EFFECT OF MEAL DILUTION ON THE POSTPRANDIAL GLYCEMIC RESPONSE - IMPLICATIONS FOR GLYCEMIC TESTING

OBJECTIVE - To investigate the effect of varying the volume of sugar m eals on the postprandial glycemic response (PGR). RESEARCH DESIGN AND METHODS - On six separate occasions, after an overnight fast, blood gl ucose concentrations were measured in eight healthy subjects (34 +/- 4 years of age, BMI 22.9 +/- 0.9 kg/m(2)) after the consumption of 25 g glucose, sucrose, or fructose dissolved in either 200 or 600 ml of wa ter. Blood was obtained at fasting and then at times 15, 30, 45, 60, a nd 90 min after the start of the test meal. RESULTS - PGR was found to be influenced by carbohydrate type (P < 0.001). Mean response areas ( min.mmol.l(-1)) to the three sugars were statistically different (P < 0.05). Glucose had the highest response area (90.0 +/- 8.1), followed by sucrose (61.3 +/- 5.0) and then fructose (14.7 +/- 2.8). Independen t of this effect, PGR was also found to be influenced by volume dose ( P < 0.01). By tripling meal volume from 200 to 600 ml, PGR areas were significantly increased for all three sugars, glucose (79.3 +/- 10.3 v s. 100.8 +/- 12.0, P = 0.035), sucrose (52.6 +/- 5.5 vs. 70 +/- 7.4, P = 0.0094), and fructose (11.0 +/- 3.8 vs. 18.4 +/- 3.9, P = 0.012). W here the effects of time (P < 0.05) and dose (P < 0.05) were determine d to be independent (interaction nonsignificant) for all three sugars, this increase in volume also significantly increased glycemic concent rations at 15 min, for glucose (P = 0.033) and sucrose (P = 0.026), su ggesting that changes in gastric emptying time may be a mechanism of a ction. CONCLUSIONS - Varying the volume of liquid sugar meals alters P GR. Understanding this concept may help to reduce variability both in the glycemic testing of foods and oral glucose tolerance testing.