STARBUCKS' summer pink drink contains nearly 14 teaspoons of sugar — twice an adult's daily allowance.
Its Ruby Flamingo Frappuccino has chocolate chips, raspberry syrup and whipped cream.
A large Venti cup contains 53.8 grams of added sugar and has 474 calories — almost the same as two McDonald's hamburgers.
The medium-sized Grande contains 41.2g. The smallest size on the menu has 29.7, the recommended daily maximum.
The drink is promoted with brightly coloured animated gifs.
Nutritionist Katharine Jenner, from Action on Sugar, called for such drinks to cut sugar levels.
She said: "Unless these are reduced these drinks will contribute to the high levels of obesity, type 2 diabetes and tooth decay, all of which are preventable and cost the NHS billions of pounds each year."
Dr Saul Konviser of the Dental Wellness Trust added: "Consumers need to be aware of the excessive amounts of sugar in these drinks.
“Coffee shops must be more responsible and stop putting profits before the health of our nation."
Starbucks said customers can make a special request for a "Mini" size cup with 197 calories and five teaspoons of sugar — but can also ask for skimmed milk and no cream.