Fire up a joint, rip a few bong hits, or take a toke from a pipe or vaporizer. There is one consequence of these actions that cannabis users can count on.
What it is that sends our taste buds into overdrive?
A new study from the journal Nature Neuroscience claims that it is a heightened sense of smell that makes a person crave food after using cannabis.
Science has known for decades that the human body has an endocannabinoid system. Endocannabinoids are compounds that have the same effect in the body as the cannabinoids in cannabis, like THC and CBD, but the body produces them naturally.
When a person uses cannabis, the cannabinoids from the plant (called phytocannabinoids) bind with receptors all over the body to produce different effects. But why is hunger one of those effects?
Perhaps it's because hunger enhances a person’s sensory perception. In ancient times, this sharpened us up so we could better hunt and gather food. It's called survival.
According to the study conducted by European scientists led by Giovanni Marsicano of the University of Bordeaux, when cannabinoids are received by cannabinoid type-1 (CB1) receptors in the main olfactory bulb (MOB) of the brain, they signal that the body is starving.
Mice were used as test subjects. Since all mammals share cannabinoid similarities, the brains of mice and humans function quite alike.
“CB1 receptors promote food intake in fasted mice by increasing odor detection,” according to the researchers. This increase in smell power, which occurs naturally when someone is actually hungry, leads to the brain thinking that the body is not just hungry, but that it is actually starving.
As a result, the brain craves fatty foods so that the body can store calories for later. That would explain why junk food is so appealing when we're buzzed.
How about this for a puzzle: Other studies show that cannabis users are, as a group, significantly slimmer than non-users. But that's another story.
While cannabis researchers welcomed this recent study, it is only part of the picture. Researchers have been gleaning bits and pieces over the years. Separate studies show different results, they but don’t contradict.
In 2011, a study led by a University of California-Irvine professor of pharmacology named Danielle Piomelli showed that when the taste of fatty food hits a person’s system, it sends signals to the gut to produce endocannabinoids. CB1 receptors in the gut receive these endocannabinoids, which increases the desire for fatty foods.
In this study, published in the Proceedings of the National Academy of Sciences, researchers went a step further by genetically engineering mice that do not have CB1 receptors.
The result was that the “knock-out” mice still wanted to eat, but the craving for fatty foods was gone. This led researchers to believe that blocking the CB1 receptors in humans would cause the same effect and help to fight obesity. Unfortunately, they were unable to find a safe drug to block those receptors, and since so much is still unknown in this area of biology, that may have been for the best.
In another study, conducted by European researchers supported by the UK Medical Research Council and published in The Journal of Biological Chemistry, the result suggested that “Endocannabinoids and ghrelin [a natural hormone] are potent appetite stimulators and are known to interact” with the hypothalamus. Scientists found by injecting 2-AG (the endocannabinoid produced in the body that most resembles THC) into subjects that stimulation occurs in the hypothalamus the same as if the 2-AG were created by the body naturally.
The academic journal Neuropharmacology published a study in July of 2012 that had yet another take on munchies. While the researchers admitted that “[c]annabinoid receptor agonists are known to stimulate feeding and animals,” they believe that instead of being caused by heightened senses, it is actually the instant reward response of dopamine that is generated in the body after eating “highly palatable food.” In turn, that increase in pleasure makes you want to keep eating more of it.
All of these studies provide plausible and scientifically viable reasons why cannabis stimulates appetite. Perhaps each provides some truth.
The bottom line is that the cannabinoids in the plant, especially THC, interact with receptors in our bodies, programming us to want more of not just any food, but fatty food.
So if you’re on a diet, hide those cookies before you spark up that joint.