Why we cant resist chips
Researchers at the University of California – Irvine (ICI) found that fats in these foods trigger a surprising biological mechanism that produces natural marijuana-like chemicals in the body called endocannabinoids, which increases the craving for more fatty food.
In their study, appeared online in the Proceedings of the National Academy of Sciences, the researchers discovered that when rats tasted something fatty, cells in their upper gut started producing endocannabinoids. Sugars and proteins, the researchers noted, did not have this effect.
The process starts on the tongue, where fats in food generate a signal that travels first to the brain and then through a nerve bundle called the vagus to the intestines.
There, the signal stimulates the production of endocannabinoids, which initiates a surge in cell signalling that prompts the wanton intake of fatty foods, probably by initiating the release of digestive chemicals linked to hunger and satiety that compel us to eat more, the researchers said.
The findings suggest it might be possible to curb this tendency by obstructing endocannabinoid activity, for example, by using drugs that "clog" cannabinoid receptors, said Daniele Piomelli, who led the ICI study.
"Since these drugs wouldn`t need to enter the brain, they shouldn`t cause the central side effects — anxiety and depression — seen when endocannabinoid signalling is blocked in the brain," he noted.
Piomelli said that from an evolutionary standpoint, there`s a compelling need for animals to consume fats, which are scarce in nature but crucial for proper cell functioning.
In contemporary human society, however, fats are readily available, and the innate drive to eat fatty foods leads to obesity, diabetes and cancer.
"This is the first demonstration that endocannabinoid signalling in the gut plays an important role in regulating fat intake," Louise Turner Arnold Chair in the Neurosciences and professor of pharmacology added.