And a quarter say that the way they look is one of their biggest concerns at the start of the school year.
The youth charity YMCA and toiletry brand Dove surveyed more than 1,000 pupils between the ages of 11 and 16. They found that 69 per cent return to school worried about their body shape, their weight and their skin.
These fears also increase as pupils go through school. While 20 per cent of 11- and 12-year-olds worry about their appearance, this proportion rises with age. By the time pupils are taking their GCSEs, at the age of 15 or 16, one in three – 32 per cent – say that their looks are one of their main concerns about the return to school in September.
Denise Hatton, chief executive of YMCA England and Wales, said that fears about looks can prevent pupils from taking part in PE lessons, or even from raising their hands in class.
“Young people are constantly bombarded with images of unrealistic body types in the media, advertising and online, which can have devastating effects on their confidence and overall wellbeing,” she said.
“Schools are uniquely placed to support young people – to hold positive discussions around body image, and help reduce the negative impact low body confidence can have.”
YMCA and Dove have set up the Be Real campaign, which is calling on teachers to help tackle the negative effects of body image anxiety among teenagers. It is also encouraging heads to adopt a whole-school approach to improving body confidence.