Researchers from the University of Toronto analysed more than 40 studies, looking at the body mass index (BMI) of both children and adults who drank fruit juice for at least two weeks.

They found that children who drank at least eight ounces of fruit juice a day saw an average increase in their BMI of 0.03.

“Our systematic review and meta-analysis of prospective cohort studies in children demonstrated a positive association between 100% fruit juice consumption and change in BMI, with younger children showing higher BMI for each additional serving per day than older children,” the researchers said.”

They found that, on average, an 11-ounce bottle of orange fruit contains just about eight-and-a-half teaspoons of sugar, while a 12-ounce can of Coke has nine-and-a-half teaspoons. ​​ “Our findings support guidance to limit consumption of fruit juice to prevent intake of excess calories and weight gain,” they said.

While this study may say Diet Coke is preferable to fruit juices, Better Health Victoria advises that all sugar-sweetened drinks are “not recommended or needed” for children.

“Intake of sweet drinks reduces the quality of your child’s diet, has links to weight gain and poor oral health, and also exposes them to the ‘habit’ of drinking sweet drinks,” it says.