A viral diet that’s been found to burn up to 10 times as much fat as a standard diet is gaining momentum among Silicon Valley tech workers. And it involves eating a lot of fat.
The ketogenic, or “keto,” diet — which first became popular in the 1920s as a treatment for epilepsy and diabetes — limits carbohydrates to no more than 50 grams a day, which is the rough equivalent of a plain bagel or a cup of white rice. By comparison, dietary guidelines from the US Department of Agriculture recommend from 225 to 325 grams of carbs a day.
On the keto diet, the body goes into starvation mode and taps its fat stores for fuel. Studies suggest the low-carb, high-fat diet may promote weight loss, improve focus, and stave off age-related diseases. More research is needed on its long-term effects, especially among healthy people.
A small study recently published in the journal Diabetes and Metabolic Syndrome found that adults who had been diagnosed with metabolic syndrome (a precursor of diabetes) and ate a ketogenic diet had resting metabolic rates (a measure of how much energy your body burns when at rest) more than 10 times as high as people who ate a standard diet.
In 2017, I spent two months eating bacon, butter, and avocados to see why the keto movement is so popular with tech workers. Here’s what it was like.
I gave up breakfast for a week and drank this caffeinated meal-replacement shake instead »
The keto diet reorganizes the building blocks of the food pyramid.
It cuts down carbs to 20 to 50 grams a day, depending on a person’s medical history and insulin sensitivity. (There are about 30 grams in one apple or half of a plain bagel.)
On the diet, healthy fats should be about 80% of a person’s daily calories, while protein should be about 20%.
On average, Americans get about 50% of their calories from carbs, 30% from fat, and 15% from protein, according to the Centers for Disease Control and Prevention.
The human body breaks down carbohydrates into glucose, which is used for energy or stored as glycogen in liver and muscle tissue. But it has a plan-B fuel supply.
When carbs go missing from a person’s diet, the body uses up its glucose reserves and then breaks down stored fat into fatty acids, which, when they reach the liver, are converted into an organic substance called ketones. The brain and other organs feed on ketones in a process called ketosis, which gives the diet its name. Keto dieters eat lots of fat to maintain this state.
While the low-carb diet dates back to the 1920s, when it was found to reduce seizures in people living with epilepsy, Dr. Robert Atkins popularized a version of it in the ’60s and ’70s.
Like the keto diet, the Atkins diet restricts carb consumption to 20 to 25 grams a day during an introductory phase, but then ramps up to 80 to 100 grams a day. So it’s less strict than keto.
In 2014, Wali was moonlighting at a weight-loss clinic in San Francisco, where she saw her patients struggle to stick to their strict diet programs and maintain their weight loss. She started reading studies on low-carb diets and became convinced it was the solution.
Wali made herself a guinea pig before she prescribed the diet. And it worked.
She said she “expected to feel a lot of adverse side effects” from eating so much fat, “but what ended up happening was I felt great.”
“I started to have more energy and concentration,” Wali said. “I didn’t lose weight, but my fat distribution changed, so I lost weight from my hips.”
Tech workers living in the Bay Area sometimes go to extreme lengths to improve their bodies and minds. For example, at the supplements startup HVMN (formerly known as Nootrobox), most employees don’t eat on Tuesdays — a ritual they say improves ketone production and productivity. Intermittent fasting has been found to assist ketosis.
To see whether I was a good fit for the keto diet, Wali requested I have some lab work done, including a cholesterol panel and a fasting-insulin-level test. My results came back normal, meaning there was no medical necessity for me to go on the diet. If I were pre-diabetic or insulin-resistant, Wali would likely have made the keto diet part of my treatment.
We agreed that for my first week on the keto diet, I would aim for 30 to 50 grams of carbs during the day and eat regular, carb-heavy dinners, even if they took me over the limit.
“Sugar addiction is a real thing,” Wali told me in our first meeting. She wanted me to ease into ketosis to avoid “carbohydrate withdrawal,” which can cause irritability, depression, headaches, lethargy, and nausea. I was happy to take it slow.
