The study aimed to evaluate the impact of a 15-month intervention on dietary intake conducted among obesity-prone normal-weight pre-school children. Information on dietary intake was obtained using a 4 d diet record. A diet quality index was adapted to assess how well children’s diet complied with the Danish national guidelines. Linear regression per protocol and intention-to-treat analyses of differences in intakes of energy, macronutrients, fruit, vegetables, fish, sugar-sweetened beverages and diet quality index between the two groups were conducted. The Healthy Start study was conducted during 2009–2011, focusing on changing diet, physical activity, sleep and stress management to prevent excessive weight gain among Danish children. From a population of 635 Danish pre-school children, who had a high birth weight (≥4000 g), high maternal pre-pregnancy BMI (≥28·0 kg/m2) or low maternal educational level (<10 years of schooling), 285 children completed the intervention and had complete information on dietary intake. Children in the intervention group had a lower energy intake after the 15-month intervention (group means: 5·29 v. 5·59 MJ, P=0·02) compared with the control group. We observed lower intakes of carbohydrates and added sugar in the intervention group compared with the control group after the intervention (P=0·002, P=0·01). The intervention resulted in a lower energy intake, particularly from carbohydrates and added sugar after 15 months of intervention, suggesting that dietary intake can be changed in a healthier direction in children predisposed to obesity.