According to The Evening Standard, Fionnuala Kennedy of Wimbledon High School wrote to parents after she said a Netflix drama she watched, and assumed many students have watched, glamorises mental health issues such as anorexia.
She wrote: "Role model as effectively as you can. It's difficult to advocate a rounded, healthy diet for your teen if you've cut out carbs and dairy yourself, or frequently refer to your desire to lose weight."
Kennedy told the Evening Standard: "We are all a bit culpable - it's quite a middle-class thing talking about cutting out food groups and clean eating."
Christian youth worker and President of the Girls Brigade England and Wales Rachel Gardener told Premier News Hour that she backs Kennedy's stance.
She said: "I think she's an excellent head teacher.
"I think school teachers are often on the front lines and they see first-hand the impact that cultural messages and maybe even parenting styles have on the young people they teach. So I think we need to listen to her. She has something good to say."
Gardner told Premier that it's very easy for parents to inadvertently give children the wrong message. She added that children grow up in a world where adults constantly judge themselves and each other about how they look.
She said that's why it's important that schools, family members and churches take responsibility for healthy and unhealthy messages that young people receive.
She said: "We as Christian youth workers we need to demonstrate that we believe that God cares about our bodies, not just our thoughts and care and emotions and our spirits.
"I think we need to chat with young people about the reality of filters on Instagram and photo editing. They need constant reminding that not everything they see online is true and what that that person actually looks like.
"We say to young people your body changing and fluctuating weight, that's all part and parcel of adolescence. We need to be really vocal about these messages."
Listen to Rachel Gardner speaking with Premier's Alex Williams here:
