Fermentable Fibers Do Not Affect Satiety or Food Intake by Women Who Do Not Practice Restrained Eating

Background: Fiber is thought to enhance satiety, although not all fibers are equally effective. Colonic fermentation may influence satiety and food intake.

Objective: To test the satiating properties of four isolated fibers added to chocolate crisp bars.

Design: Within-subject preload design with repeated measures. Each participant completed five conditions, presented in random order.

Subjects: Participants were 22 adult women who do not practice restrained eating (body mass index 18 to 29).

Intervention: The experimental conditions were four fiber treatments: 10 g oligofructose, inulin, soluble corn fiber, or resistant wheat starch in chocolate crisp bars. A no-added-fiber bar was evaluated as the control. The night before each treatment, participants consumed a dinner bar containing 10 g of the same fiber given the next morning.

Main Outcome Measures: Repeated ratings of feelings related to hunger and fullness at the lunch meal were the main measures. Secondary outcomes included breath hydrogen and methane, gastrointestinal symptoms, energy consumed at an ad libitum lunch, and energy from 24-hour dietary recall.

Statistical Analyses Performed: Mixed-effect linear models with random intercept for participants to model within-subject correlation.

Results: All treatments were well tolerated. No differences were found in subjective satiety during the morning or food intake at lunch or over 24 hours. The oligofructose bar produced the greatest increase in breath hydrogen, and the most bloating and flatulence symptoms.

Conclusions: Functional fibers incorporated into chocolate bars at high fiber doses produce greater gastrointestinal symptoms than control, but do not alter satiety, hunger, or food intake compared with control in the short term.