Background. Established methods for measuring insulin responses to nutrients have usually used relatively invasive indwelling-catheters and technically complex radioimmunoassay (RIA) methods, which has limited the scope of application of insulin measurements. Snacking is an increasingly important part of the American caloric consumption, but insulin responses to diet are generally reported for meal-sized food portions (200-300 kCal). Objective. We sought to develop a facile insulin measurement method, collecting blood samples by fingerstick and measuring insulin with precise enzyme-linked-immunoassay (ELISA). We sought to demonstrate the method by determining insulin and glucose responses to 100 kCal snack portions in fasting subjects. Design. Six healthy adult subjects each consumed 7 different snack foods on separate days containing about 100 kCal/portion. Insulin and glucose levels were measured at 0 min, 30 min, and 60 min. Results. A donut portion (1/2 of a glazed donut) led to strong changes in insulin and glucose; a glass of skim milk, an apple and oatmeal changed insulin; wrinkled peas showed a lower glucose response than smooth peas, and walnuts led to minimal changes in either variable. Conclusions. The methodology described is simple and economical, is extremely precise, and can be used in many settings. A wide variety of different snacks can be studied conveniently in the same individuals, and the methodology could be applied to children. Guidance on snacks that will lead to little or no insulin elevation is desirable for individuals seeking successful weight-loss or weight maintenance regimens, since elevated insulin suppresses the mobilization of stored triglycerides for energy and stimulates the conversion of carbohydrate to fat.