Silicon Valley's favorite high-fat diet is beloved by everyone from venture capitalists to LeBron James - here's how it works
- The keto diet is one of the trendiest diets around, but it was originally developed to help children with epilepsy suffer fewer seizures.
- It kicks the body into a natural fat-burning mode, called ketosis, by starving a person's system of carbs and sugars, which are typically the first fuels we burn.
- Some people say being in ketosis helps them focus and decreases their appetite, while trimming belly fat.
- Anyone who wants to try going keto should consult their physician first.
- More research is needed on the long-term effects of the high-fat diet for the general public.
Dieters from Silicon Valley to the Hollywood hills are convinced the trendy keto diet is nature's miracle plan for the body and the brain.
The high-fat regimen has become the go-to eating plan for celebrities like Halle Berry and the Kardashians, Silicon Valley tech workers, venture capitalists, and sports stars like LeBron James. Fans of the diet believe it can burn off belly fat, tamp down hunger, and increase energy, all while allowing them to gobble up more fatty and oily foods.
The diet relies on a natural fat-burning state called ketosis. It's the same process that happens automatically when people starve.
In ketosis, the body switches from its default mode - burning carbs and sugars for fuel first - and begins forcing itself into breaking down fatty acids for functioning. Entering ketosis usually takes at least a few days.
Doctor Priyanka Wali previously told Business Insider that most people use up leftover glycogen stores in about five days, and experts agree it takes at least one to three months to see and feel all the benefits of the restrictive plan.
The keto diet wasn't originally developed for weight loss. Physicians started prescribing the diet in the 1920s to help with tough-to-control epileptic seizures that weren't responsive to other drugs. The diet can significantly reduce the instance of seizures in children, and in some cases, stops them completely. It can also help control blood glucose levels in adults with Type 2 diabetes.
Many keto fans who don't have epilepsy or diabetes report feeling sharper and more energetic on the diet. Some competitive athletes are also convinced that following a keto plan also helps them perform. Ultra-marathoner Zach Bitter, the world record holder for the longest distance run in 12 hours, says going keto most of the time helps him speed into record-breaking athletic performances.
The US military's Defense Advanced Research Projects Agency (DARPA) also poured $10 million into developing a ketone ester drink that generates energy from ketones, hoping to one day give its soldiers on the battlefield an extra edge both physically and mentally. The drink is on the market now for performance athletes.
But research on the keto diet for athletes is still mixed: some studies suggest that relying on fat can actually hurt an athlete's performance. Large-scale studies are needed to know for sure.
Keto by the numbers
One of the trickiest things about the keto diet is all the careful counting it requires.
Dietitian Kristin Kirkpatrick at the Cleveland Clinic suggests people going keto should aim to get 70% to 80% of their calories from fat, with less than 10% from carbohydrates. To that end, most keto dieters try to keep daily carb intake between 20 to 50 grams.
Considering there are roughly six grams of carbohydrates in a single medium-sized carrot or a serving of unsweetened Greek yogurt, keto meal planning requires a hefty dose of forethought. It's not as simple as swapping a slice of morning toast for a few strips of bacon.
Since going keto can get complicated in a hurry, one Redditor even created a handy keto food pyramid that he encourages people on the keto diet to print out and put on their fridge.
Here's what's safe to include on a keto diet
- Meat (pretty much any kind, including poultry and red meat.)
- Fish.
- Leafy greens.
- Eggs, including the cholesterol-rich yolks.
- Cheese.
- Oils, especially those containing healthy mono and polyunsaturated fats (like olive oil). This is critical because relying too much on more saturated fats from dairy and meat can cause digestion issues and hurt your heart.
- Avocados, another great source of monounsaturated fats.
- Nuts and seeds.
- Cauliflower is a keto-friendly veggie that is low in carbs and high in dietary fiber. Many keto dieters use it as a substitute for bread, pasta, and crusts.
- Berries, especially blackberries and raspberries.
- Heavy cream.
- Lots of water and other unsweetened drinks to stay hydrated. Tea and coffee are both fine.
- There might even be a place for dark chocolate on the keto diet. Most people suggest sticking to cacao concentrations higher than 70% to 80%. Lower concentrations are too carb-loaded.
What to avoid on the keto diet
- Sugar. (Duh. This is all carbs.)
- Other carbohydrates like bread, pasta, rice, potatoes, and wheat-based flour. (There's one big caveat to this rule, however, which we'll dive into below.)
- Anything made with corn, especially high fructose corn syrup and other sweeteners.
- Legumes like chickpeas and beans of all kinds. These nutrient-rich foods are high in belly-filling protein and fiber, but the idea with ketosis is to rely more on fat for fuel. Many keto dieters limit their protein intake to around 10% to 15% of a day's calories, which means that a single cup of black beans could put you in range of a daily limit. Besides, that cup of black beans will also serve up a hefty dose of carbs.
- Most fruits. A single apple could put you over your carb count for the entire day. Check the nutrition facts before you indulge in fresh fruit.
- Milk. Again, too high carb. A cup of whole milk has 12 grams, while the same amount of whipping cream has less than eight.
While it might seem tough to limit carbohydrate intake this strictly, there's one important loophole to keep in mind. Because some carbs come from dietary fiber, which the body doesn't break down and absorb, keto dieters can subtract those from their daily count.
This number is called net carbs, and it's a better measure of how many carbohydrates you're ingesting. For example, while a medium carrot has six grams of carbs, about 1.7 of them are dietary fiber, making chewing up a carrot a net carb intake of just over 4g. Likewise, more than 75% of the carbs in spinach are fiber, making it a relatively safe choice for keto-ers. Kirkpatrick suggests dieters limit their net carb intake to 25 grams a day.
Like any restrictive diet, it's hard to get a balanced plate of all the vitamins and minerals your body needs to stay healthy on a keto plan, so you might also have to supplement with things like extra calcium, potassium, and magnesium. The keto diet is not doctor recommended for pregnant women, people with liver and kidney problems, or anyone prone to gout.
Whatever your goals, it's essential to talk with a professional dietitian or doctor before embarking on the diet.