For adults in the UK, the NHS recommends consuming no more than 30 g of free sugars per day, approximately equivalent to 7 sugar cubes. This is a limit for free sugars, not for all sugars appearing on a food label. Free sugars include sugars added to foods and drinks, plus sugars naturally present in honey, syrups, unsweetened fruit juice and fruit juice concentrates. Sugars naturally contained within whole fruit, vegetables and milk are not included in the UK free-sugar limit. This distinction is essential because a person could consume substantial amounts of naturally occurring sugar from nutritious foods without exceeding the specific free-sugar recommendation.
The WHO recommendation uses a different but complementary framework: free sugars should provide less than 10% of total daily energy intake, with a reduction to 5% or less potentially providing additional health benefits. For someone consuming 2,000 kilocalories per day, 10% corresponds to about 50 g of free sugar and 5% corresponds to about 25 g. Because energy requirements differ among people, a percentage-based recommendation does not produce one universal gram limit. The UK's 30 g adult recommendation provides a simpler population-level limit. Both frameworks support substantially limiting free-sugar intake rather than treating sugar as a necessary dietary component.
The relevant unit is free sugar rather than “total sugar”. A food containing 15 g of total sugars could contain most of that sugar naturally within fruit or milk, whereas another food containing 15 g could consist almost entirely of added or free sugars. The nutrition label alone may not distinguish these categories because UK labels generally display total sugars rather than a separate free-sugars value. Ingredient lists and knowledge of the food's composition therefore help determine whether the sugar contributes to the free-sugar limit. Whole fruit, for example, is not treated like fruit juice even though both contain naturally occurring fructose and glucose.
Sugary drinks are one of the easiest ways to exceed the recommended amount because they can contain large quantities of free sugar in a relatively small volume. The NHS notes that a can of cola can contain around 9 sugar cubes, exceeding the approximate seven-cube daily adult limit by itself. Fruit juice and smoothies also contain free sugars despite their natural origin, which is why UK guidance recommends limiting their combined consumption to 150 ml per day. Water, unsweetened tea and coffee, and lower-sugar or sugar-free drinks can reduce free-sugar intake without reducing hydration.
Excess free-sugar consumption is important primarily because of its effects on energy intake and dental health. Frequent exposure of teeth to free sugars increases the risk of dental caries, while energy-dense foods and drinks containing substantial free sugar can make it easier to consume more calories than required. Free sugar is not uniquely responsible for obesity or metabolic disease, because overall energy balance, dietary pattern, physical activity, genetics and many other factors matter. Nevertheless, reducing sugar-rich drinks and foods is a practical way to improve diet quality, particularly when those products displace nutrient-dense foods.
Children have lower UK free-sugar limits than adults. The NHS recommends no more than 24 g per day for children aged 7 to 10, 19 g for children aged 4 to 6, 14 g for children aged 2 to 3 and 10 g for children aged 1. There is no numerical guideline limit for babies under one year, but added sugar should not be added to their food or drinks and sugary foods and drinks should be minimised. These age-specific figures reflect different nutritional requirements and the importance of limiting free-sugar exposure during childhood, particularly because dental health is vulnerable to frequent sugar consumption.
Reducing sugar does not require eliminating carbohydrate-containing foods. Starchy foods such as potatoes, oats, wholegrain bread, rice and pasta can form an important part of a balanced diet, while fibre-rich fruit and vegetables supply naturally occurring carbohydrates together with vitamins, minerals and fibre. The objective is to distinguish nutrient-containing carbohydrate foods from foods and drinks where a substantial proportion of energy comes from free sugars. WHO recommends that carbohydrate intake come primarily from whole grains, vegetables, fruits and pulses and recommends at least 400 g of fruit and vegetables daily for adults and children over 10.
The practical approach is to treat 30 g of free sugar as an upper daily limit rather than a target to reach. Check nutrition labels, reduce sugary drinks, choose unsweetened versions of cereals and dairy products where practical, and reserve sweets, cakes, biscuits and similar foods for smaller quantities and less frequent consumption. A small amount of added sugar can fit into an otherwise nutritious diet; the relevant issue is cumulative free-sugar intake. People with diabetes or other medical conditions may require individual dietary advice, and the general population recommendations should not be interpreted as personalised treatment targets.
