One of the most concerning trends in cancer is that rates of the disease in people under 50 are on the rise. And we don’t know why.

Now, a group of respected British researchers say that part of the explanation is that people are getting fatter. But other experts are sceptical.

What do and don’t we know about this disturbing phenomenon – and what can people do to reduce their risk?

Shorts

Cancer is a disease that usually affects older people, with nine in 10 tumours arising in people over 50.