OBJECTIVE: It is debated whether the intake of added sugar displaces micronutrient-rich foods and dilutes the nutrient density of the diet, and whether there is a link between sugar and the increased rate of obesity. The objectives of this study were to examine the effect of added sugar on the intakes of energy, micronutrients, fruit and vegetables, and to examine the association between intake of added sugar and age, sex, body mass index, physical activity, inactivity and parents' education. DESIGN: Participants recorded their food intake in pre-coded food diaries for 4 days and filled in a questionnaire about physical activity, watching television (TV)/using a personal computer (PC) and parents' education. SUBJECTS: Three hundred and ninety-one 4-year-olds, 810 students in the 4th grade (9 years old) and 1005 in the 8th grade (13 years old) were included in the study. RESULTS: The intakes of all nutrients, except alpha-tocopherol among 4-year-olds and vitamin C among 4-year-olds and 4th graders, decreased with increasing content of added sugar in the diet. Moreover, high consumers of added sugar had a 30-40% lower intake of fruit and vegetables than did low consumers. A negative association was observed between consumption of added sugar and body mass index among girls in the 8th grade (P=0.013), whereas a positive association was observed among 4-year-old boys (P=0.055). Associations between physical activity, hours spent watching TV/using a PC, parents' education and the energy intake from added sugar varied in the different age groups. CONCLUSIONS: This study showed a negative association between the intake of added sugar and intakes of micronutrients, fruit and vegetables. The negative association between sugar intake and intake of fruit and vegetables is important from a public health perspective, since one of the main health messages today is to increase current intake of fruit and vegetables.