The European Food Safety Authority has suggested that EU countries implement the 2 × 24 h diet recall (2 × 24 h DR) method and physical activity (PA) measurements for national dietary surveys. Since 2000, Denmark has used 7 d food diaries (7 d FD) with PA questionnaires and measurements. The accuracy of the reported energy intakes (EI) from the two diet methods, pedometer-determined step counts and self-reported time spent in moderate-to-vigorous PA (MVPA) were compared with total energy expenditure measured by the doubly labelled water (TEEDLW) technique and with PA energy expenditure (PAEE), respectively. The study involved fifty-two male and sixty-eight female volunteers aged 18–60 years who were randomly assigned to start with either the 24 h DR or the web-based 7 d FD, and wore a pedometer for the first 7 d and filled in a step diary. The mean TEEDLW (11·5 MJ/d) was greater than the mean reported EI for the 7 d FD (9·5 MJ/d (P < 0·01)) but the same as the 2 × 24 h DR (11·5 MJ/d). The proportion of under-reporters was 34 % (7 d FD) and 4 % (2 × 24 h DR). Most participants preferred the 7 d DR as it was more flexible, despite altering their eating habits. Pearson’s correlation between steps corrected for cycling and PAEE was r = 0·44, P < 0·01. Spearman’s correlation for self-reported hours spent in MVPA and PAEE was r = 0·58, P < 0·01. The 2 × 24 h DR performs better than the existing 7 d FD method. Pedometer-determined steps and self-reported MVPA are good predictors of PAEE in adult Danes.

Associations between meat consumption and heart disease have been assessed in several studies, but it has been suggested that other dietary factors influence these associations. The aim of the present study was to assess whether meat consumption is associated with ischaemic heart disease (IHD), and if the association is modified by dietary quality. The analyses were based on the cohort of adult participants in the Danish National Survey on Diet and Physical Activity in 2000–2002, 2003–2008 and 2011–2013. From these surveys, information on meat consumption and dietary quality was extracted. The cohort was followed in national registers to identify incident IHD. Associations were estimated using Cox regression analyses adjusting for socio-demographic and lifestyle factors. Analyses of associations between meat consumption and IHD stratified by dietary quality were subsequently evaluated. Among the 8007 participants, the median follow-up was 9·8 years and 439 cases of IHD were recorded. The results suggested a trend between consumption increments of 100 g/d of red meat (hazard ratio (HR) = 1·23; 95 % CI 0·99, 1·53) or of 50 g/d of processed meat (HR = 1·09; 95 % CI 0·93, 1·29) and higher risk of IHD. The trends were, however, not statistically significant. Stratification by dietary quality did not suggest that associations between meat consumption and risk of IHD were modified by dietary quality. This population-based cohort study with detailed dietary information suggested a trend with higher meat consumption being associated with higher risk of IHD, but the association was not statistically significant. Results did not indicate that dietary quality modifies such associations.

A child's diet is an important determinant for later health, growth and development. In Denmark, most children in primary school bring their own packed lunch from home and attend an after-school care institution. The aim of the present study was to evaluate the food, energy and nutrient intake of Danish school children in relation to dietary guidelines and nutrient recommendations, and to assess the food intake during and outside school hours. In total, 834 children from nine public schools located in the eastern part of Denmark were included in this cross-sectional study and 798 children (95·7 %) completed the dietary assessment sufficiently (August–November 2011). The whole diet was recorded during seven consecutive days using the Web-based Dietary Assessment Software for Children (WebDASC). Compared with the food-based dietary guidelines and nutrient recommendations, 85 % of the children consumed excess amounts of red meat, 89 % consumed too much saturated fat, and 56 % consumed too much added sugar. Additionally 35 or 91 % of the children (depending on age group) consumed insufficient amounts of fruits and vegetables, 85 % consumed insufficient amounts of fish, 86 % consumed insufficient amounts of dietary fibre, 60 or 84 % had an insufficient Fe intake (depending on age group), and 96 % had an insufficient vitamin D intake. The study also showed that there is a higher intake of fruits and bread during school hours than outside school hours; this is not the case with, for example, fish and vegetables, and future studies should investigate strategies to increase fish and vegetable intake during school hours.

