A new study claims that a strictly healthy diet for your children is not as good for their emotional well-being as being allowed of some junk.

The Department of Health funded a study to look at different factors that may affect the happiness or worry of children. Almost 13,000 children were part of the NatCen Social Research study which found that seven-year-olds who are allowed to have some snacks, sweets and television time are happier than those who take either too much or none at all.

Researchers analyzed the effect of healthy eating and television in children and arrived at an inconsistent conclusion. The report shows that children who enjoy PE at school are generally happy and those with parents who have good health demonstrated higher happiness levels in their everyday lives.

The research also shows that children who ate cakes and biscuits were happier than those who either were not allowed to eat such snacks or ate too many sweets, crisps and fizzy drinks. Likewise, children who were allowed to watch an hour of television scored higher happiness levels than those who spent over five hours of TV a day and those who didn't see any. Curiously, young adolescents who ate fast food at least once in a week were happier than those who had takeaways rarely or never.

"Being happier and lacking worry does not mean never having sweets, snacks and television. In fact, there was some indication in the results that higher well-being was more likely when these were enjoyed in moderation. The influence of a healthy diet and plenty of exercise on well-being was likely to be more complex and longer term," the study said.

Eating greens was also not an indication of happiness, at least not for children. Thirty-five percent of those who said they were always happy had three or more fruits and/or vegetables, 36 percent had one or two servings and 38 percent ate no greens. "Eating fewer than the recommended five-a-day portions of fruit and vegetables was not significantly related to wellbeing," the study's lead author Jenny Chanfreau said. "Not least that behaviors learnt early in life may continue into adulthood and, unlike among children, adults who eat more fruit and vegetables do have higher levels of well-being.

The study also concluded that family, friends and school problems have a negative effect on the well-being of children.