Numerous methods have been evolved for the calculation of diets to be used by patients with diabetes mellitus and for the simplified instruction of patients in the use of such diets. Some of these methods involve calculations which are unnecessarily accurate in view of the variable composition of foods, as affected by such factors as the variety of seed, the soil, climatic conditions and harvesting, storage and cooking methods. The fairly common practice of instructing patients to weigh diets can be criticized for the same reason plus the fact that a patient who is "tied to a pair of scales" has much less chance of living a normal life, which is so important from a psychologic point of view. The subject of the percentage of carbohydrate in foods, particularly vegetables, has also been confusing to the patient. In general, we have found that many patients disregarded it and ate whatever