Scientists Solve Marijuana Munchies Mystery

by Liz Neporent
January 17, 2024 at 4:07 PM UTC

Researchers exposed rodents to cannabis vapor and found it significantly increased their appetite by activating specific brain neurons.

Clinical Relevance: Now we know why pot smokers get the munchies

  • A new study found that cannabis activated brain neurons, specifically in the mediobasal hypothalamus, leading to increased hunger and more frequent eating in mice.
  • Despite eating more often, the mice didn’t change their overall activity levels or physical exercise habits.
  • This research has implications for medical cannabis use, particularly for those needing appetite stimulation.

Ever wondered why a puff of cannabis often leads to a raid on the fridge? Scientists have finally cracked the case.

In a recent Scientific Reports study, researchers examined the brain’s reaction to Cannabis Sativa, the plant responsible for giving pot smokers the munchies after firing up a joint. 

While food cravings linked to cannabis  might seem like a trivial thing, they’ve stumped scientists for years. The answer, it seems, is buried deep within the brain, in a spot called the mediobasal hypothalamus, the de facto cerebral food-craving command center. 

High Mice Eat More

In the study, the researchers explored how cannabis influences hunger by observing its effects on rodents. They first exposed the creatures to cannabis vapor and then monitored their eating habits to see how the smoke affected appetite and food intake.

The scientists didn’t note an exact amount of increase in food consumption by the mice. Nor did they specify if the mice preferred sweet, salty, or crunchy foods. But they did find that the mice ate quite a bit more after the exposure to the cannabis smoke. Basically, it was the rodent equivalent of pigging out. 

To understand the brain’s role in these changes, they used special imaging and electrical recording techniques which allowed them to see what happened in the brain once the animals inhaled cannabis vapor. They discovered that specific neurons in the mediobasal hypothalamus lit up. The neurons seemed to act like little appetite switches – when turned on, they led to hunger, even if the animal had already eaten.

This increase in neuronal activity was observed during both the anticipation of food and the actual consumption, suggesting that cannabis stimulates a broad range of appetite-related brain activities.

“When the mice are given cannabis, neurons come on that typically are not active,” said Jon Davis, an assistant professor of neuroscience at WSU and one of the paper’s authors. “There is something important happening in the hypothalamus after vapor cannabis.”

Stable Activity Levels

Interestingly, it wasn’t only about eating more. The mice in the study started cutting back to smaller meals but dining more frequently. They were willing to work harder to gain access to tasty snacks. However, in a plot twist, it didn’t make them shun their exercise wheels. Their overall activity levels remained the same, they just became snackier.

Besides solving a long standing stoner mystery, this research has some serious takeaways. It could help medical cannabis users of the human variety  especially those who need a boost in appetite due to medical conditions. Understanding how cannabis affects the urge to eat could lead to better treatments and more effective use of medical marijuana.

As Davis puts it, “We now know one of the ways that the brain responds to recreational-type cannabis to promote appetite.

So, mystery solved.

The next time you find yourself reaching for that bag of chips after a toke, remember it’s your brain’s mediobasal hypothalamus flipping the hunger control switch. And, as both recreational and medical marijuana become legal in more places, scientists may uncover more about the way the drug affects the brain. Stay tuned, and maybe keep some snacks handy.

Further Reading:

Cannabis and Neuropsychiatry

What Physicians Need to Know About Medical Marijuana

Leukoencephalopathy After Excessive Cannabinoid Use

A Randomized, Double-Blind, Placebo-Controlled Pilot Trial of the Acute Antisuicidal and Antidepressant Effects of Intranasal (R,S)-Ketamine in Severe Unipolar and Bipolar Depression With and Without Comorbid Alcohol Use Disorder

Intranasal ketamine induced rapid antidepressant effects versus placebo but did not significantly change suicidal ideation scores in patients with alcohol use disorder and suicidal ideation with past attempt.

Gregory H. Jones and others

Case Report

Inhalant Screening in Early Adolescence: Missed Opportunity to Prevent Escalation to Polysubstance Use and Related Consequences

The authors present a case of polysubstance use in an adolescent for whom undetected inhalant use played a key role in escalation of substance use and psychiatric comorbidities.

Jennifer Yokoyama and others