Children who have a poor diet are more likely to become aggressive and anti-social, US researchers believe.
The University of Southern California found a lack of zinc, iron, vitamin B and protein in the first three years caused bad behaviour later on.
At eight years old, children fed poorly were more likely to be irritable and pick fights than those fed healthily.
Aged 11, they swore, cheated and got into fights, and at 17, they stole, bullied others and took drugs.
The researchers analysed the development of more than 1,000 children on Mauritius, an island in the Indian Ocean off the coast of Africa, over 14 years.
They found the more malnurished the children were, the greater the anti-social behaviour later on.
The team took into account factors such as social background, health and education, the American Journal of Psychiatry reported.
Report co-author Adrian Raine said parents could prevent their children developing bad behaviour by ensuring they get better diets.
"Poor nutrition leads to low IQ, which leads to later anti-social behaviour.
"At a societal level, should parents be thinking more about what kids are eating?
"There's more to anti-social behaviour than nutrition, but we argue that it is an important missing link.
"Biology is not destiny, we can change the biological disposition to anti-social and aggressive behaviour."
Fellow researcher Jianghong Liu, of the university's Social Science Research Institute, agreed.
"Identifying the early risk factors for this behaviour in childhood and adolescence is an important first step for developing successful prevention programmes for adult violence."
But Dr Ann Hagell, research development adviser at the Nuffield Foundation, a charitable trust which funds social and education research, raised doubts about the findings.
"I would not dismiss the study out-of-hand but I would be surprised if diet plays a big role.
"In my experience diet is not part of the explanation.
"It can cause hyper activity disorders, but anti-social behaviour is more influenced by parenting and genetics and teen peer pressure in teenage groups."