Health benefits of viscous fiber intake are well established; nevertheless few effective and palatable preparations are available. The objective of the study therefore was to determine palatability and effectiveness of escalating doses of PGX, a novel viscous polysaccharide (NVP), in reducing postprandial glycemia when added to a liquid and a solid meal. Two open-label, randomized, controlled trials were undertaken. Glycemic Index Laboratories, Inc, Toronto, Ontario, Canada. Two groups of 10 healthy subjects each (group 1: 5 M, 5 F; 35.6 +/- 13.2 y; 24.6 +/- 2.1 kg/m(2); and group 2: 3 M, 7 F; 33.5 +/- 11.1 y; 26.3 +/- 5.2 kg/m(2)) were studied. Zero, 2.5, 5, and 7.5 g of NVP were added to a glucose drink (group 1) or to white bread and margarine (WB + Marg) (group 2). Subjects repeated glucose control (group 1) or WB control (group 2) 3 times to allow calculation of the glycemic index (GI). Measures of Outcomes: Palatability of foods and capillary blood glucose concentrations were measured fasting and at 15, 30, 45, 60, 90, and 120 minutes after the start of the meal. Addition of NVP to the meal reduced blood glucose incremental areas under the curve irrespective of dose, reaching significance at the 7.5 g dose when added to glucose (p < 0.01), and at the 5 and 7.5 g doses when added to WB + Marg (p < 0.001). The GI values of glucose with 0, 2.5, 5, or 7.5 g of NVP were (mean +/- standard error of the mean [SEM]) 100.0 +/- 0.0, 83.7 +/- 9.0, 77.7 +/- 8.2, and 72.5 +/- 5.9, respectively; the GI of the WB alone, or of WB + Marg, with 0, 2.5, 5, or 7.5 g of NVP was 71.0 +/- 0.0, 66.8 +/- 3.0, 47.5 +/- 5.9, 37.3 +/- 5.9, and 33.9 +/- 3.6, respectively. Addition of NVP to different food matrices is highly effective in lowering the glycemic index of a food in a dose-responsive manner.