Childhood creativity is being stifled by a combination of junk food, school targets and mass marketing, a group of authors and academics has claimed.
Children need "real" food, the experts say
Dozens of teachers joined children's authors and psychologists to write a letter to the Daily Telegraph.
The signatories highlighted "the escalating incidence of childhood depression" and demanded action.
Children's writers Philip Pullman and Jacqueline Wilson, and scientist Baroness Greenfield signed the letter.
In their letter - entitled: Have we forgotten how to bring up our children? - lead signatory Sue Palmer, author of Toxic Childhood and a former head teacher, claims the government has failed to understand how children develop.
The group also includes former Children's Laureate Michael Morpurgo, child care expert, Dr Penelope Leach and environmentalist Sir Jonathan Porritt.
They warn that poor diet, restricting exercise, putting children in "academic straitjackets", and dressing them like "mini adults" will "restrict their creativity and enrichment".
The end of their letter reads: "Our society rightly takes great pains to protect children from physical harm, but seems to have lost sight of their emotional and social needs.
"However, it's now clear that the mental health of an unacceptable number of children is being unnecessarily compromised, and that this is almost certainly a key factor in the rise of substance abuse, violence and self-harm amongst our young people."
The group has also recommended a public debate be initiated on "child-rearing in the 21st Century", which should be "central to public policy-making" in the future.
Bob Reitemeier, chief executive for The Children's Society, said that there was "fear and confusion surrounding childhood".
"The childhood experienced by today's children is significantly different from that of previous generations," he said.
"Despite our wealth as a nation, the well-being of children in the UK is amongst the lowest in Europe.
"Too many children in the UK are still experiencing poor childhoods."
He said the charity was opening an independent inquiry into childhood which would inform future debate.
Patrick Holford, a psychologist and nutritionist, who heads the Food for the Brain Foundation, believes swift action is needed to help children.
He said: "There is absolutely no question that there is a profound link between children, their poor performance and a poor diet."