Marijuana causes munchies. So will CBD-containing food lead to weight gain?

As laws are relaxed, marijuana will become more common in food products. Photo/Getty Images.

As a dietitian, I always receive an influx of New Year's emails predicting upcoming food trends. This year, several experts have forecast an increase in foods and beverages containing cannabidiol, a chemical compound found in cannabis plants. More colloquially called CBD, cannabidiol has been approved by the Food and Drug Administration to treat some forms of epilepsy and shows potential in treating pain, nausea, anxiety and depression - without making users high.

But what about its effect on hunger? After all, smoking or ingesting cannabis is associated with the munchies. Does CBD have the same effect? Could a trend toward CBD-infused foods lead to weight gain? And how might CBD affect people who have conditions that make it difficult to keep weight on (such as those with HIV/AIDS, cancer, eating disorders or depression)? I consulted some experts.

To understand their answers to these questions, first, a quick tutorial. Cannabis plants contain more than 100 cannabinoids, although the therapeutic and psychoactive effects of most of them aren't yet known. The two most-researched cannabinoids are CBD and tetrahydrocannabinol, or THC, which is the main psychoactive cannabinoid. THC makes you high; CBD doesn't. And, it turns out, they affect appetite in different ways.

THC produces the well-known cravings for sweet and fatty foods through several mechanisms, according to the experts I consulted. First, "THC increases the hormone ghrelin, which causes you to feel hungry," says Janice Newell Bissex, a registered dietitian and holistic cannabis practitioner in Melrose, Mass. If your stomach is empty, she says, you produce more of the hunger hormone ghrelin, which tells the brain to generate the sensation of hunger. But THC can increase ghrelin and trigger the feeling of hunger even if your stomach isn't empty.

Second, THC hits a part of the brain that controls hunger. "The appetite-promoting effect of THC is mediated by CB1 receptors located in areas of the brain involved in appetite control," explains George Kunos, scientific director at the National Institute on Alcohol Abuse and Alcoholism in the National Institutes of Health in Bethesda, Md.

And, third, THC boosts dopamine, the "feel-good" chemical in the brain, "so you get more pleasure from eating," Bissex says. "THC can increase the sense of smell and taste, so people are more inclined to want to eat."

CBD, by contrast, does not cause the munchies, the experts said. But it may boost appetite in a different way if it's added to foods and beverages or taken as a medication. "CBD helps relieve nausea and can calm your nervous system and digestive tract" Bissex says. "If you feel less nauseated, you may eat more. CBD also quells pain, and feeling less pain may also boost appetite." For that reason, it's often used by people with cancer, chronic pain or other medical issues. (Either CBD or THC - or both - can be found in medical marijuana products; the legality of CBD and THC products depends on the state in which you reside.)

If THC increases appetite, does that mean recreational cannabis users will weigh more than nonusers because they want to keep eating? You'd think so, but surprisingly the answer is no.

"Studies indicate that regular heavy cannabis users tend to be leaner than age- and gender-matched groups of nonusers," Kunos says.

Overall, cannabis use in the general population is actually associated with a lower body mass index. "Interestingly, cannabis may help increase weight in those who are low weight, but not in those who are normal or overweight," says Bissex.

The reason has not been definitively established, but may involve the amount of THC that someone is exposed to, says Kunos says. High doses of THC can suppress the number of CB1 receptors so that fewer receptors are stimulated, which could limit weight gain.

Marijuana will likely be added to smoothies in the future. Photo/Getty Images.

And, THC's hunger-boosting effect may signal hope for weight-loss efforts. Because researchers are able to figure out how cannabis increases appetite, it may help them develop products to reduce appetite, too. Some drugs are "inverse agonists," which means that they bind to the same area in the brain but produce an opposite response. Using this theory, researchers are investigating how to reduce, rather than increase, appetite using CB1 receptors.

In 2006, a drug called rimonabant held potential to be an effective inverse agonist to aid weight loss, but it had too many psychiatric side effects and was pulled off the market. Kunos's lab is working on an appetite-suppressant drug without the side effects.

So, are the food trends experts on to something? Will CBD be on the menu at your favourite restaurants and on store shelves where you buy groceries? That will depend on where you live. If you live in Oregon, California, New York or Colorado, you may very well be ordering CDB-infused beer, or buying CBD-enhanced sweets and pastries. You can rest assured that such products will not cause the munchies - but keep in mind that weight gain could result from consuming the beer, sweets and pastries themselves.

- Rosenbloom, a registered dietitian, is president of Words to Eat By, a nutrition communications company specialising in writing, nutrition education and recipe development. This article originally appeared on the Washington Post.