Does Marijuana Cause Weight Loss?

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A prevailing stereotype of marijuana users is that they always have "the munchies." Research suggests that long-term cannabis use can lead to weight gain, particularly in men. That being said, its effects on weight gain differ by plant strain, dose, route of administration, and frequency of use, among other factors.

But a growing body of evidence shows that marijuana use can actually produce an inverse effect. Some studies show that regular users are less likely to experience weight gain and obesity compared to those who do not use marijuana. In fact, marijuana can even help some people to lose weight. Here's a closer look at what both sides of the research have to say.

Marijuana and Weight Gain

When it comes to weight gain and marijuana use there are a few different factors to consider. Those who get the munchies may crave unhealthy processed foods high in added sugar, sodium, and saturated fat, which are likely to cause weight gain. Other people may simply experience an increase in appetite but are not getting enough exercise and are taking in more calories than they burn.

In addition, different strains of marijuana will have varying concentrations of cannabinoids, including tetrahydrocannabinol (THC) and cannabidiol (CBD), and terpenes. These psychoactive chemicals act on the CB1 and CB2 receptors in the brain that make up the endocannabinoid system. These receptors play a key role in regulating appetite, stress, and pain sensations, and combined with other factors, can impact weight gain.

Marijuana Can Stimulate Appetite

Whether smoked or eaten, cannabis affects the neurobiological circuits that control appetite, causing a temporary increase in appetite, resulting in the munchies. According to a 2015 study from the Yale University School of Medicine, activation of the CB1 receptor from THC increases feeding behaviors and leads to decreased activity of the neurons responsible for feelings of satiety.

The effect is known to be considerable and one that can be used in medical practice to stimulate appetite in those with cancer, advanced HIV infection, and other serious medical conditions. 

Appetite stimulation doesn't inherently translate to weight gain, however. Within the HIV population, marijuana may help stifle weight loss but does little to reverse the wasting that can accompany serious illness. This suggests that appetite stimulation is only part of what triggers weight gain in certain cannabis users.

Reduced Athletic Performance

Cannabis users have been observed to show marked decreases in performance, steadiness, reaction time, and psychomotor performance for up to six hours following use, all of which affect a person's ability to drive.

Similar effects may result in decreased athletic performance, particularly for the average person. Cannabis use often leads to a decrease in motivation, which may make some people less inclined to exercise for the same duration or with the same level of intensity as they normally would.

This can make exercises like rock climbing or heavy-weight lifting more dangerous, a deterrent, which, along with the muscle-relaxing properties of particular strains, may promote weight gain simply by decreasing a person's capacity for physical activity. According to research, THC significantly elevates the resting heart rate (RHR) and blood pressure during and after physical training, decreasing a person's overall tolerance for exercise.

That said, cannabis has also been shown to decrease pain and inhibit exercise-induced asthma, which could make it a helpful adjunct to simple exercises that chronically ill patients otherwise couldn't do. However, if a significant number of pain patients switch to medical cannabis for pain management in places where it is legal at the state level, it will become important to research these effects more thoroughly.

While light exercise may not be negatively affected, cannabis use is unlikely to lead to peak performance.

Marijuana and Body Mass Index (BMI)

Peripheral cannabinoid receptors activated by THC are involved in regulating pancreatic function and lipid metabolism. According to research published in 2015 by the American Diabetes Association, compared to non-users, cannabis smokers tend to have a higher percentage of abdominal visceral fat and increased insulin resistance, in addition to lower plasma HDL cholesterol.

Among healthy people who regularly use cannabis, there is a significant difference in how the drug influences weight if you are male or female. For instance, a study conducted in 2015 by researchers at the University of Montreal found that cannabis use triggered significant and consistent weight gain in men, but not in women. Although the reason for this remains unclear, the scientists suggested that differences in neurobiological targets, as well as general psychology, played a part.

Some research suggests that strains of cannabis that are high to moderately high in THC are more likely to trigger weight gain, particularly among regular users.

Can CBD Oil Affect Weight?

Cannabidiol, or CBD, is an active ingredient in marijuana that produces a biological response. Unlike THC, CBD does not induce the same mind-altering psychotropic effects associated with marijuana use. Increasing evidence shows that CBD may have both therapeutic and anti-inflammatory benefits including improved sleep, relief from anxiety, and reduced joint pain.

But research is mixed as to how CBD might impact weight. Some studies have found it may decrease appetite while others have found the opposite. One study showed that 30% of children who were treated with a CBD medication for epilepsy experienced an increase in appetite. But 53% of the subjects also reported an improvement in sleep, 71% cited increased alertness, and 63% saw an increase in mood, all of which are positive outcomes.

Some animal models have shown that CBD increases appetite at meals, but actually decreases overall food intake, suggesting that it promotes satiety. Other studies have indicated that CBD affects both lipid and glucose metabolism and may be effective for the treatment of obesity. A 2020 review of the current research published in Frontiers in Endocrinology concluded that not only does CBD have potential as a therapeutic agent, it may also help promote weight loss and offer a potential treatment for chronic diseases associated with obesity.

Current research suggests that CBD may be able to improve insulin resistance and symptoms of type 2 diabetes and metabolic syndrome.

Could Marijuana Cause Weight Loss?

Emerging research shows that marijuana use may lead to weight loss. A study published in 2019 in the International Journal of Epidemiology showed that cannabis users actually experienced less weight gain over a three-year period compared to non-cannabis users. The results indicate that subjects who quit using cannabis lost the least amount of weight (–0.81) compared to those who had just started using cannabis (–0.97). Regular users saw the greatest change in BMI with a 1.26 reduction.

Additionally, the results of an older study from 2011 show that marijuana users are less likely to experience obesity compared to those who do not use marijuana at all.

A Word From Verywell

The association between weight gain and marijuana use is anything but conclusive, but there is enough evidence to suggest that it can influence weight in certain people, especially frequent users who are male, who use cannabis strains higher in THC, or who have other risk factors for obesity or metabolic syndrome.

While other research posits that marijuana may help prevent weight gain in some people and reduce body fat in others, stronger evidence is still needed to determine exactly how marijuana affects body weight.

If you're looking to lose weight, ask your doctor for advice. Marijuana use should not be a substitute for a well-balanced diet and regular exercise. While marijuana may offer some benefits, keep in mind that it's not for everyone, especially those who struggle with addiction. Long-term use of marijuana has also been shown to cause damage to the lungs and lead to impaired cognitive function.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

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Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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