Washington, Dec 1 (ANI): Here's a proof why a diet high in fat and in sugar should be avoided: a new research has shown that Western diets actually switch on genes that ultimately make us obese.

This means that these foods hit us with a double-whammy as the already difficult task of converting high-fat and high-sugar foods to energy is made even harder because these foods also turn our bodies into "supersized fat-storing" machines.

In the new study, scientists showed that foods high in fat and sugar stimulate a known opioid receptor, called the kappa opioid receptor, which plays a role in fat metabolism.

When this receptor is stimulated, it causes our bodies to hold on to far more fat than our bodies would do otherwise.

Study author Traci Ann Czyzyk-Morgan said that "the data presented here support the hypothesis that overactivation of kappa opioid receptors contribute to the development of obesity specifically during prolonged consumption of high-fat, calorically dense diets."

To make this discovery, Czyzyk-Morgan and her colleagues conducted tests in two groups of mice.

One group had the kappa opioid receptor genetically deactivated ("knocked out") and the other group was normal. Both groups were given a high fat, high sucrose, and energy dense diet for 16 weeks.

While the control group of mice gained significant weight and fat mass on this diet, the mice with the deactivated receptor remained lean.

In addition to having reduced fat stores, the mice with the deactivated receptor also showed a reduced ability to store incoming nutrients.

Although more work is necessary to examine what the exact effects would be in humans, this study may help address the growing obesity problem worldwide in both the short-term and long-term.

The study appears online in The FASEB Journal. (ANI)