Any smoker who has woken up on the couch clinging to a crusty fork and a mixing bowl that once contained a Paul Bunyan-sized portion of macaroni-and-cheese knows that marijuana makes you hungry. Led by Dr. Daniele Piomelli, UC Irvine researchers have discovered that fatty foods like macaroni-and-cheese, onion rings, and pizza with extra pepperoni make you hungry too. They actually trigger "marijuana-like chemicals" in the body called endocannabinoids. According to the study's results (released appropriately on July 4th, generally a day of heavy eating) this pleasurable biological reaction encourages diners to be gluttonous when they really ought to know better.
Working with rats (ever a charming stand-in for humanity), Piomelli and his crew saw that when the rats tasted fat, cells in their upper gut began generating endocannabinoids, an effect sugars and proteins notably did not have:
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 signaling 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 take-away is that scientists have a better idea of how an unhealthy diet contributes to weight gain and disease. Hopefully future studies will endeavor to explain the connection between fatty foods and very early morning screenings of The Holy Mountain, impromptu jam sessions, and nervous, solitary walks in the park.