Effect of hydrolyzed guar fiber on fasting and postprandial satiety and satiety hormones: A double-blind, placebo-controlled trial during controlled weight loss

Abstract

OBJECTIVE: To evaluate the effects of a completely soluble fiber on fasting and postprandial hormone levels, respiratory quotient (RQ) and subjective 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-out 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 after an overnight fast. SUBJECTS: 25 obese but otherwise healthy females (age: 46 ± 6 y, body mass index (BMI): 35 ± 6 kg/m2) were studied. MEASUREMENTS: Body weight; hunger/satiety ratings; glucose, insulin, cholecystokinin (CCK) and leptin concentrations; RQ during the intervention weeks. RESULTS: In the fasting state, the supplement had no effect on any of the measured parameters, including blood concentrations of glucose, insulin, CCK, and leptin, RQ 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-supplemented meal, except for the CCK response. CCK demonstrated an overall higher concentration after the fiber-supplemented meal (P = 0.007), even after adjustment for age, weight, height and treatment sequence. The postprandial peak in CCK also occurred earlier (at 15 min vs 30 min) after completion of the fiber-supplemented meal. CONCLUSIONS: The results indicated that a hydrolyzed guar gum fiber supplement produced a heightened postprandial CCK response, but did not alter other satiety hormones or increase satiety ratings, in either the fasting or the postprandial state.