Where has the idea of eating 30 different plant foods come from?
The suggestion that eating this number of plant foods every week can lead to improved health comes from a large study I worked on back in 2019. The British and American Gut Project looked at the diets of thousands of people, assessing how different dietary patterns were associated with different health outcomes.
One of the most interesting findings was around fibre. The recommended portion of fibre for an adult is 30-35g a day, but what the study was showing us was that the amount of fibre isn’t as important as the variety. Different plants have different fibres, so eating more plants diversifies the types of fibre you eat.
The study showed us that people who ate the largest variety of plant foods were found to have the healthiest microbiomes (the microbe environment that exists naturally in our guts) and were likely to report the best health outcomes. The study suggested that 30 was the optimum number of different plants for fibre diversity, as there wasn’t much improvement when you increased from 30 to 35 or 40.
