Outcome measure The percent of food purchased that was saturated fat. Results There were 497 randomised participants, mean age 40 each shopping for an average of about 3 people. The amount of saturated fat in the foods purchased by the intervention group was 0.66% lower (95% confidence interval 0.48-0.84, p<0.0001) than in the control group. The effects of the intervention were sustained over time and there was no difference in the average cost of the food bought by each group.