Big Way Of Life

A new study has found that rats fed on crisps containing a fat substitute became more prone to weight gain than rats fed on full fat crisps.

Fat substitutes may actually cause people to gain weight, according to new research carried out at Purdue University in the US. This research comes on the back of previous research that indicated artificial sweeteners may also be linked to weight gain.

In the new study, one sample of rats was fed on a mix of full fat and reduced fat Pringles while another sample was fed on only full fat Pringles. The researchers found that the rats fed on the mixture of high and low fat Pringles actually gained more weight than the full fat group.

The reduced fat Pringles contained a fat substitute called Olestra, which is not currently available in the UK.

"These substitutes are meant to mimic the taste of fat in foods that are normally high in fat while providing a lower number of calories, but they may end up confusing the body," said Susan E. Swithers, professor of psychological sciences. "We didn't study this in people, but we found that when rats consumed a fat substitute, learned signals that could help control food intake were disrupted, and the rats gained weight as a result.

"Substituting a part of the diet with a similar tasting item that has fewer or zero calories sounds like a common-sense approach to lose weight, but there are other physiological functions at work. Tastes normally alert the body to expect calories, and when those calories aren't present we believe the systems become ineffective and one of the body's mechanisms to control food intake can become ineffective."

In past studies, Swithers and Davidson found that when rats consumed artificial sweeteners, they were more likely to overeat. They believe that a similar disruption of taste-calorie relations may be happening with both artificial sweeteners and fat substitutes.

"When the mouth tastes something sweet or fatty it tells the body to prepare for calories, and this information is key to the digestive process," Swithers said. "This is a reminder to not discount the roles that taste and experience with food play in the way the body's systems work together."

In the light of this research it seems that dieters may be wise to stick to a diet that is naturally low in fats and sugars rather than resorting to fat and sugar substitutes.