A poll that asks children if they think they’re “much too fat” in relation to their body image has been called "shocking" and "appalling".
The survey was sent to 210 Welsh schools with pupils aged 11 to 16, BBC Wales reported.
The Welsh Government, Public Health Wales and Cardiff University commissioned the study from Ipsos Mori to better understand health problems young people face.
But the poll has been slammed for the multi-choice body image question which includes three answers - "much too fat", "much too thin" and "about the right size".
Bethan Sayed, ex- chairwoman of the Senedd eating disorders group, said the question had "shocked and appalled" her.
She told BBC Wales: "Somebody who may never have thought they would have an eating disorder may develop one from answering such an absurd question."
Holly Rhys-Ellis, 26, who had an eating disorder added: "Why don't we concentrate more on people's qualities, their interests, how they feel, do they exercise?
“Maybe concentrating more on those things rather than how people look.
“If people then feel they are fat or thin, or however they feel, then they can discuss it if they bring it up, rather than putting those words in people's faces.”
The body image question is included in the World Health Organisation's health behaviour in school-aged children survey and has been a mandatory part since 1993.
The poll has also been used in England, Scotland, and more than 50 countries in Europe.
Questions about foods, activity, substances and bullying are also included.
Sally Holland, children's commissioner for Wales, said she was in touch with the research team and understood the question had caused alarm.
She said: "In light of the concerns raised with us we are in touch with the research team about this question and its context, including its development, testing, and the support and guidance offered to schools and pupils."
A spokesman for Cardiff University spokesman added: "The question is one of a range included in the survey capturing predictors of health and wellbeing outcomes and contributes to our understanding and national, local and regional responses to the health and wellbeing issues faced by young people in Wales.
"Parents are sent letters with details of the survey, how they can obtain further information or discuss any concerns with the study team and instructions on how they can withdraw their child from the survey."