Effects of dietary intervention on food choice were studied in 240 women aged 50-65 years who had been operated for a stage I-II breast cancer. Following surgery, the women participated in a dietary history interview and were then randomized to one of two groups. The intervention group (n = 121) received individual dietary counselling aimed at reducing dietary fat intake to 20-25% energy (E%), whereas no dietary advice was given to women in the control group (n = 119). For the 52% of the women in the intervention group that completed the study the total fat intake decreased from 36 to 23 E% (P less than or equal to 0.01) and from 37 to 34 E% (P less than or equal to 0.01) for the control group. There were significant reductions in the intake of table fat, high-fat milk products, pork and sausages (containing greater than 11% fat), eggs, rice, pasta, cakes and chocolate for the intervention group. Concurrently the intake of vegetables, fruits, potatoes, bread, cereals, low-fat milk products, low-fat meat, sausages and fish increased significantly. For the control group there was a significant decrease in the consumption of total milk products, total meats, rice, pasta, cakes, and butter intake while the consumption of vegetables, fruits, cereals and fish increased (P less than or equal to 0.01). Reduction of high-fat foods and increases of carbohydrate-rich foods were more pronounced for the intervention group than for the control group. Formal education influenced dietary changes, and dietary counselling should therefore ideally be adapted to education level. This study showed that dietary counselling can bring about significant changes in consumption of high-fat foods for at least a 2-year period for women operated for breast cancer.