The World Health Organisation is advising people to halve the amount of sugar in their diet in order to combat obesity and tooth decay.
The UN health agency said it was maintaining its 2002 guidelines that sugars should make up less than 10 per cent of total daily energy intake, however it stressed that 5 per cent would be preferable.
That means adults with a normal Body Mass Index should eat less than six teaspoons of sugar each day to avoid health risks.
That includes all sugar added to food and beverages as well as natural sugar in things like honey, syrups and fruit juice, the WHO said.
The WHO's director of nutrition for health and development Francesco Branca says the recommendation is part of the global fight against obesity.
"It is definitely worsening. We calculate there's a half a billion people that are affected by obesity and that is on the rise," she said.
"We see more and more kids, even from early ages such as before five years, getting more and more overweight and obese, even in low- and middle-income countries."
At least 2.8 million adults die each year as a result of being overweight or obese, not counting the large percentage of diabetes, heart disease and cancer cases attributable to being overweight, the WHO calculates.
Meanwhile, more than 40 million children under the age of five are overweight, it said.
Tooth decay is also a major and very expensive health problem, the agency said, stressing that treatment of dental disease costs up to 10 per cent of healthcare budgets in industrialised countries.
"Much of the sugars consumed today are 'hidden' in processed foods that are not usually seen as sweets," the WHO warned, pointing out that a single can of sugar-sweetened soda contains about 40 grams - or 10 teaspoons - of sugar.