The present study provides an update on current sugar intake as well as age and time trends of intake of free sugar of children and adolescents in Germany. Even if the median free sugar intake is still above the recommendations, our results show a decline in free sugar intake between 2010 and 2023 among children and adolescents. In a previous publication from the DONALD study, which showed trends in the intake of total, added and free sugar from 1985 to 2016 also among 3–18 year olds [3], free sugar intake decreases since 2005, most notably since 2010. The present analyses indicate that this decreasing trend continued.

A possible reason for the observed decreasing trend in free sugar intake could be an increased awareness of parents and participants themselves on the consequences of high sugar intake or specific sugary foods e.g. sugar sweetened beverages. The high sugar intake of children and adolescents has been a common topic in politics [1] and therefore also in media for many years. Since December 2018, the German government has been pursuing a national reduction and innovation strategy for sugar, fats and salt intake [1]. This includes voluntary reformulation measures to reduce sugar in ready to eat products, so far except sweets as well as a ban on added sugar in children’s teas has also been passed. However, in DONALD we saw a decline in sugar intake already before 2018, pointing towards potential different reasons for the decline. It is furthermore questionable if the DONALD participants habitually consumed already reformulated products or if high-sugar food groups such as sweets, sugar-sweetened beverages and juices were specifically avoided. Previous analyses have shown that the decrease in free sugar intake between 2010 and 2016 is due to a decline in the intake of specific food groups [10]. In particular, the intake of free sugars from sugar-sweetened beverages and fruit juices decreased, while the decline in the intake of free sugars from sweets was less pronounced.

It should be considered critically, that dietary data is self-reported in the present analyses, since the underestimation of habitual energy intake is a common known bias in observational studies [8]. In addition, non-plausible dietary records showed a markedly lower intake level of added sugar than plausible records [8]. Although our sensitivity analysis does not support the notion of bias from general underreporting, we cannot preclude the possibility that the observed decline in free sugar intake partly reflects nutrient specific misreporting. The observed trend in our previous analyses [3] was confirmed using predictive biomarkers for total sugar intake [4]. Replicating the present analyses using biomarker data would help rule out specific underreporting of high-sugary foods.

Regardless of the ongoing decline in free sugar intake since 2010, median intake in this German sample still exceeds the WHO recommendation of a maximum of 10%E free sugar per day [2] in all age groups and in all years of observation. Descriptively, there seems also a stagnation in the median free sugar intake between 2020/2021 and 2022/2023. However, this stagnation cannot be confirmed based on the regression analyses. Therefore, our data indicate that the intake of free sugars among children and adolescents should continue to be monitored. Particular attention should be paid to critical ages, as in the present evaluation the median intake among 6- to 14-year-olds over the past 13 years is quite high at around 15%E. In addition, the available trends show that these age groups are most vulnerable to a high sugar intake: The age trend in free sugar intake between 2010 and 2023 is similar to the trend in 1985–2016 [3]. In both, the intake of free sugars per day increases continuously up to early adolescence and then decreases again. Although the differences between the intakes during primary school age and early adolescence are small. While in previous analyses the oldest participants showed the lowest intake of free sugars [3], in 2010–2023 it was the youngest (3/4 years) and oldest participants (17/18 years). This indicates an age and time interaction i.e. that the strength of the decline in free sugar intake varied depending on the age of the participants, which however could not be confirmed statistically in the current trend analyses.

The high sugar intake observed among children and adolescents supports the current sugar reduction measures of the German ministry. Until 2025, sugar reduction of at least 20% in breakfast cereals for children as well as of 15% each in sweetened dairy products for children and in soft drinks and fruit drinks with added sugar are envisaged [1]. Since previous data show, that the main free sugar source of children are sweets [10], it should be discussed whether the envisaged measures are sufficient to reduce intake to below 10% E/d or whether this food group should also be included in future measures. Especially, as the intake of free sugar could even be higher in representative samples.

A limitation of the present evaluation is the relatively high socioeconomic status of the DONALD participants, due to the comprehensive study design, limiting the generalizability of our observations to the general paediatric population in Germany [6]. To the best of our knowledge, representative data on the intake of free sugars among children and adolescents in Germany, which also includes families with a rather low socio-economic status, has not yet been published. It is possible that the intake of free sugars decreases less in this population group. However, socio-economic factors i.e. maternal educational status as well as employment status were taken into account as potential covariates in the present analysis. In contrast to our previous trend analyses [3], socioeconomic factors were not identified as confounders in the present analysis. Relevant confounding factors were number of weekdays per record and overweight status of the participants only. Both factors were already relevant in the earlier trend analysis on free sugar intake [3].

There are also several strengths to the current study and analysis that should be mentioned. The main strength of the DONALD study is its longitudinal design, allowing time and age trend analyses covering large time periods as well as the entire childhood and adolescence. The 3-day weighed dietary records and the continuously updated in-house nutrient database LEBTAB [5] allow the estimation of total, added and free sugar intake. Hence, the DONALD study is one of few studies, which can calculate data on free sugar intake. In addition, LEBTAB accounts for changes in recipes over time. If the recipe of a product was changed e.g. due to reformulation measures, a new entry was added to LEBTAB, whilst the entry for the product with the old recipe was marked, but retained in the database for dietary analyses. This consideration of recipe changes by industrial manufacturers in our nutrient database enables time trend analyses in dietary intake such as the present one.

In conclusion, free sugar intake continues to decline among children and adolescents in Germany, but still exceeds the WHO recommendation. Regardless of the observation years, children between 6 and 14 years of age appear to be particularly vulnerable to a high intake of free sugar. Our data support the relevance of the current political discussions on reducing sugar intake. Further measures, including the extension of reformulation measures to other food groups, the introduction of taxes on sugar sweetened beverages or the introduction of labels, which include sugar content limits, should be discussed.