Background: Increasing gastro-intestinal viscosity or colonic fermentation is suggested to help improve appetite control and reduce food intake. Beta-glucan (BG) and fructo-oligosaccharide (FOS) are food ingredients proposed to act this way, but results so far remain inconclusive.~Objective: To test the effect of FOS, BG, or their combination in bars on appetite ratings and food intake during 2 consecutive days.~Design: In a 4-way balanced order cross-over double-blind design, 21 healthy volunteers (mean BMI 25.9 kg/m2) received a meal replacement bar at 09.00h and an ad libitum lunch at 13.00h on 2 consecutive days. On day 1 only, subjects consumed a second (identical) bar at 17.00h and a fixed snack at 19.00h. The control bar contained 0.3g BG (control, from 6.8 g oats), vs equi-caloric bar formulations containing an additional: 1) 0.9 g BG (from 8.0g barley), 2) 8g FOS, or 3) 0.9 g BG + 8g FOS. Appetite scores and subsequent ad libitum test meal intakes were measured. Bar viscosities were determined under simulated gastric conditions. Results were analyzed using ANCOVA.~Results: Addition of BG, FOS or their combination did not affect appetite ratings or food intake, although addition of BG to the bar doubled apparent gastric viscosity (841 vs 351 mPa.s).~Conclusions: BG, FOS or their combination in bars at these levels do not improve appetite control when consumed on 2 consecutive days. Efficacy might be increased by a longer exposure period, increasing the BG content, or a form of BG that generates even higher gastric viscosity.
The effect of beta-glucan or fructo-oligosaccharide or their combination in bars on satiety and food intake was tested by supplying these bars on two consecutive days.