Just one can of fizzy drink a day is linked to more aggressive behaviour by teenagers, claim researchers.
A new study found youngsters were significantly more likely to be violent and carry weapons if they regularly consumed fizzy soft drinks.
The study showed those having more than five cans of non-diet carbonated drinks a week were more likely to get involved in violent assaults.
The US researchers are uncertain if the link is causal, but have not ruled this out.
It is possible that unknown factors causing aggression in youngsters also influence their dietary habits – which is why they opt for fizzy drinks – but previous research suggests poor nutrition may be a cause of antisocial behaviour.
The latest findings, reported online in the journal Injury Prevention (must credit), come from a survey of 1,878 teenagers aged 14 to 18 from 22 state schools in Boston.
They were asked how many cans of non-diet fizzy soft drinks they had consumed over the past week.
Up to four cans was considered ‘low’, and five or more was classified as ‘high’.
Just under one in three pupils fell into the ‘high’ category, some drinking more than two or three cans a day.
The scientists then investigated any potential links to violent behaviour.
Youngsters were asked if they had been violent towards their peers, a brother or sister, or a partner, and whether they had carried a gun or knife in the past year.
Overall, frequent soft drink consumption was associated with a 9 per cent to 15 per cent increased likelihood of engaging in aggressive behaviour.
Violence and weapon-carrying was in any event common among the teenagers, who largely represented ethnic minorities from poor backgrounds. Of the group, 50 per cent were black or multi-racial, 33 per cent Hispanic, 9 per cent white and 8 per cent Asian.
However, rates of violent behaviour increased in a ‘dose response’ as students consumed more fizzy drinks, the researchers found.
Just over 23 per cent of teenagers drinking one or no cans a week had carried a gun or knife, rising to just under 43 per cent of those drinking 14 or more cans.
For the same increase in fizzy drink consumption, the proportion of those who had shown violence to a dating partner rose from 15 per cent to 27 per cent.
Rates of violence towards peers rose from 35 per cent to more than 58 per cent, and towards siblings from 25 per cent to more than 43 per cent.