The sale of junk food — ice cream, burgers, and chips — increased after recreational cannabis was legalized at a state level in the US. Not too surprising, right?

Cannabis’ tendency to increase appetite, colloquially known as “the munchies,” is caused by its primary active element, the psychotropic cannabinoid THC. (CBD, on the other hand, appears to be associated with decreased appetite.)

Far more surprising than junk food sales is whether, considering all of the above, consuming cannabis leads to weight gain. The available research says it doesn’t — in fact, marijuana users actually tend to weigh less than non-smokers.

What The Current Research Says

One 2011 review that initiated much of the conversation about cannabis and weight loss found that obesity rates were higher in people who didn’t use cannabis in comparison to people who used cannabis at least three days per week.

In a 2016 study, researchers found that cannabis users have lower rates of metabolic syndrome. Metabolic syndrome is a cluster of conditions causing heart disease and stroke including obesity, high blood sugar, blood pressure, and cholesterol.

In a 2015 study, researchers explored the effects of chronic cannabis use on body weight in mice. Lean and overweight mice were given THC for four weeks and also fed a high-fat diet. The results showed that THC reduced weight gain, fat mass, and energy uptake. Interestingly, these results were not true for the lean mice. The researchers believe that this difference may be caused by the effects that marijuana use has on gut bacteria, which are responsible for food breakdown.

One meta-analysis looking at the association between cannabis use and body mass index (BMI) found that cannabis users had significantly lower BMIs and obesity rates compared to non-cannabis users. What is perplexing is that cannabis users consumed more calories on average.

Some research suggests that short-term versus long-term marijuana use changes the effects on weight gain. Short-term cannabis use is associated with weight gain, while long-term cannabis use may be protective against weight gain.

In one three-year prospective study based on cross-sectional and preclinical studies, researchers found a clear inverse relationship between cannabis use and BMI, meaning cannabis use is associated with lower BMI.

Decreases Stress

Research has shown that people over-consume food when they are stressed. Emotional eating as a form of stress-relief can be problematic and lead to weight gain. Cannabis is a well-known stress reliever, and so in some cases, alleviating stress with cannabis may help one consume fewer calories and therefore lose weight.

Increases Metabolic Rate

Some evidence shows that marijuana may improve your metabolic rate through activating one of the two major endocannabinoid receptors. Those receptors, CB1, are known to play an important role in the endocannabinoid system’s regulation of metabolism and food intake. Research is ongoing about how blocking CB1 receptors could contribute to weight loss treatment.

Lowers Alcohol Consumption

One study found that U.S states saw a 15% decrease in alcohol sales after cannabis legalization. Alcohol is known to be associated with an increased prevalence of obesity. Reducing the consumption of calorically dense alcoholic beverages may, therefore, help people lose weight.

What about CBD?

Cannabidiol (CBD) is a cannabinoid that is widely-used in treatment for a variety of health conditions, but lacks the psychotropic qualities of THC. Because of this, it is widely available including in areas where marijuana legalization has not been pursued.

But what does the research say about using CBD for weight loss? Research on human subjects is still lacking, so any conclusions should be taken with a grain of salt, but studies on rodents have provided some indication of the potential weight loss qualities of CBD.

A 2011 clinical study performed on rats found that injections of CBD “produced significant decrease in body weight gain.” The researchers stated that the results “suggest that CBD has the ability to alter body weight gain.”

Another study carried out on rats in 2012 found that CBD had both the effect of increasing appetite and decreasing overall feeding.

The Bottom Line

Using marijuana appears to be associated with having a lower body weight. Whether cannabis helps you lose weight, rather than just being associated with having a lower body weight, is still unknown. It’s entirely possible that some aspects of cannabis might promote weight loss while others promote weight gain. More clinical trials are needed to determine whether cannabis causes weight loss before it can be recommended as a weight loss aid.

