British scientists have developed an ingredient that makes foods more filling, and say initial tests in overweight people showed that it helped prevent them gaining more weight.
The ingredient, developed by researchers at London's Imperial College and at the University of Glasgow, contains propionate, a natural substance that stimulates the gut to release hormones that act on the brain to reduce hunger.
Propionate is produced naturally when fiber in the diet is fermented by microbes in the gut, but the new ingredient, inulin-propionate ester (IPE), provides much larger amounts of propionate than people can generate in a normal diet.
"Molecules like propionate stimulate the release of gut hormones that control appetite, but you need to eat huge amounts of fiber to achieve a strong effect," said Gary Frost of Imperial's department of medicine, who led the study.
"We wanted to find a more efficient way to deliver propionate to the gut."
In a study published in the journal Gut, Frost's team gave 20 volunteers either IPE or inulin, a dietary fiber, and then allowed them to eat as much as they liked from a buffet.
The team found that those given IPE ate 14 percent less on average and had higher concentrations of appetite-reducing hormones in their blood.
In a second phase, 60 overweight volunteers took part in a 24-week study in which half were given IPE powder to add to their food and half given inulin.
Only one out of 25 volunteers given IPE who completed the study gained more than 3.0 percent of their body weight, compared with six out of 24 given inulin.
None of the IPE group gained more than 5.0 percent of their body weight, compared with four in the inulin group.
After 24 weeks, the IPE group also had less fat in their abdomens and livers compared with the inulin group.
Frost said that while the findings were only from a small, early-stage study, they offered "encouraging signs" that IPE might help prevent weight gain in overweight people.
He and his team are working with Imperial Innovations, a technology commercialization company focused on developing promising British academic research, on taking IPE to market.
"We're exploring what kinds of foods it could be added to, but something like bread or fruit smoothies might work well," he said.