To compare differences in children's diet quality on weekdays (Monday–Thursday), Fridays and weekend days.

A representative cross-sectional study in which participants completed a 7 d pre-coded food record. Mean intakes of energy, macronutrients and selected food items (g/10 MJ) as well as energy density were compared between weekdays, Fridays and weekend days for each gender in three age groups (4–6, 7–10 and 11–14 years) using Tobit analysis to account for zero intakes.

The Danish National Survey of Dietary Habits and Physical Activity 2003–2008.

Children (n 784; 49·9 % boys) aged 4–14 years.

For both genders in all age groups (P < 0·05), energy intake was higher during weekends than on weekdays, and intakes of sugar-sweetened beverages and white bread were higher, whereas intake of rye bread was lower. This contributed to a higher percentage of energy from added sugars, a lower fibre content and a higher energy density on weekend days v. weekdays. In children aged 4–6 and 7–10 years, the diet on weekend days was also characterized by higher intakes of sweets and chocolate and lower intakes of fruit and vegetables. Overall, the diet on Fridays appeared as a mix of the diets on weekdays and weekend days.

Significant differences and distinct characteristic patterns were found in children's diet quality during weekdays, Fridays and weekend days. The present study suggests that in prevention of childhood overweight and obesity, more attention should be paid to the higher energy intake, especially from sugar-rich foods and beverages, on Fridays and weekend days.