People need to more than halve their intake of added sugar to tackle the obesity crisis, according to scientific advice for the government in England.
A draft report by the Scientific Advisory Committee on Nutrition (SACN) says sugar added to food or naturally present in fruit juice and honey should account for 5% of energy intake.
Many fail to meet the old 10% target.
The sugar industry said "demonising one ingredient" would not "solve the obesity epidemic".
The body reviewed 600 scientific studies on the evidence of carbohydrates - including sugar - on health to develop the new recommendations.
One 330ml can of fizzy pop would take a typical adult up to the proposed 5% daily allowance, without factoring in sugar from any other source.
Prof Ian MacDonald, chairman of the SACN working group on carbohydrates, said: "The evidence that we have analysed shows quite clearly that high free sugars intake in adults is associated with increased energy intake and obesity.
"There is also an association between sugar-sweetened beverages and type-2 diabetes.
"In children there is clear demonstration that sugar-sweetened beverages are associated with obesity.
"By reducing it to 5% you would reduce the risk of all of those things, the challenge will be to get there."
The target of 5% of energy intake from free sugars amounts to 25g for women (five to six teaspoons) and 35g (seven to eight teaspoons) for men, based on the average diet.