Monitoring dietary intake of sugars in the population’s diet has great importance in evaluating the efficiency of national sugar reduction programmes. The study objective was to provide a comprehensive assessment of dietary sources of added and free sugars to assess adherence to public health recommendations in the UK population and to consider the impact of different sugar definitions on monitoring. The terms “added sugar” and “free sugar” are different sugar definitions which include different sugar components and may result in different sugar intakes depending on the definition. Dietary intake of added sugars, free sugars and seven individual sugar components (sugar from table sugar; other sugars; honey; fruit juice; fruit puree; dried fruit; and stewed fruit) of 2138 males and females (1.5–64 years) from the National Diet and Nutrition Survey (NDNS) 2014–2016, collected using a 4 day estimated food diary, were studied. Added and free sugar intake accounted for 7% to 13% of total energy intake respectively. Major sources of free sugar intake were “cereals and cereal products”, “non-alcoholic beverages”, and “sugars, preserves, confectionery”. Differences between added and free sugar intake were significantly large, and thus use of free sugar versus added sugar definitions need careful consideration for standardised monitoring of sugar intake in relation to public health.

The purpose of the UK National Diet and Nutrition Survey (NDNS) is to provide detailed quantitative data on food consumption, nutrient intakes and the sources of nutrients for the UK population, and an assessment of population nutritional status through objective biomarker analysis. The UK NDNS reports official statistics for ongoing monitoring of diet, to provide the evidence base for developing and evaluating effectiveness of policy and interventions, and for exposure assessment.

The UK National Diet and Nutrition Survey rolling programme (NDNS RP) commenced in 2008 and moved in 2019 from a traditional paper food diary to a web-based 24 h recall, Intake24. This paper describes the approach to update and downsize the underlying UK Nutrient Databank (NDB) for efficient data management and integration into Intake24. Consumption data from the first 10 years (2008/2009 to 2017/2018) of NDNS RP informed decisions on whether foods from the extensive UK NDB were to be retained, excluded, revised or added to for creation of a rationalised NDB. Overall, 5933 food codes in the extensive NDB were reduced to 2481 food codes in the rationalised NDB. Impact on assessment of nutrient intakes was evaluated by re-coding NDNS 2017 data using the rationalised NDB. Small differences were observed between estimated intakes (Cohen’s d ≤ 0.1) for all nutrients and there was a good level of agreement (Cohen’s κ ≥ 0.6) between the extensive and rationalised NDBs. The evaluation provides confidence in dietary intake estimates for ongoing nutritional surveillance in the UK and strengthens the evidence of a good agreement between concise food databases and large food databases incorporated into web-based 24 h recalls for estimating nutrient intakes at the population level.