As I was learning the carb loads of different foods in those first few weeks, I tracked my meals on the Fitbit and Weight Watchers apps, but Wali says paper and pen works just as well.
Fiber is a carbohydrate that the body can’t digest. It doesn’t raise blood-sugar levels, so there’s no use in counting grams of dietary fiber toward a daily carbohydrate goal.
A cup of almonds has about 20 grams of carbohydrates, but 12 of those come from dietary fiber. As a result, I had to count only 8 grams for the serving. What a bargain!
Some mornings I scrambled to find 20 minutes to make breakfast. Few restaurants had dishes that met my dietary restrictions. I ate a sad, tortilla-less breakfast burrito once.
I managed to find one restaurant, La Boulangerie in San Francisco, that makes scrambled eggs with mix-ins to order. I swapped potatoes for a side salad and tossed the toast. It cost $11.
I used to snack every hour between 10 a.m. and dinner. Food was always on my mind.
In my first week, I dug up the willpower to resist those sugar binges. But it was not without consequences. My headaches pounded for hours on end. My mind said, “Eat something.”
Wali recommended I drink more water and salt my food to ease the headaches.
Here’s the recipe for loaded cauliflower »
A doctor can prescribe a ketone-testing meter to people with diabetes, but insurance may not cover it. Optimizers like me turn to Amazon for third-party sellers.
I bought the Precision Xtra glucose-meter kit (which also measures ketones) for $22, and a 10-pack of ketone testing strips for $42. The meter has since gone up to about $60 on Amazon.
Keto adherents use ketone-testing meters to check whether they’re in a state of nutritional ketosis — generally considered to be above 0.3 millimoles per liter of blood, according to Wali.
Entrepreneurs sometimes share their ketone levels on social media. It’s the biohacking community’s equivalent of posting photos of a bathroom scale to celebrate recent weight loss.
Dr. Jason Fung, who specializes in kidney care, offers an analogy in his book “The Obesity Code.”
Imagine sitting down to an all-you-can-eat buffet. At some point, the idea of eating one more pork chop becomes sickening. But if the dessert cart passes, it’s hard to resist.
That’s because highly refined carb-filled foods, like cake and pie, don’t trigger hormones in the brain that say: “You’re full. Stop eating.” Proteins and fat can signal when you’ve had enough.
The worst part of cheating was that it had the potential to reverse a state of nutritional ketosis.
When my parents came to town over one weekend and I went rogue, I wound up with a ketone reading of 0.3 mmol/L, meaning my body was burning more carbs than fat.
I returned to the diet that Monday, but it takes an average of five days for the body to use up the leftover glycogen reserves and return to nutritional ketosis, Wali says.
By this point in my journey, most of the negative side effects had subsided. (I experienced leg cramps and tingling sensations in my feet, which Wali said was from eating too little salt. She suggested I try magnesium supplements, and the problem went away within days.)
A ketone reading of 0.9 mmol/L indicates a mild state of ketosis. Dieters can reach higher levels — “go deeper” into ketosis — by restricting carbs to fewer than 20 grams a day or fasting. But there isn’t consensus in the medical community that doing so unlocks additional benefits.
Geoff Woo, the cofounder and CEO of HVMN, said he aimed for 3.0 mmol/L or higher, which he achieves through intermittent fasts that spike ketone production, for “optimal mental flow.”
When I started to obsess over the numbers my ketone testing meter gave me, Wali encouraged me to instead focus on how I felt.
When I lost 30 pounds on Weight Watchers in college, I celebrated the numbers on the scale and how my clothes fit. But because I continued to eat carbs in smaller portions, I was still prone to sugar crashes and afternoon “brain fog.” The transformation was incomplete.
The keto diet made over my mind and my body. The sense of mental clarity and energy that came on about three to four weeks into eating keto was unlike anything I’ve experienced. I woke up feeling strong, confident, and capable of taking on whatever the day threw at me.
“This is how you’re supposed to feel as a human being,” Wali said during a follow-up visit.
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