. Tom, how did your experience turn out well? At the risk of sounding like a fanboy, I definitely reaped some positive benefits. First of all, I lost about twenty pounds over five months um. I definitely saw a reduction in my cholesterol levels. I was able to test for catosis, which is basically that stage where where your body is using it's fat for energy instead

of glycogen um. On days of fasting, I really did feel like I had higher mental clarity, higher productivity, and supposedly this results in stem cell regeneration, but that's a lot harder to measure. So, Selena, you tried Walter Longo's five day fast? How did that go? So? I'm sort of a serial snacker, so it was very difficult for me. I almost broke the fast multiple times, but I stuck with it. Day three was definitely the worst. It was hard for me to focus because I was so hungry. Interestingly,

day five was the easiest for me. I wasn't that hungry. I felt light and sort of energetic, like I could go for days without eating. But on the sixth day, happily eight. Well, I saw both of you guys doing it, and I just have to remark on how much discipline it required, and I was admired it quite a bit. But why do you guys think that intermittent fasting has captured the spirit of Silicon Valley? Why has this trend

started here? Kevin Rose, for example, the entrepreneur who found a dig He talked about how it's part of this quantified self movement where people just love to track all these all these metrics about themselves. They have these elaborate spreadsheets, and it's really sort of this obsession with optimization and enhancing her own self competitiveness. Yeah, that reminds me of Phil Libbon. We've all read about his story where this guy lost sixty pounds over the course of several months

through intermittent fasting. He's a total true believer. He says it makes him happier, more more productive, mentally sharper. He talked about how if he's got an important meaning coming up, um, he'll try to you know, he'll try to fast for two or three days in the run up to it. But even he is able to look at this with

some degree of skepticism. He also says it's kind of like appealing to the worst instincts of us in Silicon Valley, people who want to feel smug and SUPERI year to everyone else like we found this secret, we found this hack. It's also really a luxury, as you said, to be able to fast. It's ironically sort of for the elites. Version of over indulging is not indulging at all. And when I spoke to Sarah, she was very open about it. He said it costs him about two hundred thousand dollars

out of pocket to get all the prescription meds. See all of these specialists, doctors. This isn't cheap. What is the risk that this trend pushes people to start behaving or eating unhealthily. Well, I spoke to the director of the Eating Disorder National Program, and she said that any type of diet can lead to eating disorders, especially one like fasting, where you sort of get into this reward cycle where you feel like you really accomplished something by

not eating. You see the weight loss, So there's definitely a risk there. This is This is why I think it's really important. And everyone again we talked to said this is you got to do it in consultation with your doctor, with a medical expert. Admittedly weird people who have the advantage of, you know, great health care and access to physicians. Not everyone does, but certainly anybody who's going to embark on something like this needs to be

in contact with a physician. And bottom line, this is difficult, expensive and non intuitive. So right now, it's makes sense that it's really concentrated in Silicon Valley, where there's a sort of engineering mindset. So, Tom, fasting, is this phenomenon here in Silicon Valley? Uh? Considering though that it is expensive,

considering that you need medical oversight. Uh, considering that eating three meals a day and snacking is something of its own religion elsewhere in the country, can this spread outside of tech? Yeah, you're right. There is a lot of reasons why this appeals here. And it's very convenient and something of a luxury for people who live in cities

like San Francisco, New York City. Plus there's a huge economic incentive for the food industry to get us to buy into this idea that we have to have breakfast, we have to have snacks, we have to have three plus meals a day. So there's a lot of reasons why. Uh, it's it's unlikely to spread. Having said that, there is a there are a lot of people. There's a growing number of people who are spreading this religion of I just feel better and this is more effective than anything

I've tried. We've talked to so many people who say they did everything, they tried, every dieting fad, you name it, um and this is the only thing that worked for them. So, if you look at it across this country and there is an obesity epidemic, if people can find something that's gonna let them in a healthy way, lose weight and feel better. I think that resonates. And that's it for this week's episode of Decryptic. Thanks for listening. What do

you think of today's show? Email us at decrypted at bloomberg dot net or reach out to us on Twitter. I'm at at ts Giles, and I'm at Selena Underscore Why Underscore Way, then I'm at Bradston. If you haven't already, please subscribe to our show wherever you get your podcast, and leave us a rating and a review. This episode was produced by Akido Piaget Kari, Liz Smith, Magnus Hendrickson and Tofur Foreheads. A special thanks to Daniel Gross from

y Combinator, Jeffrey Woo of Human and Peter Atia. Francesco Leady is the head of Bloomberg Podcast. We'll see you next week.