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The reason you crave high-calorie foods after using cannabis is clearer thanks to recent research. Lucas Ottone/Stocksy
  • A new study suggests that not only do people experience the munchies after consuming cannabis, but worms do too.
  • The point of the study was to research the cannabinoid receptor, which is present even in basic living creatures like worms.
  • A better understanding of the endocannabinoid system and its links to appetite may help treat obesity, anorexia, and other conditions in the future.
  • Researchers say the findings from the study could have important implications for future pharmaceutical development as well.

You’ve likely heard of the munchies. Perhaps you’ve even experienced them. The term is frequently used to describe the cravings for highly-caloric and sometimes very sweet foods after using cannabis, which contains tetrahydrocannabinol (THC).

It’s still unclear precisely why the munchies occur. But worms appear to get them, too, according to a new study published on April 20 in Current Biology.

The researchers were looking at the food preferences of a well-studied worm known as the nematode worm (C. elegans). They reported that they react to cannabinoids in the same way as humans — by opting for delicious, high-calorie foods.

“This is actually fascinating,” says Dr. Sherry Yafai, a board-certified emergency medicine physician at Saint John’s Physician Partners Urgent Care, adjunct assistant professor at Saint John’s Cancer Institute, and cannabis specialist. “The presence of the cannabinoid receptor, which in medicine and science is so often ignored, is present in the most basic living creature, a worm.”

The receptor is present in the worm and humans, Yafai notes, begging the question: Why is this receptor so important that it has persisted throughout species and generations?

According to the study’s senior author, Shawn Lockery, PhD, a neuroscientist and a professor at the University of Oregon, the researchers happened on the experiment almost by accident.

And headlines about worms getting the munchies may seem like a 4/20 gimmick. But the results of this study could have important implications in the medical world.

“Understanding the incredibly complex endocannabinoid system may unlock answers to scientific questions that have been eluding us in medicine,” Yafai says. “In this study, researching an idea as simple as appetite can help us treat obesity and anorexia induced by cancer/chemotherapy and other chronic illness.”

Lockery and Yafai went beyond the buzzy headlines and discussed the research, what we know about the munchies, and the potential long-term implications of the study.

There’s a difference between being ravenous and the munchies.

“The munchies is a specific increase in appetite for very high-calorie foods,” Lockery says.

And it happens after consuming marijuana.

“How does that happen? The short answer is that we don’t know, but we know pieces,” Lockery says.

For starters, Lockery believes it’s likely an evolutionary event.

“We should think of it as probably a last-ditch emergency when an animal is starving,” Lockery says. “An animal who is truly in danger of dying from a lack of calories should not waste their time with oatmeal. They should go after the fat, sugar — things with tons of calories. It’s an emergency, bring-back-to-life thing.”

We have cannabinoid receptors throughout the body, including our tastebuds.

“Under the influence of THC, sweet things taste sweeter,” Lockery says. “That can be one reason why people increase their appetite for sweet things — others like fattier. There’s evidence cannabinoids affect not only taste but smell. But there is probably deeper stuff going on…the nervous system that changes what you crave.”

Lockery says scientists are looking into precisely what’s happening in experiments with rodents. In the meantime, what if you aren’t an animal in desperate need of high-calorie food to survive?

“Clinically speaking, munchies tend to be related to dose and can be limited by decreasing the dose of THC,’ Yafai says. “Simply stated, use less inhalations or a lower-percentage THC option in the flower you choose. Another option is adding CBD into the mix, which tends to blunt some of the munchie effects of THC.”

As a systems neuroscientist, Lockery has taken a keen interest in studying how the brain controls behavior and how small networks of neurons cooperate to benefit an animal.

The nematode has 302 neurons compared to 86 billion in the human brain. But at a molecular level, Lockery says that the cannabinoid system in humans and worms are similar.

Cannabinoids aren’t just in marijuana or oils. Humans have an endocannabinoid system, and Lockery says it plays roles in eating, anxiety, learning, memory, and reproduction.

Within the human body, cannabinoids act as neurotransmitters. They bind to cannabinoid receptors (or detector proteins) in the nervous system and other body parts, including the brain.

“When [the receptors] detect a cannabinoid, they cause biochemistry to happen inside the cell, and that’s the signaling process,” Lockery says. “Ultimately, that kind of signaling, through a number of chain reactions not fully understood, causes people’s specific preference for highly caloric foods.”

Lockery knew nematodes had an endocannabinoid system. However, he and his team didn’t know if worms got the munchies. He said the idea came to them during a neuroscience version of “playtime” or “Friday happy hour.”

The team was winding down and decided to see if dousing worms in THC would change their food preferences. It was shortly after Oregon legalized recreational sales of marijuana, and the researchers had spent years investigating how animals made economic decisions around food by challenging them with various options from expensive and high-quality to tolerable and cheap.

“It’s a big, unopened question how subjective decisions are translated in the brain and represented in action,” Lockery says. “Not all bacteria are created equal in terms of how fast an individual worm will grow on a bacteria. Although they are born naive to food, they develop preferences early in life.”

This behavior is similar to humans. But would worms exhibit a similar response to food when soaked in THC? The answer, according to the researchers, is yes. The worms ate more, especially their favorite foods, post-THC soak. In another study, researchers genetically replaced the worm’s cannabinoid receptor with a human’s. The worms still got the munchies.

“The main thing that it tells us is that it reinforces the idea that endocannabinoid signaling is universal in animals, and it’s been that way for at least 500 million years,” Lockery says. “The line leading to humans and nematodes diverted 500 million years ago. It’s long in evolutionary time, but these genetic, biological parts have not changed…it reinforces that we are not so different than a tiny little roundworm.”

In 2006, The European Medicines Agency approved Rimonabant, an anti-obesity medication that suppressed appetite by targeting the endocannabinoid. The drug was never approved by the FDA and pulled in 2008 because of psychiatric side effects, including suicide risk.

“It’s widely believed that endocannabinoid signaling has therapeutic potential because it is in almost every tissue in our body,” Lockery says. “The problem with targeting the endocannabinoid system for health purposes is that it is in every tissue in our body. That means if you design a drug that targets the receptor proteins for endocannabinoid, you are affecting the signaling process everywhere in your body.”

Lockery says that in the wake of Rimonabant, people designing drugs targeting the endocannabinoid system know to take a different approach.

“They are going to have to find ancillary proteins that might be different from tissue to tissue, that would give you tissue-specificity,” Lockery says.

Lockery is pursuing further research into that, which Yafai looks forward to learning more about because it could improve the health and quality of life of individuals using marijuana for medical treatment.

Obesity is linked to heart disease, hypertension, diabetes, and countless other illnesses,” Yafai says. “The flip side of the same coin is anorexia from cancer, chemotherapy, chronic illness, and GI disorders is also a considerable problem for patients…Working on improving both sides of this coin of appetite — suppression and excess — is an important aspect of our scientific research.”