Increased exposure to images of celebrities’ bodies is behind the large rise in the number of young girls being admitted to hospital with an eating disorder, a leading paediatrician has claimed.

Dr Colin Michie, the chairman of the nutrition committee at the Royal College of Paediatrics and Child Health, blamed the increase on children’s use of mobile phones and exposure to advertising, citing their ability to constantly look at images of celebrity bodies as a factor in eating disorder cases.

He said: “Adverts for children are a very powerful force. I think we have released a behemoth we cannot control.

“It’s not just peer pressure. Children do have a problem with food that is different to problems they had before.”

Soaring numbers of children and young people are being taken to hospital for sometimes months at a time because of eating disorders, NHS figures show.

While 658 under-19s in England needed a spell in hospital in 2003-04 to treat an eating disorder, by 2013-14 that number had increased to 1,791, up 172%. More than 90% of them were girls and young women, with teenage girls among the likeliest to become an inpatient, usually because they were suffering from anorexia nervosa.

The figures also show that the number of 14-year-old girls ending up in hospital because of an eating disorder jumped from 74 in 2003-04 to 336 a decade later, with a similarly steep rise – from 87 to 336 – among 15-year-olds.

Just 135 of those under 19 who were admitted last year because of eating disorders were boys, or 7.5% of the 1,791 people admitted. The biggest leap in that age group was from six to 50 among 13-year-olds.

Specialists said other reasons for the increases could be down to people’s health worsening as they faced long delays to access care, better recognition by doctors of the risk of death facing anorexia patients or improved diagnosis of conditions which have the highest death rate of any mental illness.

Beat, the eating disorders charity, said the rise was startling but the figure may reflect better detection rather than an actual increase in cases of very serious eating disorders. Rebecca Field, its head of communications, said: “Worryingly, it could be attributed to treatment not being available early on in individuals’ illnesses as an outpatient, eventually necessitating hospitalisation.”

Ulrike Schmidt, professor of eating disorders at King’s College Hospital, said: “Clinicians might be becoming more risk adverse and admit more quickly than 10 years ago, because there is generally more awareness of the risks of anorexia nervosa. It could be to do with patients having to wait a long time for specialist treatment or services in the community and deteriorating while waiting so that they need to come into hospital.”

Prof Janet Treasure, the director of the eating disorders unit at South London and Maudsley NHS mental health trust, said: “It is sad to see this increase in admissions in the face of evidence that having families involved in treatment decreases the need for inpatient care and reduces the readmission rate after inpatient admission.“Sometimes patients with severe eating disorders can end up staying in hospital for a year or longer, even up to two years, though those cases are rare. The average is about five months.”

Other new research from the NHS Choices website showed that “underweight teen girls” is the second most common subject teenage girls search for information about when they visit it, while “treatment for eating disorders” is the third most popular. For boys, “underweight teen boys” is the third most common subject looked for.

Field said: “It is encouraging to see that girls are so frequently searching for information about eating disorders and treatment on the NHS Choices website, and the fact that ‘underweight boys’ is the third most prevalent search term for boys accessing the site reflects continuing research suggesting males may account for a quarter of all cases of eating disorders.”

The sharp rise in patients with eating disorders needing a spell in hospital came as the Health and Social Care Information Centre (HSCIC) disclosed that the numbers of teenagers and young people – but not under-10s – needing hospital stays as a result of mental and behavioural illnesses has also risen.

The figure went up 13% from 8,112 to 9,194 among 15-19 year olds of both sexes between 2008-09 and 2013-14, and by 12% among 20-24 year olds. However, HSCIC could not explain how the same period saw falls of 25% among 10-14 year olds and 21% among those aged five to nine.