Half of girls and a third of boys are willing to take drastic measures to reach their ideal body shape or weight, a study has found.
The survey of 810 girls and boys aged 11 to 16 found that one in ten boys would take steroids for a more muscular physique, while one in eight girls would be happy to pop diet pills or laxatives to help them to lose weight.
Over 50% of girls and more than a third of boys said they compared their bodies with those of celebrities on TV.
About a quarter of both girls and boys even said they would be willing to undergo cosmetic surgery to achieve their ideal look.
Rosi Prescott, chief executive of Central YMCA, the charity that commissioned the survey, said:
"Young people appear to be increasingly insecure about their appearance and body image.
"There is a growing trend to resort to quick fixes, which are damaging to health and often unfulfilling.
"It is also interesting that what used to be seen as a problem affecting young girls has now spread to young men.
"The root cause of this problem is the pressure on young people to conform to an unattainable and unrealistic body image ideal."
Today, an all-party group of MPs will begin a landmark inquiry into body image in the UK, including the problems of anorexia, obesity and self-harm.
Lib Dem MP, Jo Swinson, will chair the inquiry.
She told The Independent On Sunday: "In the past 15 years, eating disorders have more than doubled.
"There is a view that we should tell people they should be really thin because we are getting an obesity problem. But starving ourselves is not a healthy way to lose weight."
The inquiry follows a recent study by the Centre for Appearance Research, which found that one-third of teenagers will not join in a classroom debate to avoid drawing attention to the way they look, while a fifth said they would stay away from school on days when they are concerned with their appearance.