The Munchies Are Real—and Your Brain Is To Blame
Vaporized cannabis increases food intake by activating brain reward pathways that override fullness signals.
Even a full stomach cannot stop the drive to eat when cannabis is involved.
A new study, conducted at Washington State University (WSU) and the University of Calgary, found that vaporized cannabis triggers a rapid increase in food intake by hijacking reward signals in the brain.
The findings show that “the munchies” are a brain-mediated response that overrides normal signals of being full.
The biological mystery of the munchies
Cannabis use is common globally, with ~4% of the population using it regularly. One of its most famous effects is the “munchies”; the sudden, intense hunger that follows use. While it is a common part of pop culture, there is a lack of detailed data on how it emerges in the brain.
Scientists recognize that the endocannabinoid system helps manage energy balance through CB1 receptors. Previous research shows that THC, the main psychoactive part of cannabis, triggers appetite. However, the specific reason for this has remained unknown. In prior work, it was hard to tell if the drug caused hunger or if it simply made eating more enjoyable.
Understanding these signals is important for medicine. Many people lose their appetite due to illness, which leads to dangerous weight loss. Scientists need to separate homeostatic hunger, which is the body's need for fuel, from hedonic motivation, which is eating for pleasure.
Past studies focused on hunger but did not always look at the effort a person or animal would make to get food. A research gap existed in connecting human behavior with the specific brain pathways involved.
The new study aimed to quantify how vaporized cannabis changed food intake and to see if these changes are driven by the brain's reward centers.
Cannabis vapor changes eating behavior
The researchers used a human trial with 82 volunteers between 21–62 years old. In this double-blind study, participants vaped 20 or 40 milligrams of cannabis or a placebo. They then had access to various snacks.
“The human study found that, irrespective of body mass index, time of last food consumption, sex, or how much cannabis was consumed, human participants who used cannabis during the trial ate significantly more food,” said senior author Dr. Ryan McLaughlin, an associate professor at WSU.
Most eating happened in the first 30 minutes, and participants showed a strong preference for savory, high-protein snacks.
“Beef jerky was one of the number one things intoxicated people gravitated toward, which I don’t understand. Honestly, I would have thought chocolate, chips, Rice Krispies treats—things like that,” said co-author Dr. Carrie Cuttler, an associate professor at WSU.
A higher dose of 40 milligrams did not lead to more eating than the 20-milligram dose, suggesting a limit to the drug's effect on appetite.
To test the drive for food, the team used a rat model. Rats were trained to press a lever to receive a food reward.
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Even when the rats were already full, those that inhaled cannabis vapor worked hard to get more food.
“The sober animals are kind of like, ‘I'm full. Why do I care?’ They don't put in any effort at all. They barely work in any capacity to get access to food. But you get them stoned again, and even though they're now full and they've eaten, they go right back as if they're starving,” said senior author Dr. Matthew Hill, a professor at the University of Calgary.
The type of food did not change the result. “The same thing we saw in the humans we saw in the rats. We kind of thought it would make them want to eat carb-rich foods, but that didn’t seem to be the case. It just seemed to be any food,” Hill added.
The researchers then blocked specific receptors to see where the effect started.
Blocking receptors in the brain stopped the overeating, but blocking them in the rest of the body did nothing.
“That’s what the natural endocannabinoid system does in the hypothalamus,” McLaughlin said. “But THC hijacks that entire system. So even though you’re not necessarily hungry, THC can stimulate cannabinoid receptors in the brain and make you feel hungry.”
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“That’s what really gives us the opportunity to look at whether this is something brain-mediated or gut-mediated, and this generally shows ‘the munchies’ are mediated by the brain,” McLaughlin explained.
Medical applications for cannabis induced hunger
Understanding how cannabis drives hunger can help people with wasting syndromes. Patients with HIV, AIDS, or those on chemotherapy often lose their appetite, which can be dangerous.
“There are a lot of different diseases, conditions, and disorders associated with wasting syndromes and lack of appetite, and this study really supports the idea that cannabis can be used medicinally to increase appetite in people,” said Cuttler.
By targeting brain-based motivation, doctors might find better ways to help patients maintain weight and strength.
Future research will be needed to identify the specific brain areas that are most involved. This could lead to treatments that boost appetite without making patients feel high.
“There’s very little documentation of the munchies phenomenon, but this paper really starts to tap into some of the mechanisms that might be responsible,” said Cuttler.
Reference: Hume C, Cuttler C, Baglot SL, Javorcikova L, McLaughlin RJ, Hill MN. Cannabis produces acute hyperphagia in humans and rodents via increased reward valuation for, and motivation to, acquire food. Proc Natl Acad Sci USA. 2025;122(52):e2518863122. doi: 10.1073/pnas.2518863122
This article is a rework of a press release issued by Washington State University. Material has been edited for length and content.
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