The concern is mainly free or added sugars: those added to foods and drinks plus the sugars in honey, syrups and fruit juice. A widely used target is to keep free sugars under about 10 percent of total calories, with under 5 percent being even better. For many adults that means roughly 25 to 30 grams (about 6 to 7 teaspoons) a day, and less for children.
Naturally occurring sugars within whole fruit, vegetables and plain milk are not counted the same way, because they come packaged with fibre, water and nutrients. The biggest single source of free sugar for many people is sugary drinks.
Excess free sugar contributes to weight gain, tooth decay and a higher risk of type 2 diabetes. Reading labels, choosing water over sugary drinks, and cutting back gradually all help. People with diabetes or weight goals should ask a doctor or dietitian for a target suited to them.