EFFECT OF HYDROLYZED GUAR FIBER ON FASTING AND POSTPRANDIAL SATIETY AND SATIETY HORMONES - A DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL DURING CONTROLLED WEIGHT-LOSS

OBJECTIVE: To evaluate the effects of a completely soluble fiber on fa sting and postprandial hormone levels, respiratory quotient (RQ) and s ubjective ratings of satiety during a controlled weight-loss program. DESIGN: In a five-week prospective, randomized, double-blind study, a 3.3 MJ (800 kcal)/d diet was provided during a two-week wash-in period . Then, during the intervention weeks, separated by a one-week wash-ou t period, a 3.3 MJ (800 kcal) formula containing either 20 g fiber or placebo daily, was given in a cross-over design and on days 1, 3 and 7 of the intervention weeks (weeks 3 and 5) measurements were taken aft er an overnight fast. SUBJECTS: 25 obese but otherwise healthy females (age: 46 +/- 6 y, body mass index (BMI): 35 +/- 6 kg/m(2)) were studi ed. MEASUREMENTS: Body weight; hunger/satiety ratings; glucose, insuli n, cholecystokinin (CCK) and leptin concentrations; RQ during the inte rvention weeks. RESULTS: In the fasting state, the supplement had no e ffect on any of the measured parameters, including blood concentration s of glucose, insulin, CCK, and leptin, RO and satiety ratings. In the 2 h postprandial period following the test meal, none of the measured parameters differed significantly from that following the non-fiber-s upplemented meal, except for the CCK response. CCK demonstrated an ove rall higher concentration after the fiber-supplemented meal (P = 0.007 ), even after adjustment for age, weight, height and treatment sequenc e. The postprandial peak in CCK also occurred earlier (at 15 min vs 30 min) after completion of the fiber-supplemented meal. CONCLUSIONS: Th e results indicated that a hydrolyzed guar gum fiber supplement produc ed a heightened postprandial CCK response, but did not alter other sat iety hormones or increase satiety ratings, in either the fasting or th e postprandial state.