Forty patients with non-insulin-dependent diabetes mellitus (NIDDM) were investigated regarding their individual diet history, including dietary pattern and dietary habits. The energy intake in men was 2,180 +/- 460 kcal/day. The carbohydrate content was 192 +/- 57 g/day (38 +/- 7%), protein 93 +/- 20 g/day (19 +/- 3%) and fat 96 +/- 26 g/day (43 +/- 7%). Nutritional intake of saturated fatty acids was 37 +/- 11 g/day, whereas the intake of polyenic acid was 14 +/- 5 g/day. Thus the p/s-quotient was 0.4 +/- 0.1. The cholesterol intake amounted to 396 +/- 165 mg/day. The dietary fibre content was 33 +/- 21 g/day. The caloric intake of women was 1,800 kcal/day. The daily amount of carbohydrate was 154 +/- 46 g/day (37 +/- 6%), of protein 82 +/- 21 g/day (20 +/- 4%), of fat 82 +/- 32 g/day (43 +/- 6%). Saturated fatty acids were 33 +/- 14 g/day, polyenic acid 11 +/- 5 g/day, the p/s-quotient 0.4 +/- 0.2. The cholesterol intake was calculated to be 341 +/- 118 mg/day. The supply of electrolytes, trace elements and vitamins was often marginal. We found that usually practiced diabetes diet is too fatty, rich in cholesterol and poor in carbohydrate and fibre. As a result of the high amount of fat, which comprises 43% of the total calories and the low p/s-quotient of 0.4, the diet must be considered atherogenic.