If you’re thinking about taking a lunch break while you’re reading this, think again —- Twitter CEO Jack Dorsey only eats one meal a day, and the ex-CEO of Evernote fasts from anywhere from two to eight days in a row.
A long list of Silicon Valley executives are obsessed with this trend, called “intermittent fasting,” claiming it has miraculous effects on one’s brain and body, – but is it really worthwhile, or is it just another fad diet with nothing to show but a growling stomach?
What is intermittent fasting?
Intermittent fasting is exactly what it sounds like: You fast, but only intermittently, and the rest of the time you eat normally. You can combine this eating pattern with other kinds of diets, but for the most part, during your non-fasting periods, you can eat whatever you want. Most often, your fasting period occurs for 16 or 24 hours at a time, twice a week, like Cro-Magnons used to do when their hunting and gathering didn’t yield as much food as needed –— or so the historical myth says.
The most popular modern iteration of this is the 16/8 method, or the “Leangains protocol,” which requires 16 hours of fasting and eight hours of eating. You can also indulge in the Eat Stop Eat method, in which you fast twice a week for 24 hours at a time. If you’re not interested in a complete fast, you can spend those 24 “fasting” hours restricted to 500 calories instead.
As for the effectiveness of intermittent fasting, studies show that, if combined with a healthy diet, it does exactly what you’d want a fast to do: kick-start your weight loss. This can cause anywhere from a 3% to 8% reduction in body weight over the course of up to 24 weeks. But intermittent fasting does more than just help you lose weight; rumor has it that this eccentric eating pattern can have lasting effects on your body and brain.
What does it do to your body?
Intermittent fasting supposedly triggers ketosis, which you’ve likely heard about from the trend of keto diets. In ketosis, your body thinks it’s starving, and as a consequence, it kicks into survival mode by engaging in autophagy —– the breaking down and rebuilding of proteins, primarily in your brain. This can make you feel euphoric, grumpy, sad, dehydrated, and everything in between for the first 12 to 18 hours. By hour 24, though, you’ll probably feel better than you have in a few days.
Primarily, people try out intermittent fasting to lose weight rapidly, but there are other benefits, such as shaping a sharp mind like any of the hungry Fortune 500 CEOs fasting their weekends away will tell you. When in keto, a man’s levels of human growth hormone shoots up —– according to a 1992 study published in The Journal of Clinical Endocrinology and Metabolism. This causes increased muscle tone. Other studies have found that cells heal faster when your body thinks that you’re starving and that this state may lower the body’s susceptibility to oxidative stress, free radicals, and more.
What does it do to your brain?
The effects of intermittent fasting on your body are impressive, but what happens to your brain when you fast is even more striking — but mostly in rodents. Research shows that intermittent fasting has a lasting effect on a protein often referred to as “brain-derived neurotrophic factor,” or abrineurin, also called BDNF, a neural regenerative factor in both rats and mice. (No human trials have been conducted yet.)
Discovered in the early 1990s, this protein facilitates brain growth and helps the brain remain adaptable. There’s a lot that science doesn’t know about abrineurin, but reduced levels of it have been linked to depression, schizophrenia, Alzheimer’s, and the effects of aging. Other studies have found that BDNF has a positive effect on everything from fear conditioning to glucose and cardiovascular regulation — in mice, of course. It’s also become the secret obsession of many Silicon Valley tech companies who are looking for ways to “hack” their brains, and change their neurochemistry for the better.