Experimental procedures Using standard methodology to determine a food’s Gl value, a portion of the food containing between 10 and 50 grams of available carbohydrate is fed to 10 healthy people the morning after they have fasted for 10-12 hours overnight. A fasting blood sample is first obtained from each person and then the food is consumed, after which additional blood samples are obtained at regular intervals during the next two hours. In this way, it’s possible to measure the total increase in blood sugar produced by that food over a two-hour period. The two-hour blood glucose (glycaemic) response for this test food is then compared to the two-hour blood glucose response produced by the same amount of carbohydrate in the form of pure glucose sugar (the reference food: Gl value of glucose = 100%). Therefore, Gl values for foods and drinks are relative measures (ie they indicate how high blood sugar levels rise after eating a particular food compared to the very high blood sugar response produced by the same amount of carbohydrate in the form of glucose sugar). Equal-carbohydrate portions of test foods and the reference food are used in Gl experiments, because carbohydrate is the main component in food that causes the blood’s glucose level to rise. The night before each test session, the subjects ate a regular low-fat evening meal based on a carbohydrate-rich food, other than legumes, and then fasted for at least 10 hours overnight. The subjects were also required to avoid alcohol and unusual levels of food intake and physical activity for the whole day before each test session. Measurement of the subjects’ blood glucose responses For each subject, the concentration of glucose in each of the eight whole blood samples collected from them during each test session was analysed in duplicate using a HemoCue fi B-glucose photometric analyser employing a glucose dehydrogenase / mutarotase enzymatic assay (HemoCue AB, Angelholm, Sweden). Each blood sample was collected into a plastic HemoCue fi cuvette containing the enzymes and reagents for the blood glucose assay and then placed into the HemoCue analyser while the enzymatic reaction took place. Therefore, each blood sample was analysed immediately after it was collected. For each of the 10 subjects, a two-hour blood glucose response curve was constructed for each of their test sessions using the average blood glucose concentrations for each of their eight blood samples. The two fasting blood samples were averaged to provide one baseline glucose concentration. The area under each two-hour blood glucose