According to Action on Sugar, sugar content is “dangerously” high in some flavoured coffees and other hot drinks.
Analysis on 131 hot flavoured drinks by the charity found that 98% of the drinks tested would receive a red nutritional value label for high sugar content, while a third of the hot drinks tested contain at least as much as the nine teaspoons of sugar found in a can of Coca Cola.
Research has also found that teenagers and young adults were most likely to want coffee flavoured with syrups because it makes the brew more palatable.
Action on Sugar’s Kawther Hashem said chains should do more to drastically reduce the amount of sugar in the drinks by reformulating flavoured syrups and only sell the drinks in small sizes.
She said: “I think teenagers and students really like caramelised syrup coffee, the reason is generally coffee is quite bitter and young people are not accustomed to that.
“If they get a caffeine hit and a sweet hit, these drinks will appeal to them. That is storing up trouble for future generations.”
The drink found to have the highest sugar content was Starbucks’ venti Grape with Chai, Orange and Cinnamon Hot Mulled Fruit, with a total of 25 teaspoons of sugar per serving.
Costa’s massimo eat-in Chai Latte was found to contain 20 teaspoons of sugar while Starbucks’ venti White Chocolate Mocha with Whipped Cream was found to have 18, a a campaign group spokesman added.
A Starbucks spokeswoman said: “Earlier this year we committed to reduce added sugar in our indulgent drinks by 25% by the end of 2020.
“We also offer a wide variety of lighter options, sugar-free syrups and sugar-free natural sweetener and we display all nutritional information in-store and online.”
Kerry Parkin, head of communications at Costa, added: “Costa takes the nutritional balance of our food and drink very seriously and we have already taken significant steps to reduce the sugar content of our ranges.
“We intend to continue improving the balance of our product offerings while maintaining the high quality and great taste our customers expect. This April we will be setting salt and sugar reduction targets for 2020.”