Fiber-enriched processed foods promise a healthier version of snacks, but they might not keep hunger at bay….
The researchers found no hunger-limiting effects of chocolate bars containing four different "functional fibers," such as inulin (aka "chicory root extract") commonly found in fiber-enriched processed foods.
Overall, the women in the study were just as hungry come lunch time as they were on a day when they ate a low-fiber bar for breakfast. And their food intake for the rest of the day was similar as well.
Senior researcher Joanne Slavin, a registered dietitian and professor at the University of Minnesota in St. Paul, added that, "In general, added fibers don’t work across the board when it comes to helping you feel fuller longer." "That doesn’t mean people shouldn’t eat fiber-enriched foods." She added, "It’s hard to get people to eat enough fiber, it’s one of our shortfall nutrients." "I think putting fiber into foods that people will actually eat is a good thing."
"It would be nice if these foods had an effect on satiety," Slavin added. On the other hand, she noted, they may still help regulate bowel habits or control cholesterol.
For the study, Slavin’s team recruited 22 young women who were not trying to lose weight. They had each woman eat five different chocolate crisp bars on separate days; four of the bars had one of four added fibers, while the fifth one had no extra fiber.
The women had one bar in the evening and then a bar for breakfast the next morning. They then had lunch at the research lab, where they rated their fullness and hunger on a standard scale. After that, they used diaries to record their food intake for the rest of the day.
Overall, Slavin’s team found, there were no differences in the women’s hunger ratings or food intake with the fiber-rich bars versus the low-fiber one. The fiber did, however, cause more gas and bloating.
It’s a common perception that extra fiber fills you up longer. But according to Slavin, subjective feelings of fullness may go beyond the fiber itself.
In one study, she and her colleagues found that a breakfast of oatmeal and fruit was more satisfying to people than a liquid breakfast with the same fiber content.
Slavin said she thinks it’s the total experience of eating fiber-rich foods – the chewing, the sight of a big bowl of oatmeal – that makes people feel more satisfied. "You really know you’re eating fiber," she said.
With a fiber-added chocolate bar, the experience is different. "With these products, it’s like eating a brownie," Slavin said.
Journal of the Academy of Nutrition and Dietetics, July, 2012