Battling with weight gain? This research suggests you avoid anything made with a synthetic fat or artificial sugar substitute.

New research undertaken at Purdue University in the US has indicated that synthetic fat substitutes used in low-calorie potato chips and other foods could backfire and contribute to weight gain and obesity.

The finding follows earlier research by the same university that showed saccharin and other artificial sweeteners also can also promote weight gain and increase body fat.

Researchers noted that the use of artificial sweeteners and fat substitutes has increased dramatically over the past 30 years, mirroring the worldwide increase in obesity.

It now seems that dieters who have turned to these artificial means to lower calories while still eating foods that taste sweet or fatty may have inadvertently been contributing to their own weight gain rather than decreasing it.

This finding may be of importance to working carers, not only in terms of managing their own health and weight, but also in managing the weight and health of those for whom they care.

If you are eating foods made with calorie-free synthetic fat, or those sweetened with artificial sweeteners, you could be doing yourself and those you love a great disservice.

The synthetic fat substitute study challenges the conventional wisdom that foods made with fat substitutes help with weight loss.

“Our research showed that fat substitutes can interfere with the body’s ability to regulate food intake, which can lead to inefficient use of calories and weight gain,” said Susan E. Swithers, PhD, the lead researcher and a Purdue psychology professor. The study was published online in the APA journal Behavioural Neuroscience.

The study used laboratory rats that were fed either a high-fat or low-fat diet of chow. Half of the rats in each group also were fed regular Pringles potato chips which are high in fat and calories.

The other half of the rats in each group were also fed Pringles, but on some days they had the regular variety and on other days they had Pringles ‘Light’ chips. The Pringles ‘Light’ chips are made with olestra, a synthetic fat substitute that has zero calories and passes through the body undigested.

For rats on the high-fat diet, the group that ate both regular Pringles and ‘Light’ Pringles consumed more food, gained more weight and developed more fatty tissue than the rats that ate only the regular high-calorie chips. Disturbingly, the fat rats also didn’t lose the extra weight even after the potato chips were removed from their diet.

Why would a fat substitute confuse the body? The researchers postulate that food with a sweet or fatty taste usually indicates a large number of calories, and the taste triggers various responses by the body, including salivation, hormonal secretions and metabolic reactions. Fat substitutes can interfere with that relationship when the body expects to receive a large burst of calories but is fooled by a fat substitute.

There is some good news if a diet is naturally low in fat. The rats that were fed a low-fat diet didn’t experience significant weight gain from either type of potato chips.

Of concern is that when those same rats were switched to a high-fat diet, the rats that had eaten both types of potato chips ate more food and gained more weight and body fat than the rats that had eaten only the high-calorie chips.

Swithers and Davidson have reported similar findings in previous rat studies that showed saccharin and other artificial sweeteners also can promote weight gain and increased body fat.

Their research at Purdue University’s Ingestive Behaviour Research Centre found that relative to rats that ate yogurt sweetened with glucose (a simple sugar with 15 calories/teaspoon, the same as table sugar), rats given yogurt sweetened with zero-calorie saccharin later consumed more calories, gained more weight, put on more body fat, and didn't make up for it by cutting back later, all at levels of statistical significance.

The researchers surmised that by breaking the connection between a sweet sensation and high-calorie food, the use of saccharin changes the body's ability to regulate intake. Problems with self-regulation might explain in part why obesity has risen in parallel with the use of artificial sweeteners.