New research found that cannabis stimulates appetite in both rats and humans, suggesting the munchies are driven by shared biological mechanisms rather than culture or expectation. The findings could help scientists better understand appetite regulation and explore future treatments for conditions involving nausea, weight loss, or reduced food intake, while highlighting the need for further clinical research.
Almost anyone familiar with weed knows that urgent, absurd, and sometimes unstoppable need to eat something after getting high: the munchies. But, apparently, it isn’t an exclusively human experience, nor a cultural myth. Rats seem to get the munchies too, and that could tell us quite a lot about appetite, the endocannabinoid system, and potential medical applications of cannabis.
A joint study by the University of Calgary and Washington State University analyzed how cannabis impacts appetite in both rats and humans. The research, published in Proceedings of the National Academy of Sciences, sought to better understand what happens in the body and brain when THC triggers that overwhelming urge to eat.
The Munchies Were Not Just a Human Thing
The Canadian portion of the work was led by neuroscientist Matthew Hill and researcher Catherine Hume, from the University of Calgary. There, the team exposed rats to cannabis vapor and observed that, during the first hour, the animals ate significantly more. In other words, their appetite was stimulated—and substantially so.
For years, the “munchies” have been treated as an anecdote of cannabis culture, or even as a possible placebo response. But seeing similar behavior in rats changes the conversation: if other mammals respond in a similar way, the phenomenon cannot simply be explained by habit, suggestion, or social context. Something physiological is clearly going on.
The methodology also matters. As Hill explained, many previous animal studies used injectable cannabinoids, such as THC. The problem is that this route does not closely resemble the way many people use weed. In this case, researchers used cannabis vapor, an approach closer to inhaled human use.
In parallel, the Washington State University team carried out a human phase. It included 82 people between the ages of 21 and 62, who inhaled vaporized delta-9 THC-dominant cannabis or a placebo. When comparing both species, researchers observed that cannabis rapidly and strongly stimulated appetite in both humans and rats.
Rats Eat Even When They Are Full
One of the most striking findings was that rats ate even when they were already satisfied. The animals that weren’t exposed to cannabis showed practically no interest in food if they were full. In contrast, intoxicated rats went back for more food as if they were hungry again.
The study also tested a very common idea: that marijuana sends us straight to junk food. But the results were more complex. Researchers expected rats to show a clear preference for certain foods, especially carbohydrates. However, when they were offered different options, the animals seemed inclined to eat just about anything, without a marked predilection toward fats, proteins, or carbohydrates.
Something similar happened in humans. Cannabis did not appear to significantly change macronutrient preference. In other words, participants did not necessarily gravitate toward one specific type of food: what increased was the general drive to eat. Rather than craving one particular category, the effect seemed to be greater overall motivation to eat.
CBC highlighted one surprisingly relatable detail: according to the lead researcher, in the human part of the study, where participants had access to a cafeteria-style food selection, one of the most chosen options was beef jerky.
Another interesting nuance is that the increase in appetite was acute, not necessarily sustained throughout the entire day. According to UCalgary, although cannabis can generate a sudden wave of hunger, that does not mean users end up consuming more total calories than non-users over the course of a full day. In other words: the munchies can be intense and immediate, but they do not necessarily translate into eating more throughout the day.
What it Could Mean for Medicine
Beyond the curiosity—or the potential memes—, the study presents medical implications, particularly around how cannabis stimulates appetite or how it may help inform new strategies for people struggling with gaining weight, lack of appetite, or nausea associated with treatments such as chemotherapy.
Hill noted that one of the most recognized medical uses of cannabis appears precisely in the context of chemotherapy-induced nausea. That discomfort can generate what is known as taste aversion: the brain associates certain foods with nausea and then rejects them. In that context, cannabinoids could play a dual role: reducing nausea first, then helping restore appetite.
The study also raises questions about eating disorders such as anorexia, though researchers are careful not to overstate the findings. Hill suggested that, in very specific forms, cannabinoids could help reduce some of the anxiety associated with food and increase food reward. But he also clarified that this line of inquiry remains highly speculative.
That warning is key. Grace Beda, a registered dietitian consulted by CBC, noted that the clinical evidence on cannabis and weight gain remains mixed. The fact that cannabis can stimulate appetite in certain contexts does not automatically mean it is the best medical option for all patients, nor that it guarantees significant weight gain.
There is also a practical tension: although inhaled THC may be more effective at stimulating appetite than oils, drops, or edibles, smoking or vaping is not usually recommended for oncology patients during treatment due to potential risks to the lungs. For that reason, non-inhaled routes are often suggested, although their effectiveness may vary.
The contribution of this research, then, is not simply confirming that the munchies exist. Cannabis culture has known that for decades. What matters is that the study shows a measurable response, shared across species and linked to biological circuits that regulate appetite, reward, and food-seeking behavior.
Ultimately, rats get the munchies too. But the most important point is what that behavior can reveal about the brain, hunger, and the therapeutic potential of cannabinoids. The question that remains open is how to translate that knowledge into safe, precise, and truly useful treatments for those who need to regain their appetite, without resorting to easy promises or one-size-fits-all solutions.
