The mysterious case of declining nutrition in food

I LOVE playing detective. So when I found myself on a train scrolling through hundreds of shocked responses to yet another viral tweet claiming that the proportion of nutrients in our fruit and veg has collapsed over recent decades, I thought I better do some digging.

This ubiquitous, yet generally poorly evidenced, claim is one that I have explored in a previous column. However, as the new tweet cited a 2018 study that is more recent than many I have looked into before, it seems important to return to the issue, particularly given its new-found influence on social media.…