There were almost 1,200 hospital admissions in the last year for children aged 16 and under suffering from eating disorders.
New figures from the Health and Social Care Information Centre (HSCIC) show hospitals in England dealt with 2,560 admissions overall for people with eating disorders in the 12 months to October, up 8% on the 2,370 cases in the previous year.
Young children and teenagers make up the bulk of those needing hospital treatment, with big rises among youngsters aged 10 to 19.
The data shows that between November 2012 and last October, 1,185 cases related to children aged 16 and under.
This included 32 admissions for children aged five to nine, alongside six under-fives.
Among those aged 10 to 14, some 595 admissions were made, a 14% jump on the previous year, while 916 admissions occurred among 15 to 19-year-olds, a 16% rise on the previous year.
There were also significant jumps among older age groups, although the total number of cases was much smaller.
Overall, there were 16 cases among 10-year-olds, with 15 girls admitted and one boy.
There were also 49 admissions among 11-year-olds, with 45 for girls and four for boys, and 70 among 12-year-olds, with 63 for girls and seven for boys.
A further 162 admissions were for girls aged 13, and 53 admissions were for boys aged 13.
Among 14-year-olds, there were 226 admissions for girls and 19 for boys, together with 298 for 15-year-old girls alongside 25 for 15-year-old boys.
For 16-year-olds, there were 214 admissions for girls and 15 for boys.
A spokeswoman for the eating disorders charity Beat said: "Today's figures from the Health and Social Care Information Centre are worrying and the tip of the iceberg as they only show inpatient figures.
"We know that the majority of individuals are treated as outpatients within their community as well as in private treatment centres - or worst still, not treated at all.
"Inpatient treatment should be the last resort. We know the sooner someone gets the help they need, the more likely they are to make a full recovery. These figures highlight that early effective treatment is not in place for all."
Overall, there were nine times as many girls and women as boys and men admitted to hospital for an eating disorder, with the most common age for girls being 15 and 13 for boys.
Three in four of all admissions were for anorexia (76% or 1,940 admissions) and one in 20 were for bulimia (5% or 130 admissions). Other eating disorders accounted for one in five hospital admissions (19% or 500 cases).
One in 17 (6%) patients with an eating disorder stayed in hospital for longer than six months.
Care and support minister Norman Lamb said: "We take the issue of eating disorders very seriously, especially among young people, and it is extremely concerning to see the numbers of admissions rising.
"It is vital young people get the help and support they need quickly, which is why we are investing £54 million into improving access to mental health treatments through the Children and Young People's Improving Access to Psychological Therapies programme.
"We are determined that we get to a point where mental health is treated with as much importance as physical health and our recent mental health action plan will drive improvements to services for all, including those with eating disorders."