Why does cannabis make us hungry?

One of marijuana’s most common side effects, explained

We’ve all experienced it, that insatiable hunger that often follows cannabis use. The unsuppressable urge for “just a little bit more” that inevitably leads to “just a little bit more, again” and so on until the whole bag/tray/trough is empty. This phenomenon is popularly known as “the munchies,” and while that sounds silly, rest assured, it’s very much a real thing.

It’s long been noted as a side-effect, but our scientific understanding of the munchies is only a few years old. In 2014, a study published in Nature revealed where those false/amplified hunger signals were coming from, and why food smelled and tasted so damn good after using cannabis.

According to the study’s authors at Yale, the stomach’s urgency to eat everything in sight is actually a trick being played by the brain. Turns out THC fits perfectly into and activates the CB1 receptor in the brain’s olfactory lobe (HQ for the sense of smell) that in turn enhances smells and tastes and makes you want more and more.

“By observing how the appetite centre of the brain responds to marijuana, we were able to see what drives the hunger brought about by cannabis and how that same mechanism that normally turns off feeding becomes a driver of eating. It’s like pressing a car’s brakes and accelerating instead,” the study’s lead author, Tamas Horvath said in a press release.

The brain produces its own natural endocannabinoids when the body is actually hungry, and these normally set off the CB1 receptor, which then leads you into the kitchen to cook up a meal (or at the very least, open a bag of chips). But cannabis activates the exact same receptor, regardless of how much you just ate.

So that explains the desire to eat something, but why can’t we ever seem to get enough?

Well, the same smart group of researchers at Yale asked just that question and went digging some more. They discovered that, not only was the CB1R receptor being activated, but a whole other set of cells, the pro-opiomelanocortin (POMC), that normally trigger fullness, were being reversed and calling out for whatever leftovers happened to be nearby instead of saying “Okay, we’ve had enough lasagna for tonight.”  

“We were surprised to find that the neurons we thought were responsible for shutting down eating were suddenly being activated and promoting hunger, even when you are full,” said Horvath. “It fools the brain’s central feeding system.”

Sneaky devils!

So the next time the munchies strike, first know that it’s not your belly doing the talking, it’s your brain—and it’s lying to you! And second, maybe keep a slew of healthier snacks on hand (2017 is the year you learn to love baby carrots), instead of inhaling a family-sized bag of chocolate-covered pretzels. Great, now we want chocolate-covered pretzels...

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