Children are facing too many "unhealthy" choices at school dinner time, according to a report.
Work is already being done to provide healthier meals
The charity Barnardo's wants the government to provide more money to ensure better ingredients are served, including fresh fruit and vegetables.
Its survey of 174 children in England, Wales and Scotland found most accepted junk food as the "staple school diet".
The media and peer pressure also influenced the take-up of high-fat, high-carbohydrate choices, it said.
'Chips, chocolate and crisps'
The Department for Education and Skills (DfES) says work is already under way to improve the quality of school meals.
Barnardo's called for schools in England to ban vending machines offering unhealthy snacks and drinks, as is the case in Scotland and Wales.
One 14 year old told its researchers: "I normally have chips, fish, pop, chocolate and crisps. I eat about six bags of crisps per day just because they are there for us."
The findings come amid reports of growing obesity among children.
Neera Sharma, author of the report, Burger Boy and Sporty Girl, said: "If we are really serious about making a difference to the food children eat in schools, we have got to start listening to what they say so that we can understand the meaning food has for them.
"As a society we must reclaim responsibility for what our children eat."
The DfES Healthy Living Blueprint aimed to offer schools "options and ideas" on improving diets, the report said.
But Ms Sharma said: "We don't believe this will go nearly far enough in making a difference to children's views.
"From our research, it appears that children have very fixed attitudes to foods and strong stereotypes of the type of youngsters who eat them."
Boys in particular were associated with a love of burgers.
They could be stigmatised, and even bullied, for eating "uncool" food.
One child was known as "chicken boy" because he ate poultry every day.
The survey involved children in nursery, primary and secondary schools.
A DfES spokesman said: "The government is committed to promoting healthy eating and encouraging schools to provide healthy meals.
"Our recent Healthy Living Blueprint sets out a fully comprehensive range of resources that schools can use to give children the knowledge, skills and understanding they need to lead healthy lives.
"The government is also reviewing the nutritional standards for school meals which were introduced in 2001, the first in 20 years, to encourage pupils to adopt a more balanced diet."