Mulling the marijuana munchies: How the brain flips the hunger switch

February 18, 2015

Science Daily/Yale University

The "munchies," or that uncontrollable urge to eat after using marijuana, appear to be driven by neurons in the brain that are normally involved in suppressing appetite, according to a new study by Yale School of Medicine researchers in the Feb. 18 issue of the journal Nature.

Lead author Tamas Horvath and his colleagues set out to monitor the brain circuitry that promotes eating by selectively manipulating the cellular pathway that mediates marijuana's action on the brain, using transgenic mice.

"By observing how the appetite center 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," said Horvath, the Jean and David W. Wallace Professor of Neurobiology and of Obstetrics, Gynecology, and Reproductive Sciences, director of the Yale Program in Cell Signaling and Neurobiology of Metabolism, and chair of the Section of Comparative Medicine.

"It's like pressing a car's brakes and accelerating instead," he said. "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. It fools the brain's central feeding system."

In addition to helping explain why you become extremely hungry when you shouldn't be, Horvath said, the new findings could provide other benefits, like helping cancer patients who often lose their appetite during treatment.

Researchers have long known that using cannabis is associated with increased appetite even when you are full. It is also well known that activating the cannabinoid receptor 1 (CB1R) can contribute to overeating. A group of nerve cells called pro-opiomelanocortin (POMC) neurons are considered as key drivers of reducing eating when full.

"This event is key to cannabinoid-receptor-driven eating," said Horvath, who points out that the feeding behavior driven by these neurons is just one mode of action that involves CB1R signaling. "More research is needed to validate the findings." Whether this primitive mechanism is also key to getting "high" on cannabis is another question the Horvath lab is aiming to address.

https://www.sciencedaily.com/releases/2015/02/150218072757.htm

Marijuana users weigh less, defying the munchies

April 19, 2019

Science Daily/Michigan State University

New evidence from Michigan State University suggests that those who smoke cannabis, or marijuana, weigh less compared to adults who don't.

The findings, published in the International Journal of Epidemiology, are contrary to the belief that marijuana users who have a serious case of the munchies will ultimately gain more weight.

"Over a three-year period, all participants showed a weight increase, but interestingly, those who used marijuana had less of an increase compared to those that never used," said Omayma Alshaarawy, lead author and an assistant professor of family medicine. "Our study builds on mounting evidence that this opposite effect occurs."

Results also suggest that new and persistent users are less likely to be overweight or obese, overall.

"We found that users, even those who just started, were more likely to be at a normal, healthier weight and stay at that weight," she said. "Only 15% of persistent users were considered obese compared to 20% of non-users."

Researchers used data from the National Epidemiologic Survey of Alcohol and Related Conditions and looked at the Body Mass Index, or BMI, of 33,000 participants, ages 18 and older, then compared the numbers.

While the actual weight difference among users and non-users was modest, around 2 pounds for a 5-foot-7-inch participant weighing about 200 pounds at the start of the study, the variance was prevalent among the entire sample size.

"An average 2-pound difference doesn't seem like much, but we found it in more than 30,000 people with all different kinds of behaviors and still got this result," Alshaarawy said.

So, what is it about marijuana that seems to affect weight? Alshaarawy indicated it's still relatively unknown but it could be several factors.

"It could be something that's more behavioral like someone becoming more conscious of their food intake as they worry about the munchies after cannabis use and gaining weight," she said. "Or it could be the cannabis use itself, which can modify how certain cells, or receptors, respond in the body and can ultimately affect weight gain. More research needs to be done."

Alshaarawy cautions, though, that marijuana should not be considered a diet aid.

"There's too many health concerns around cannabis that far outweigh the potential positive, yet modest, effects it has on weight gain," she said. "People shouldn't consider it as a way to maintain or even lose weight."

https://www.sciencedaily.com/releases/2019/04/190419094026.htm

New technique could more accurately measure cannabinoid dosage in marijuana munchies

March 15, 2016

Science Daily/American Chemical Society

As more states decriminalize recreational use of marijuana and expand its medical applications, concern is growing about inconsistent and inaccurate dosage information listed on many products, including brownies and other edibles. But now scientists report that they have developed a technique that can more precisely measure cannabis compounds in gummy bears, chocolates and other foods made with marijuana. They say this new method could help ensure product safety in the rapidly expanding cannabis retail market.

The researchers present their work today at the 251st National Meeting & Exposition of the American Chemical Society (ACS).

"Producers of cannabis edibles complain that if they send off their product to three different labs for analysis, they get three different results," says Melissa Wilcox, who is at Grace Discovery Sciences. "The point of our work is to create a solid method that will accurately and reliably measure the cannabis content in these products."

More than 30 states and the District of Columbia have either decriminalized cannabis or have allowed legal medical access to it. One recent study has shown that where marijuana edible products are legally available, labeling is at best inconsistent and at worst misleading. In fact, researchers who recently analyzed cannabis products legally purchased in three U.S. cities found that only 17 percent of the tested edibles containing marijuana had labels that accurately listed the amount of tetrahydrocannabinol, or THC, the active ingredient in marijuana that causes the substance's "high." More than half had detectable levels of another marijuana compound called cannabidiol, or CBD. This substance, which can be used as a pain-reliever and an anti-inflammatory without mind-altering effects, wasn't listed on most of these labels.

These discrepancies are important. Edible marijuana can be more potent and can have longer lasting effects than if it is smoked because of how it is metabolized in the body, says Jahan Marcu, Ph.D., who is at Americans for Safe Access and is vice-chair of the newly formed ACS Cannabis Subdivision. It also takes longer for a person eating a marijuana-containing snack to feel its effects.

"It's a lot easier for an individual to control their dose when smoking," Wilcox says. "The effects of edibles can take a while to happen. You eat them, and then wait to see how you feel in an hour or two. If you ingested too much, you could be in for an unexpectedly bad experience."

Most marijuana edibles are currently analyzed using a device called a high performance liquid chromatograph, or HPLC. But there's a problem using this technique.

"These machines were never designed for you to inject a cookie into them," Marcu says. "The sugars, starches and fats will wreak havoc on HPLC equipment. They can really muck up the works and lead to inaccurate results."

To overcome this problem, Wilcox, Marcu and colleagues placed food samples infused with cannabis into a cryo-mill with dry ice or liquid nitrogen. Then they added abrasive diatomaceous earth -- a silica-based compound sometimes used to keep snails out of gardens -- and ground the mixture to create a homogenous sample. They separated out the various chemical components using a technique called flash chromatography. This allowed them to inject liquid containing only the cannabinoids into an HPLC for analysis. The researchers concluded this process could yield far more accurate and reliable measurements of THC and/or CBD levels in an edible product than was previously possible.

The team is still evaluating their preliminary results and determining whether this technique will work with all cannabis-infused food and drinks. But so far, it appears to accurately measure cannabis content in gummy bears, brownies, cookies and certain topical lotions. According to Marcu, the next step is to install this equipment into commercial labs and train technicians to use it on a larger scale.

https://www.sciencedaily.com/releases/2016/03/160315085618.htm