Fatty Foods Make Us Hungry—And Fat

| Fri Jun. 5, 2009 4:10 PM EDT

Here's a clue to the virulence of the obesity epidemic. New research suggests the hunger hormone ghrelin is activated by fats from the foods we eat, not those made in the body.

This natural process was designed to optimize metabolism and promote the storage of body fat. And this was useful when food was hard to come by and we had to work physically hard to get it.

Now it backfires on us in the form of fat.

Ghrelin—the hunger hormone—is believed to accumulate during periods of fasting and is found in the body in high concentrations just before meals. It's activated by a fatty acid added by an enzyme called GOAT. Originally it was assumed that the fatty acids attached to ghrelin by GOAT were produced by the body during fasting.

But the new data published in Nature Medicine suggest the fatty acids needed for ghrelin activation come directly from ingested dietary fats.

Exposed to fatty foods, mice with more GOAT gain more fat. Mice without GOAT gain less fat since their brain never receives the signal to store the fat.

Why am I worried that this will lead to a pharmaceutical fix that will allow us to continue overeating without getting fat?