Current WHO guidelines say sugars should make up less than 10% of total energy intake per day for adults and children. For adults of a normal weight, this is the equivalent of around 50g - 12 level teaspoons - of sugar.
In new draft guidelines, the WHO maintains its original advice that sugars should be less than 10% of total energy intake per day.
But it argues that cutting this intake to less than 5% would bring "additional health benefits" and is the "ideal" figure that people should aim for.
The guidelines follow several studies on the impact of sugar on obesity and dental cavities, including the role of "hidden" sugars.
The WHO's limits on intake of sugars apply to all monosaccharides (such as glucose, fructose) and disaccharides (such as sucrose or table sugar).
These are added to food by the manufacturer, the cook or the consumer, and are also naturally present in honey, syrups, fruit juices and fruit concentrates.
The WHO said much of the sugars consumed today are "hidden" in processed foods such as sweets.
Dr Francesco Branca, director for nutrition for health and development at the WHO, told a news conference that the 10% target was a "strong recommendation" while the 5% target was "conditional", based on the evidence.
Dr Branca said obesity affects half a billion people around the world and is on the rise among all age groups.