Western Diets Turn on Fat Genes

How Energy-Dense Foods May Activate Genes That Ultimately Make People Obese

Those extra helpings of gravy and dessert at the holiday table are
even more of a problem to your waistline than previously thought.
According to a new research report recently appearing online in
The FASEB Journal, a diet that is high in fat and in sugar actually
switches on genes that ultimately cause our bodies to store too
much fat.

These foods strike you with a double-whammy as the task of converting
high-fat and high-sugar foods to energy is made even more difficult because
these foods also turn our bodies into fat-storage containers.

In the research report, scientists show that foods high in fat and sugar stimulate
a known opioid receptor, called the kappa opioid receptor (KOR), which plays
a role in fat metabolism. When this receptor is stimulated, it causes our bodies
to hang on to much more fat than they'd do otherwise.

According to the researchers involved in the study, "the data presented here
support the hypothesis that overactivation of the kappa opioid receptors
contribute to the development of obesity, especially during prolonged consumption
of high-fat, calorically dense diets."

To make this discovery, the research team conducted tests in two groups
of laboratory subjects. One group had the kappa opioid receptor genetically
deactivated and the other group was normal. Both groups were given a high fat,
high sucrose, energy dense diet for 16 weeks. While the control group gained
significant weight and fat mass on this diet, those with the deactivated receptor
remained lean. In addition to having reduced fat stores, those with the deactivated
receptor also showed a reduced ability to store incoming nutrients.

Although more work is required, this research may help address the growing
obesity problem worldwide in both the short-term and long-term. Most importantly,
this research provides more proof that high-fat and high-sugar diets should be
avoided. In the long-term, however, this research is even more significant, as
it provides a specific target for developing therapies for preventing obesity and
helping obese people slim down.

"In times when food was scarce and starvation an ever-present threat, an
adaptation that allows our bodies to store as much energy as possible during
plentiful times was probably a lifesaver. Conversely, by removing that opioid
receptor, we may have found a way to keep us from eating ourselves to death."
concluded the researchers.

FASEB (The Federation of American Societies for Experimental Biology)
publishes online, Stanford University Library.