A New Nordic Diet (NND) was developed in the context of the Danish OPUS Study (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet). Health, gastronomic potential, sustainability and Nordic identity were crucial principles of the NND. The aim of the present study was to investigate the effects of serving NND school meals compared with the usual packed lunches on the dietary intake of NND signature foods. For two 3-month periods, 834 Danish children aged 8–11 years received NND school meals or their usual packed lunches brought from home (control) in random order. The entire diet was recorded over 7 consecutive days using a validated Web-based Dietary Assessment Software for Children. The NND resulted in higher intakes during the entire week (% increase) of root vegetables (116 (95 % CI 1·93, 2·42)), cabbage (26 (95 % CI 1·08, 1·47)), legumes (22 (95 % CI 1·06, 1·40)), herbs (175 (95 % CI 2·36, 3·20)), fresh berries (48 (95 % CI 1·13, 1·94)), nuts and seeds (18 (95 % CI 1·02, 1·38)), lean fish and fish products (47 (95 % CI 1·31, 1·66)), fat fish and fish products (18 (95 % CI 1·02, 1·37)) and potatoes (129 (95 % CI 2·05, 2·56)). Furthermore, there was a decrease in the number of children with zero intakes when their habitual packed lunches were replaced by NND school meals. In conclusion, this study showed that the children increased their intake of NND signature foods, and, furthermore, there was a decrease in the number of children with zero intakes of NND signature foods when their habitual packed lunches were replaced by school meals following the NND principles.

Bias in self-reported dietary intake is important when evaluating the effect of dietary interventions, particularly for intervention foods. However, few have investigated this in children, and none have investigated the reporting accuracy of fish intake in children using biomarkers. In a Danish school meal study, 8- to 11-year-old children (n 834) were served the New Nordic Diet (NND) for lunch. The present study examined the accuracy of self-reported intake of signature foods (berries, cabbage, root vegetables, legumes, herbs, potatoes, wild plants, mushrooms, nuts and fish) characterising the NND. Children, assisted by parents, self-reported their diet in a Web-based Dietary Assessment Software for Children during the intervention and control (packed lunch) periods. The reported fish intake by children was compared with their ranking according to fasting whole-blood EPA and DHA concentration and weight percentage using the Spearman correlations and cross-classification. Direct observation of school lunch intake (n 193) was used to score the accuracy of food-reporting as matches, intrusions, omissions and faults. The reporting of all lunch foods had higher percentage of matches compared with the reporting of signature foods in both periods, and the accuracy was higher during the control period compared with the intervention period. Both Spearman's rank correlations and linear mixed models demonstrated positive associations between EPA+DHA and reported fish intake. The direct observations showed that both reported and real intake of signature foods did increase during the intervention period. In conclusion, the self-reported data represented a true increase in the intake of signature foods and can be used to examine dietary intervention effects.

The aim of the present study was to compare total food intake, total and relative edible plate waste and self-reported food likings between school lunch based on the new Nordic diet (NND) and packed lunch from home. In two 3-month periods in a cluster-randomised controlled unblinded cross-over study 3rd- and 4th-grade children (n 187) from two municipal schools received lunch meals based on NND principles and their usual packed lunch (control). Food intake and plate waste (n 1558) were calculated after weighing lunch plates before and after the meal for five consecutive days and self-reported likings (n 905) assessed by a web-based questionnaire. Average food intake was 6 % higher for the NND period compared with the packed lunch period. The quantity of NND intake varied with the menu (P < 0·0001) and was positively associated with self-reported likings. The edible plate waste was 88 (sd 80) g for the NND period and 43 (sd 60) g for the packed lunch period whereas the relative edible plate waste was no different between periods for meals having waste (n 1050). Edible plate waste differed between menus (P < 0·0001), with more waste on soup days (36 %) and vegetarian days (23 %) compared with the packed lunch period. Self-reported likings were negatively associated with percentage plate waste (P < 0·0001). The study suggests that portion sizes need to be considered in new school meal programmes. New strategies with focus on reduction of plate waste, children's likings and nutritious school meals are crucial from both a nutritional, economic and environmental point of view.

The OPUS (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (NND)) School Meal Study investigated the effects on the intake of foods and nutrients of introducing school meals based on the principles of the NND covering lunch and all snacks during the school day in a cluster-randomised cross-over design. For two 3-month periods, 834 Danish children aged 8–11 years from forty-six school classes at nine schools received NND school meals or their usual packed lunches brought from home (control) in random order. The whole diet of the children was recorded over seven consecutive days using a validated Web-based Dietary Assessment Software for Children. The NND resulted in higher intakes of potatoes (130 %, 95 % CI 2·07, 2·58), fish (48 %, 95 % CI 1·33, 1·65), cheese (25 %, 95 % CI 1·15, 1·36), vegetables (16 %, 95 % CI 1·10, 1·21), eggs (10 %, 95 % CI 1·01, 1·19) and beverages (6 %, 95 % CI 1·02, 1·09), and lower intakes of bread (13 %, 95 % CI 0·84, 0·89) and fats (6 %, 95 % CI 0·90, 0·98) were found among the children during the NND period than in the control period (all, P< 0·05). No difference was found in mean energy intake (P= 0·4), but on average children reported 0·9 % less energy intake from fat and 0·9 % higher energy intake from protein during the NND period than in the control period. For micronutrient intakes, the largest differences were found for vitamin D (42 %, 95 % CI 1·32, 1·53) and iodine (11 %, 95 % CI 1·08, 1·15) due to the higher fish intake. In conclusion, the present study showed that the overall dietary intake at the food and nutrient levels was improved among children aged 8–11 years when their habitual packed lunches were replaced by school meals following the principles of the NND.

