Drinking lots of fizzy drinks can damage our brains and lead to hyperactivity, according to new research.
Jane Franklin, a researcher at Macquarie University in Sydney, said there had been an 'alarming increase' in the consumption of sugar-sweetened drinks in most Westernised societies and warned they should only be consumed as a treat.
"For many adults (and children), these drinks represent a substantial proportion of their daily calorific intake," she said.
"Our research suggests that the long-term consumption of sugar-sweetened drinks in place of water can cause long-lasting changes to behaviour and a profound change in the chemistry of the brain.
"If you are thirsty, drink water. Soft drinks should be enjoyed in moderation."
She added: "I think we can say that drinking too many soft drinks can affect brain chemistry, as well as your waistline. So think before you drink."
Sugary drinks have long been associated with increased risk of heart attacks, diabetes, weight gain, brittle bones, pancreatic and prostate cancer, muscle weakness and paralysis.
But the latest study focused on their effects on the brain rather than the rest of the body and found that they could 'profoundly' change our brains.
Drinking a sweet drink over a long period can lead to hyperactivity and alter hundreds of proteins in the brain, scientists found.
The research, by Australian scientists, was carried out on rats that were fed sugary water.