Why are Silicon Valley execs ‘biohacking’ their diets — and is it dangerous?

Gone are the days when three square meals a day and regular exercise were considered enough to stay healthy. Now, Silicon Valley’s elite are trialling new ways to stay mentally and physically on top of their game.

Biohacking, also known as DIY biology, is a broad term that covers a wide range of activities, from going on highly-restrictive diets to micromanaging your sleep patterns. By making these changes, proponents of biohacking hope to improve their minds and “optimise” their bodies so they can function at a higher level.

The phenomenon has garnered a number of high-profile fans, including multiple billionaire tech bosses. Last year, Twitter (TWTR) CEO Jack Dorsey shared his unusual lifestyle routine on the Ben Greenfield Fitness: Diet, Fat Loss and Performance podcast. He starts the day with two hours of meditation and an ice bath and instead of eating breakfast, lunch, and dinner, has a single meal on weekdays. Dorsey added he had done “extended fasts” too, drinking only water on some weekends.

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“I’ll go from Friday ’til Sunday. I won’t have dinner on Friday. I won’t have dinner or any meal on Saturday,” he said. “And the first time I’ll eat will be Sunday evening. I’ve done that three times now where I do [an] extended fast where I’m just drinking water…The first time I did it, like day three, I felt like I was hallucinating. It was a weird state to be in.”

Other tech execs have spoken out about similarly unconventional diets and lifestyles. Mark Zuckerberg once went on a diet that involved only eating animals he had killed himself. The late Steve Jobs famously experimented with a “fruitarian” diet — occasionally eating only apples and carrots for weeks at a time.

While these diets seem extreme, they still pale in comparison to other forms of biohacking. For some, it means getting computer chips implanted or injecting blood from younger people in an attempt to delay ageing. Compared to some of these practices, unusual diets and fasting seem relatively harmless. But are they really?

“Biohacking through diet means that people try and manipulate their diet to improve their health,” explains Chloe Hall, dietitian and spokesperson for the British Dietetic Association.

“Improving your diet in a healthy balanced way can have a range of benefits including weight loss or maintenance, reduced risk of chronic diseases and improved mental wellbeing.”

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There is some evidence that intermittent fasting can be good for you. Evidence is also mounting that intermittent fasting can modify risk factors associated with obesity and diabetes. In a study published in Cell Metabolism, research found that increasing time between meals made male mice healthier overall and boosted their lifespan, compared to those who ate more frequently.

In a review article published in the New England Journal of Medicine, Johns Hopkins Medicine neuroscientist Mark Mattson, concludes that intermittent fasting can be beneficial. Intermittent fasting diets, he says, fall generally into two categories: daily time-restricted feeding, which narrows eating times to 6-8 hours per day, and so-called 5:2 intermittent fasting, in which people limit themselves to one moderate-sized meal two days each week.

“Evidence is accumulating that eating in a 6-hour period and fasting for 18 hours can trigger a metabolic switch from glucose-based to ketone-based energy, with increased stress resistance, increased longevity, and a decreased incidence of diseases, including cancer and obesity,” he wrote.

While there is some evidence of the efficacy of fasting, however, studies also suggest there are downsides. “Using restrictive diets can have dangerous consequences including nutrient deficiencies, reduced social interactions and have an impact on mental health,” Hall said.

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It is difficult to make generalisations about whether fasting is beneficial when there are so many different forms of the practice. Much of the research that supports intermittent fasting applies to moderate fasting cycles, for example, the 5:2 diet. This is very different from drinking only water for a week — or existing only on certain types of fruit.

It’s also tricky to tell if a restrictive diet borders on a problem such as an eating disorder. Even if fasting diets work well for some people, researchers suggest depriving yourself of food could lead to disordered eating — particularly if such diets are glamorised by Silicon Valley execs.

And while some supporters of biohacking diets report feeling a sense of euphoria, power or mental clarity, research has shown this to be a transient side effect linked to the early stages of starvation. In the 1960s, Scottish doctors observed patients who fasted for up to 249 days. After a few days without food, their appetites subsided and all patients reported an increased sense of wellbeing, including feelings of euphoria.

Researchers have suggested this may be due to ketosis — a metabolic process that occurs when the body begins to use fat for energy because it does not have enough carbohydrates to burn.

It seems unlikely that a highly restrictive diet will give us superhuman abilities, even if there are some benefits to intermittent fasting for some people. If you are considering changing your diet, it’s important to consult your doctor first as skipping meals and restricting eating can be dangerous.

In the US, the National Eating Disorders Association helpline number is 1-800-931-2237. In the UK, B-eat can be contacted on 0808-801-0677.