MOST PEOPLE mention the poo hammock. At this stage you would have already eaten (and digested) your blue cookie. The paper cradle is stretched across the toilet bowl, ready to catch. Then you will be ready to take out your scoop, before carefully placing your sample in the tube, all set to pop in the post.
Gut health is having a moment, and no company has seized the zeitgeist more than ZOE. You may have been told about it, by someone manically monitoring their glucose or chomping down chia seeds. Hundreds of thousands of people (ZOE won’t say exactly how many) have signed up to pay £25 ($32) a month for the personal-nutrition app—on top of a £300 joining fee. The startup earned £66m in the year to August 2024, an eleven-fold increase on its first year of trading, in 2022.
ZOE’s focus on gut health—all those posted tubes are for testing the gut microbiome—aligns with a surge in interest in links between diet and health, as opposed to weight. By using AI to derive insights from users’ data and an algorithm to generate personalised advice, it has nestled into a booming modern wellness industry. The company is backed by a swarm of social-media influencers; its podcast (“Is there a healthy way to eat oats?“) has 2.5m monthly listeners, more than the Guardian’s flagship news show. Tim Spector, the ubiquitous epidemiologist who co-founded ZOE, has fronted a Netflix documentary called “Hack Your Health”. Last year he unveiled “The Gut Shot”, a fermented-milk drink sold in M&S, a supermarket.
Yet in other ways ZOE is not so modern. Like others before it with a diet to peddle, the company has employed a small army of scientists to prove its method. In May its largest study yet revealed that—shock—“ZOE works”: users were less hungry, more rested and more energetic. Other scientists remain dubious of the idea that continuous glucose monitoring and personalised diets are any better than general healthy-eating advice. In the British Medical Journal, Margaret McCartney and Deborah Cohen criticised ZOE’s scientists for failing to establish a proper control group, or mitigate placebo effects. “There really isn’t any science behind it, it’s a lot of guff made to look like science,” says Nicola Guess of Oxford University’s Nuffield Department of Primary Care Health Sciences.
The app may be leading the “worried well” to obsess over trivial data. Still, by nudging others to pay more attention to what they eat, it is probably doing more good than harm. The company has yet to turn a profit, in part because of high churn. But it is likely to keep growing fast. Henry Dimbleby, a food thinker, reckons that the surge in interest in gut health and personal nutrition will prove more durable than previous dieting fads. ■
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