This piece is going to be reissued as an archive podcast for Guardian Long Read in May 2023. It’s one of the articles that meant the most to me, because the evidence is now clear that ultra-processed food – a term coined in Brazil over a decade ago – is the key driver of diet-related ill heath around the world, something I also write about in my book THE WAY WE EAT NOW. Yet the majority of people couldn’t say what ultra-processed food even is. The danger is partly that the term can sound very science‑y and technical when really what we are talking about is simply most of what is now sold as ‘food’. So I felt I responsibility to get this piece right and to explain UPFs in a way that was engaging and readable. It went through many drafts before I was even half happy with it.