A negative association between sleep duration and BMI has been observed in children. However, knowledge about the association between sleep duration and diet is limited. The objective was to examine the association between sleep duration and intake of foods and nutrients in children. In the present cross-sectional study, dietary intake and sleep duration were recorded by the parents for seven consecutive days in a food and sleep record in a representative sample of 802 4- to 14-year-old children. No sex differences were found regarding age and sleep duration. Sleep duration was negatively correlated to age (ρ = –0·68; P < 0·001) and BMI (ρ = –0·41; P < 0·001). In multiple linear regression analyses, sleep duration was not associated with energy intake (b = –0·015; P = 0·20), but there was a trend towards a positive association with intake of dietary fibre (b = 0·006; P = 0·05) and vegetables (b = 0·011; P = 0·05), and a negative association with intake of poultry (b = –0·002; P = 0·02), and a trend towards a negative association with intake of liquid ‘discretionary calories’ (b = –0·01; P = 0·05). Furthermore, in a comparison of dietary intake between age-dependent tertiles of sleep duration, only intake of liquid ‘discretionary calories’ was significantly lower in long sleepers than in short and medium sleepers (P = 0·03). In conclusion, sleep duration was not associated with energy intake and the proposal that children with short sleep duration have less healthy eating habits than children with longer sleep duration was only weakly supported by the present findings.

Dietary n-3 long-chain PUFA (LC-PUFA) improve dyslipidaemia and hypertension and may affect insulin resistance and adiposity. Increasing numbers of children show signs of the metabolic syndrome (MetS), but few studies have investigated the association with n-3 LC-PUFA status. We examined the relationship between fasting whole-blood EPA or DHA (w/w% of the total fatty acids, FA%) and markers of the MetS (anthropometry, blood pressure, plasma lipids and glucose homeostasis) cross-sectionally in seventy-three 8–11-year-old Danish children from the OPUS School Meal Pilot Study (OPUS is an acronym of the project ‘Optimal well-being, development and health for Danish children through a healthy New Nordic Diet’ and is supported by a grant from the Nordea Foundation). Also, we explored the potential mediating effects of physical activity and energy intake. Girls had higher body fat percentage (BF%), diastolic blood pressure, heart rate, plasma TAG, insulin, homeostasis model assessment-insulin resistance and glycosylated Hb than boys. Sexes did not differ in fish or macronutrient intake or whole-blood fatty acids. After adjustment for sex, age and total whole-blood fatty acid concentration, BF% and HDL:TAG increased with whole-blood EPA (β>0·25, P< 0·05), and HDL increased 0·35 (sem 0·13) mmol/l per FA% EPA increase (β = 0·30, P= 0·008). Unexpectedly, DHA was positively associated with mean arterial pressure in boys (6·3 (sem 1·7) mmHg/FA% DHA increase, β = 0·62, P= 0·001) and reduced physical activity in both sexes ( − 44 (sem 19) counts/min per FA%, β = − 0·22, P= 0·024). The associations with blood pressure and HDL remained after adjustment for physical activity, BF% and energy intake. The present study confirmed the beneficial association between n-3 LC-PUFA status and lipid profile seen in adults, but showed unexpected relationships with physical activity, BF% and blood pressure. This is the third time we have observed such tendencies in Danish children.

Web-based Dietary Assessment Software for Children (WebDASC) was developed to estimate dietary intake in a school meal intervention study among 8- to 11-year-old Danish children. The present study validates self-reported fruit, juice and vegetable (FJV) intakes in 8- to 11-year-old children by comparing intake with plasma carotenoid concentration, and by comparing the reported FJV intake to actually eaten FJV, as observed by a photographic method. A total of eighty-one children, assisted by parents, reported their diet for seven consecutive days. For the same five schooldays as they reported their diet, the children's school lunch was photographed and weighed before and after eating. In the week after the diet reporting, fasting blood samples were taken. Self-reported intake of FJV and estimated intake of carotenoids were compared with plasma carotenoid concentration. Accuracy of self-reported food and FJV consumption at school lunch was measured in terms of matches, intrusion, omission and faults, when compared with images and weights of lunch intake. Self-reported intake of FJV was significantly correlated with the total carotenoid concentration (0·58) (P< 0·01). Fruit and juice consumption showed higher correlations than vegetables with plasma carotenoid concentration (0·38 and 0·42 v. 0·33) (P< 0·01). A total of 82 % of the participants fell into the same or adjacent quartiles when cross-classified by FJV intake and carotenoids biomarkers. WebDASC attained 82 % reporting matches overall and a higher percentage match for reporting fruits compared with beverages. The present study indicated that WebDASC can be used to rank 8- to 11-year-old Danish children according to their intake of FJV overall and at school meals.