The numbers of young people admitted to hospital with eating disorders have doubled in the last three years, according to the NHS. Pro-anorexia and pro-bulimia websites are widely seen as a big part of the problem. We look at what these sites are and why they're seen as so toxic.
A lot of sites and apps specify that users must be aged over 13. Why 13? Vicki Shotbolt explains and offers a guide to the age limits for various popular online activities.