“Careless pork costs lives”, wrote The Sun newspaper, a British tabloid, in a headline about the bowel cancer risks associated with eating bacon sandwiches. That scaremongering story was published almost a decade ago, but spurious claims about lifestyle choices and cancer – especially bowel cancer, also known as colorectal cancer – are still rife. The big difference? The alarmist claims are largely playing out on social media and are increasingly targeted at the young.

Why is this? In recent years it has become clear that rates of various cancers are rising in younger people. This is raising questions – and speculation…