A study of almost 17,500 volunteers in the British Cohort Study (BCS) found that 10-year-olds who ate confectionary daily were significantly more likely to have been convicted for violence at the age of 34 years.

The study is the first to examine the long-term effects of childhood diet on adult violence.

Cardiff University researchers found that 69 percent of the participants who were violent at the age of 34 had eaten sweets and chocolate nearly every day during childhood, compared to 42 percent who were non-violent.

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,” Moore said, according to a Cardiff statement.