The daily allowance for a person's sugar intake should be halved to six teaspoons, the World Health Organisation says.
Its draft guidance advises a dramatic drop in sugar consumption to help avoid mounting health problems including obesity and tooth decay.
It proposes to retain its current formal recommendation that no more than 10 per cent of an individual's calories should come from sugar - the equivalent of 12 "level" teaspoons a day for the average adult.
But its draft guidelines say a cut to 5 per cent "would have additional benefits". The lower limit amounts to about six teaspoons.
AdvertisementAdvertise with NZME.
The WHO move comes amid growing evidence that sugar contributes to a range of chronic diseases and follows calls by scientists for the recommendation to be halved.
A study by the University of Southern California disclosed this week found eating too much protein could be as dangerous as smoking for middle-aged people.
Separately, a heart scientist has warned that British National Health Service guidelines advising people to cut down on high-fat foods may be putting the public at risk.
Dr James DiNicolantonio says more focus is needed on the harm caused by high levels of carbohydrates and sugar.
The WHO limits apply to all "free" sugar - sugar added by the manufacturer - plus that naturally present in honey, syrups, and fruit juices.
Its director of nutrition for health and development, Dr Francesco Branca, said a single can of fizzy drink could exceed the amount of sugar children should have in a day.