Introducing nutritional principles of preventive cardiology to the care of young children may improve permanently adherence to a low-saturated-fat, low-cholesterol diet later in life. This approach has not been readily adapted because of worries of the possible effects of such a diet on the growth and development of children. In the STRIP baby project, 1062 infants were randomized at 7 months of age into an intervention group (n = 540) or a control group (n = 522). The counselling of the intervention children aimed at a fat intake of 30% of energy after the age of 1 year and to a 1:1:1 ratio in saturated:monounsaturated:polyunsaturated fat intake. Dietary intake, growth and serum lipid concentrations were monitored in the children regularly through the first years of life. The intake of total fat, saturated fat and cholesterol were lower and the intake of polyunsaturated fat and the ratio of polyunsaturated to saturated fat (P/S) in the diet were higher in the intervention children than in the controls. During the first 3 years of the trial, the serum cholesterol concentration was 3-6% lower in the intervention children than in the controls (95% CI for the mean difference between groups from -0.27 to -0.12 mmol/L). No differences in the growth of the children were observed between the groups. We conclude that repeated individualized counselling aiming at reduced consumption of saturated fat combined with regular follow-up is effective and does not restrict the growth of children.