The Duchess of Cornwall has warned "ridiculous" fad diets are putting people at risk of osteoporosis.
Camilla suggested trends like clean eating, which can see people cut out calcium-rich foods, are "the worst thing to do".
The duchess, whose mother Rosalind died from the fragile bone disease in 1994, is president of the Royal Osteoporosis Society and has supported the organisation for two decades.
She called for more to be done to get the message across to young people that they are taking risks with their health in later life by making drastic diet changes.
"It is this ridiculous dieting, cutting out dairy and all the things that are good for your bones. These girls see ‘Skinny Lizzies’ in a magazine and they all want to be thin. It’s about social media, too," she told the Daily Mail.
“We need to find a way of educating children that they need to take care of their bodies now instead of aspiring to look like someone they see in a picture if they want to protect themselves in old age.”
The duchess’ intervention comes after health officials warned about the negative impact that celebrities, influencers and advertisers are having on children and young people’s mental health by pushing unrealistic body types online, particularly through social media.
The NHS’ National Medical Director, Professor Stephen Powis, said those who peddle get-thin-quick solutions are "taking the health of our young people in their hands and should act with far greater responsibility".
Camilla highlighted the dangers to young people’s physical health, saying: "It’s the fad diets, they are the worst thing to do. You are depriving your bones of calcium. They always say you are what you eat."