The Lay's potato chip slogan "betcha can't eat just one" may not actually be so far from the truth. Researchers at UC Irvine found that fats in starchy foods such as french fries and potato chips trigger the body to produce natural marijuana-like chemicals called endocannabinoids. Endocannabinoids make these foods irresistible and stimulate a biological mechanism that encourages gluttonous behavior.
In the study, published in the online edition of Proceedings of the National Academy of Sciences, found that when rats tasted something fatty, their upper gut cells produced endocannabinoids. This did not happen when the rats ate sugar or protein. The results suggested that it may be possible to curb overeating fatty foods by obstructing endocannabinoid activity (such as using a drug that "clogs" the receptors).
The process starts on the tongue, where the fats send a signal to the brain, and then through a nerve bundle to the intestines. This signal then triggers the production of endocannabinoids, which then makes you keep chowing down.
So, next time you gorge yourself on one too many helpings of nachos, just blame your endocannabinoids. It's not you, it's them.