In an attempt to apply the concept of glycemic index (GI) and insulinemic index (II) to local eating habits, we examined the plasma glucose and insulin responses in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and healthy subjects to five mixed meals of different ethnic origins. All meals contained 50 g carbohydrate and were compared with a 50-g glucose load. The GI was highest for the Polish dish and lowest for the Syrian dish (66 +/- 5.5 vs 24 +/- 5.1). However, the II was the highest for the standard meal and lowest again for the Syrian dish (174 +/- 27 vs 66 +/- 25). A high correlation was found between the area under the glucose curve and the predicted GI in both NIDDM and healthy subjects. The GI concept is valid and potentially useful in diet planning and legume foods should be incorporated as a carbohydrate source when diets are being planned for NIDDM subjects or individuals with impaired glucose tolerance.