The scope of the analogy is already endless: we "binge" on Netflix, scroll through social media "feeds", are "served" news in daily "digests"; our inboxes "bulge" while we filter out "spam" ... and when it all gets too much, we take a "digital detox", which is as pointless as doing a juice cleanse then going back to eating junk.
Brewer's broader point is that it's not our phones themselves that are the problem, but what we use them to consume — making screen time a meaningless barometer.
"Our body digests 400 calories from a slice of pepperoni pizza very differently to 400 calories' worth of carrot sticks," she says. "Similarly, an hour of mindlessly scrolling through Instagram affects you differently compared to an hour of language-learning on Duolingo."
Whatever your poison, we're all digital gluttons now. The average thumb scrolls through 90 metres of mobile content every day according to Ari Kesisoglu, Facebook's regional director in the Middle East, Turkey and Africa. And this constant grazing is harming our cognitive fitness.
"It's a useful comparison," agrees Soren Kenner, social media expert and co-author with GP Imran Rashid of Offline, a new book revealing the "mind hacks" Facebook, Instagram, Apple and Google use to hold our attention. "You have junk food and you have junk information — tabloids, clickbait, celebrity gossip. A glut of useless information ... and too much is [bad for you]."
He cites the side effects of excessive social media consumption as "at least as troubling" as those of disordered eating: "Stress, sleep disturbance, anxiety, depression, problems focusing, lowered self-esteem, decision-fatigue."
In much the same way as the obesity crisis has been fuelled by an overabundance of cheap, empty calories, could today's mental health crisis be built on the barrage of information our minds and bodies crave but are ill-equipped to process?
According to Kesisoglu, between the beginning of time and 2003 (when the internet truly began to boom), humankind had generated around 5 billion gigabytes of information.
Now, we create that amount of information every 10 minutes. "But our ability to take in and sift through [it] remains as it was 70,000 years ago, at the outset of the cognitive revolution," says Kenner.
So-called "digital vegans" cut the Big Five tech giants — Amazon, Google, Facebook, Microsoft and Apple — from their lives altogether, setting up custom-built virtual private networks to block them.
Others are trying to get in on the act. Michael Moskowitz, the former chief curator at eBay, launched Moodrise in January. It is described as "the world's first Digital Nutrition app", designed not to get people off their phones, but to consume something different.
Split into six desirable moods (from focused to happy), it streams content that supposedly releases the neurotransmitters that engender them.
There seems a deep irony in turning to yet more tech to deliver us from digital junk.
"It's a little like trying to convince yourself that you can slake your thirst by looking at a picture of a glass of water," says Kenner.
Digital diet
• Have a non-tech lunch hour. Turn off your phone, put it in a drawer and enjoy your lunch without it.
• Schedule set times to look at social media, so it doesn't become your default "brain snack" whenever you're not doing something else.
• Batch your emails and only tackle them at certain times of day. "This is a calm inbox," reads Brewer's email postscript. "You will generally get a reply within 24 hours on business days."
• Try phone-fasting. In his latest book, The Stress Solution, Dr Rangan Chatterjee recommends a 4:1 approach — putting your device in flight mode for one hour of every four that you are awake.
- Telegraph Group Ltd
