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Everyone from the heaviest pothead to the most ardent teetotaler knows that smoking weed can give you the munchies, but up until recently, scientific research confirming or denying this anecdotal experience has been slim. The federal prohibition on cannabis has made it extremely difficult for researchers to dig into the method by which marijuana might cause this phenomenon, but as more U.S. states and even entire countries relax their laws on reefer, scientists are finally getting closer to understanding the relationship behind pot and hunger.

At a recent meeting of the Society for the Study of Ingestive Behavior, doctors revealed that they’ve made some headway on this topic. Researchers at the Department of Integrative Physiology and Neurosciences at Washington State University have been dosing rats with cannabis vapor and examining the effects upon their eating behavior. The team conducted a series of studies in which the rats' meals were closely monitored under the effects of precisely measured doses of cannabis.

“We all know cannabis use affects appetite, but until recently we’ve actually understood very little about how or why,” Jon Davis, Ph.D., lead researcher in these new studies, said in a statement. “By studying exposure to cannabis plant matter, the most widely consumed form, we’re finding genetic and physiological events in the body that allow cannabis to turn eating behavior on or off.”

“We found that cannabis exposure caused more frequent, small meals,” Davis said. “But there’s a delay before it takes effect.” This delay led Davis and his team to test a hypothesis concerning ghrelin, a hormone released by the stomach when an animal is hungry. The researchers discovered that cannabis doses triggered a surge of ghrelin, and also altered ghrelin receptors located in the hypothalamus to be more responsive to the hunger hormone.

Scientists have already identified the hypothalamus — an ancient part of the brain that links the endocrine system to the nervous system — as a center of cannabis activity. The hypothalamus contains many CB1 receptors which respond to cannabinoids, including THC. These receptors are also found in the olfactory bulb, and stimulation from cannabis can increase one's sense of smell, which can in turn make food more appealing. Similarly, these receptors are also found within the stomach, which can regulate one’s feelings of hunger, as Davis’ research supports.

Davis is hopeful that his team’s finding can lead to the creation of new medicines to treat anorexia brought on by other illnesses. Several serious ailments like cancer, HIV, heart disease, and metabolic disorders can all cause severe appetite loss, and cannabis treatments that could boost a patient's natural hunger hormones without adverse side effects would be in high demand.

While much of the research on cannabis and food has focused on the hunger-boosting powers of THC, researchers have identified another cannabinoid that can actually diminish hunger. Tetrahydrocannabivarin, or THCV, has been found to reduce one’s appetite, in addition to improving insulin resistance and preventing seizures. GW Pharmaceuticals, whose anti-seizure drug Epidiolex just became the first cannabis-derived drug to be approved by the FDA, is currently researching a THCV-based medication that could help treat eating disorders, Type II diabetes, or other diet-related issues by means of appetite suppression.