Extreme diet or disordered eating? That’s the question that began circulating on Twitter CEO Jack Dorsey’s own social-media platform after the executive revealed his unconventional eating habits, which add up to just five meals every week.
During an appearance on the fitness author Ben Greenfield’s podcast, Dorsey said he’s been “experimenting” with a new fasting routine that involves eating a single meal on weeknights, followed by a weekend-long fast.
“It really has increased my appreciation for food and taste because I’m deprived of it for so long during the day,” Dorsey told Greenfield.
Read more: Twitter CEO Jack Dorsey says he’s been ‘playing with fasting’ and only eats one meal per day. Here are the diets of other notable tech billionaires.
On days when Dorsey eats, he fasts until 6:30 p.m., at which point he’ll consume a protein (either fish, chicken, or steak) and some vegetables (an arugula or spinach salad, asparagus, or Brussels sprouts). Then he’ll have a dessert of mixed berries or dark chocolate, which he consumes before 9 p.m.
There’s also some bone broth thrown in when he breaks his fast on Sunday night, and some red wine, though the CEO didn’t specify how often he consumes alcohol.
While fasting diets are increasing in popularity, nutrition experts say extreme routines such as what Dorsey describes could have long-term health consequences.
Intermittent fasting has become a trend in Silicon Valley
Dorsey has described his diet as “prolonged fasting,” though nutrition experts say it falls within the realm of intermittent fasting, a plan that oscillates between defined periods of eating and not eating.
Variations of the diet have become increasingly common among Silicon Valley tech workers seeking efficiency in their eating routines. Dan Zigmond, Facebook’s director of analytics, fasts for 15 hours a day, and former Evernote CEO Phil Libin founded an entire community dedicated to intermittent fasting called WeFast.
These fasting diets are part of a longstanding Silicon Valley “biohacking” trend, in which people meticulously tweak their diets and daily habits to live longer and be more productive.
Like some of his fellow tech executives, Dorsey has said his diet helps him save time, stay focused, and sleep better at night — but science has yet to definitively prove the health benefits of a fasting diet for most people, including intermittent fasting. In fact, some nutrition experts said Twitter users who called Dorsey’s reported diet “disordered eating” are right.
“Yes, that is disordered,” said Dr. Jennifer Gaudiani, CEDS, FAED, an internal-medicine doctor who specializes in eating disorders. “Humans are mammals that need certain amounts of food and fluid to maintain our physiological species and energy to do things we want to do in the world.”
Limiting yourself to one meal per day could result in malnourishment
Dorsey’s dinner of lean protein and vegetables resembles a kind of diet given to obese patients trying to lose 50 pounds or more, according to Dr. Caroline Apovian, who directs the nutrition and weight-management program at Boston Medical Center. Even then, patients are recommended to consume three meals a day.
That might explain why Dorsey had some trouble transitioning to his fasting routine. “The first time I did it, like day three, I felt like I was hallucinating,” Dorsey told Greenfield. “It was a weird state to be in.”
Read more: The amazing ways intermittent fasting affects your body and brain
Apovian said the CEO’s body probably wasn’t prepared for a change in its circadian rhythm. “Dorsey’s body initially was saying, ‘Hey, what are you doing? Where’s my meal?'” she told Business Insider.
Although Apovian said our bodies can learn to adjust to new eating practices, she believes an active person such as Dorsey — who either walks five miles to work, does a seven-minute workout, or hops on a stationary bike each day — could become malnourished by eating so little.
To balance out a diet such as Dorsey’s, Apovian recommends a breakfast of whole grains, steel-cut oats, fresh fruit, and low-fat dairy a few hours after waking up or an hour before exercise.
The best way to care for our bodies, Gaudiani said, is to “nourish ourselves throughout the day.”
Fasting might seem like it improves mental acuity, but it can backfire
Dorsey told Greenfield that since starting his new diet, his ability to concentrate and fall asleep quickly have improved significantly. But Gaudiani said those kinds of results can indicate that someone’s body is going into survival mode because of starvation.
When a person severely limits their food intake, the body will use evolutionary instincts in order to keep itself alive. “When people undercut their need for food with radical under-eating, the body doesn’t care about the reasoning. It is just going react to save your life,” Gaudiani said.
That reaction will include feelings of mental sharpness because the body is trying to determine when and where from it will get its next meal. “Animals who are starved shouldn’t feel playful,” Gaudiani said. “They should feel concerned and focused. They may interpret that initially as productive, but it’s the brain saying, ‘I don’t have enough food.'”
In some cases, mental sharpness can turn into feelings of panic or paranoia because of survival instincts. In the long term, starvation can lead to decreased testosterone levels (and therefore decreased sex drive), fragile bones, poor skin, hair loss, and early signs of aging.
There’s minimal evidence that intermittent fasting can help with productivity or weight loss
Because dieting is highly personal, what works for some might not work for others. “It may be that somebody does really great eating one meal a day,” Apovian said.
When it comes to intermittent fasting, however, Apovian said there’s little scientific evidence that the practice can help people lose or maintain weight any more than a traditional three-meal plan. In most cases, she said, fasting encourages people to “semi-starve” themselves during the day, which leads to overeating at night.
Though preliminary research has found that intermittent fasting may reduce the risk of diabetes, cancer, and heart disease — and help with weight loss — scientists still need more evidence to determine its effects on human health.
“Our body needs fuel to function,” said Zhiping Yu, an associate nutrition professor who received her Ph.D. from Pennsylvania State University. ”
Without fuel from food for a long time, our body, including [our] brain, will experience problems,” including disrupted hormone levels and slower metabolisms, she added.
Abnormal fasting practices could be a form of disordered eating
According to Gaudiani, eating in an abnormal way — severely restricting calories, denying yourself food when you’re hungry, or limiting the types of foods you eat — qualifies as disordered eating, even if it’s not purposeful. Disordered eating differs from an eating disorder, in that a person with an eating disorder actually fears food and is limiting caloric intake to achieve a specific body ideal.
While some intermittent-fasting practices could qualify as disordered, it’s impossible to diagnose any one CEO’s eating habits, including Dorsey’s, without knowing them personally.
Even so, Gaudiani said any celebrity diet endorsement that isn’t research-backed can “cause harm and perpetuate weight stigma” because it’s not based in science.
“If you have a history of an eating disorder, you should be cautious to try this diet,” Yu said. “If you feel any discomfort when you are doing it, you should consider stopping.”
Better yet, you might want to skip it altogether.