Physical properties of food may account for differences in glycemic and other metabolic responses to food with similar amounts of carbohydrate, fat and protein. Blending of cooked beans made no difference to plasma glucose, insulin, or GIP (gastric inhibitory polypeptide) responses in nondiabetics, NIDD (noninsulin-dependent diabetics), and IDD (insulin-dependent diabetics). The cooked blended beans gave a greater plasma glucose response and a lesser hormonal response than a cooked flummery (containing cornstarch, protein and fat) in nondiabetics. In NIDD and IDD, however, the reverse applied for plasma glucose. In nondiabetics, cooked flummery gave a lesser glycemic response at some time points than uncooked flummery. In NIDD the opposite occurred. Cooking led to no significant change in insulin response in nondiabetics, but to a lesser insulin response in NIDD. The effect of some physical properties of food on diabetic control cannot be inferred from findings in nondiabetics.