The idea comes from a 2018 study involving more than 10,000 people in the US, UK and Australia. Participants submitted stool samples and reported what they typically ate. Researchers analysed the microbes in those samples and found that people who consumed more than 30 different plant foods a week tended to have a more diverse gut microbiome than those who ate fewer than 10.
But that doesn’t mean 30 is a magic number. Whether you eat 25 plants a week or 30 is probably less important than some would have you believe.
