Drinking diet pop and consuming low-calorie-sweeteners in a bid to lose weight? A new study may have you ripping open those sugar packets.

Psychologists at Purdue University have discovered in rat experiments that heavy use of no-calorie sweeteners can actually make it harder to shed extra pounds. The thinking is that the sweeteners make it more difficult to control food intake and body weight.

Authors theorize the use of low-calorie sweeteners in products like diet pop has contributed to the North American epidemic of obesity.
(CBC)

When researchers fed rats a yogurt that had been sweetened with glucose (a simple sugar), and another group of rats the same amount of yogurt sweetened with zero-calorie saccharin, the saccharin-eating rats ate a greater number of calories, gained more weight, put on more body fat and didn't make caloric allowances for the extra calories they consumed.

They also found that in rats that ate saccharin, their core body temperatures rose less than in rats that ate sugar, prior to eating. Core body temperature normally rises when an animal or person prepares to eat, so the researchers believe this observation shows that saccharin-eating rats' response to food has been blunted, leading to a lower metabolic burn and more weight accumulation.

The researchers theorize the saccharin led the animals to associate the taste of sweet with a low-calorie meal, encouraging them to consume more. Normally, eating a food sweetened with sugar is associated with a high number of calories, promoting satiety.

The authors theorize that the use of low-calorie sweeteners in many products has contributed to the North American epidemic of obesity.

"The data clearly indicate that consuming a food sweetened with no-calorie saccharin can lead to greater body-weight gain and adiposity than would consuming the same food sweetened with a higher-calorie sugar," the authors wrote.

They also believe that artificial sweeteners like aspartame, sucralose and acesulfame K may have similar effects to saccharin's.

The study is published in the February issue of Behavioural Neuroscience.