Children may be getting far more sugar than they need even though they are drinking fruit juices marketed as healthy and avoid fizzy drinks, a campaign group has warned.
Action On Sugar (AOS) found more than a quarter of the juices, smoothies and fruit drinks they looked at had the same amount of sugar or more than Coca-Cola, which has 10.6g for every 100ml.
AOS examined 200 drinks and the worst contender was Tesco's Goodness Slurper Apple & Banana Fruit Smoothie Snack for Kids, as it contained 16.1g of sugar for 100ml.
Asda's Chosen by Kids Tropical Juice From Concentrate was also packed with sugar - researchers at Queen Mary University in London found 13g of sugar per 100ml in the drink.
Action on Sugar nutritionist Kawther Hashem said it was a concerning finding, given rates of childhood obesity and tooth decay.
She said the survey looked specifically at juices that were aimed at children or marketed as lunchbox-friendly.
Fresh fruit juices - which cannot contain additives like extra sugar - tended to do better than fruit drinks or juices made from concentrate, she said.
But she warned parents against seeing the word "juice" on a label as a green light.
"It wasn't clear-cut, but I do think the ones at the top of the sugar list are usually from concentrate," she said.
She said parents were better off giving their children diluted juice or - better still - water and a piece of fruit.
Concerned parents should also steer clear of artificially sweetened drinks as they were "training" their children's tastebuds for high levels of sugar.
AOS also called for the government to remove fruit juice from their list of suggested ways to get five a day.
Public Health England's chief nutritionist Alison Tedstone said families needed to be conscious of their sugar intake.
But she did not back calls to rethink the inclusion of juice in the five-a-day guidelines.
Fruit juice is a useful contribution towards our five a day, however, because the process of juicing releases sugars from the fruit we recommend that you try to limit your fruit juice to 150mls a day, including that from smoothies and only consume these and other sugary drinks with meals to reduce the risk of tooth decay. >
But the British Soft Drinks Association (BSDA) said fruit juice consumption in the UK equated to an average of just 45ml per person per day - accounting for 1% of the calories in the average British diet.
A spokesman for BSDA also accused AOS of "ignoring the evidence" because they were politically motivated.