A new study out of the University of Calgary has found that rats given fibre supplements stay much slimmer than their peers — even when they binge on junk food.

Researchers studied three groups of rats which were fed:

  • Regular rat chow with no fibre supplements.
  • A high-fat, high-sugar diet with no fibre supplements.
  • A high-fat, high-sugar diet with fibre supplements.

Just like humans, some rats are more likely to gain weight while others will remain lean no matter how much sugar or fat they eat.

But to the researchers' surprise, that didn't play a role in outcome of the study.

"Regardless of their genetic makeup, whether they were prone or resistant to becoming obese naturally, the dietary fibre had really quite remarkable benefits," said Raylene Reimer, who is one of the authors of the study published in the April edition of the journal Obesity.

Animals given fibre supplements had 35 per cent less weight gain than those who were not given fibre supplements.

Prebiotic fibre

The rats were given oligofructose, which is a type of dietary prebiotic fibre found naturally in onions and bananas. 

According to the Journal of Nutrition oligofructose is not digested in the upper gastrointestinal tract, and therefore has a reduced caloric value. It also stimulates the growth of good bacteria in your belly.


Rats given an oligofructose fibre supplement gained about one third less weight than the control group. (Reuters)

"This fibre can increase the hormones in the body that help you feel fuller when you eat, so it's really good at regulating appetite," Reimer told the Calgary Eyeopener on Wednesday. 

Inulin is another prebiotic fibre you will often see on the ingredient list of cereals, granola bars and some yogurts sold in grocery stores.

Reimer, who is also a registered dietitian, says typically these foods have very low levels of inulin and oligofructose. To get the weight-loss benefits of prebiotic fibre, you need to take it in a supplement form. 

Can fibre solve obesity?

"It is not a 'magic bullet'," Reimer said in a release.

"If you take prebiotic fibre, it doesn't cause you to lose 100 pounds in six months."

But Reimer says it could help with obesity prevention, especially morbid obesity.

In a 2009 human study led by Reimer, adults receiving supplements of oligofructose lost on average one kilogram over a 12-week period.

They also did not continue to gain weight, which is what occurred among the participants who took the placebo.