Twenty‐eight insulin dependent diabetics followed a simple diet, which involved avoiding concentrated highly refined carbohydrate foods and eating regular meals, for three months. For a further three months, they followed a diet which used a conventional carbohydrate exchange system. Mean HbA1 was 12.4% at the start of the study and fell to 11.5% after three months on a simple diet. No further significant improvement occurred after a further three months on the exchange diet (mean HbA1 11.3%). Seven‐day food records showed consistency of carbohydrate intake to be no greater on the carbohydrate exchange diet than on the simple diet. There was no significant difference between simple or exchange diets with respect to energy, carbohydrate, or dietary fibre intakes, or percentage energy from carbohydrate. The possibility of improving diabetic control by teaching a simple diet in conjunction with interpreting blood tests and insulin adjustment is discus