Lock up those cookies, keep those chocolate bars away. Letting your children eat sweets could turn them into aggressive adults, according to psychiatrists. The surprising claim is made by researchers who found that children who ate sweets and chocolate every day were more likely to be violent as adults.

It is a result of an analysis of almost 17,500 participants in the 1970 British Cohort Study, which showed that 10-year-olds who ate confectionery daily were significantly more likely to have been convicted for a violent crime in their early 30s.

Psychiatrists from Cardiff University found that 69 per cent of the participants who were convicted as adults had eaten sweets nearly every day during their childhood, compared to 42 per cent who were not violent.

The researchers say they controlled for other factors, such as social deprivation, and the link between eating sweets and later violence remained. Simon Moore, who led the study said: "Our favoured explanation is that giving children sweets and chocolate regularly may stop them learning how to wait to obtain something they want.

Not being able to defer gratification may push them towards more impulsive behaviour, which is strongly associated with delinquency." They also added that eating sweets "may nurture a taste for sweetened food", which in later life will lead to exposure to additives, "the consumption of which may also contribute towards adult aggression".