Cannabis users are less likely to be overweight or obese

A study found that despite the common characteristics of experiencing the famous “munchies” (increased appetite) after adult cannabis use, users tend to weigh less and are less likely to be obese.

Research estimates that over 22 million people in the United States aged 14 and older regularly use cannabis, and more adults and seniors are adopting the habit. 

Cannabis: adult use and medical use 

The majority of adults in the U.S. who regularly consume marijuana represent 90% of adult users, while only the remaining 10% use it for medical purposes. 

Increased appetite vs. weight gain 

One of the physiological effects of marijuana is increased appetite, or what is popularly known as the munchies. Although it may seem intuitive that an increase in appetite leads to weight gain, current epidemiological studies suggest that cannabis users are less likely to be obese. 

Investigating the association 

A team of researchers from Michigan State University (MSU) in the U.S. decided to investigate this issue further, examining whether people who regularly consume marijuana are more likely to gain weight. Omayma Alshaarawy, Ph.D., assistant professor of family medicine at MSU, led the research, which appears in the International Journal of Epidemiology. 

Alshaarawy and colleagues examined data from a prospective study called the National Epidemiological Survey on Alcohol and Related Conditions (NESARC).  

The NESARC included 33,000 participants from the U.S. aged 18 and older who completed computer-assisted interviews about cannabis use and their body mass index (BMI) between 2001 and 2005. 

The researchers applied general linear modeling to study the relationship between Body Mass Index (BMI) and marijuana use. By the end of the study period, 77% of participants had never smoked cannabis, 18% had stopped, 3% were just starting, and 2% were “persistent users.”

Cannabis users have lower BMI 

The study found that, overall, cannabis users were less likely to be overweight or obese. “Over a 3-year period, all participants experienced weight gain, but curiously, those who used cannabis had a smaller increase compared to those who never used,” reports the study's lead author. 

Alshaarawy acknowledges that the research findings may seem counterintuitive, given that marijuana increases appetite. “Our study is based on growing evidence that this opposite effect occurs,” she says. 

Lower BMI found among new and persistent users 

“We found that users, even those who just started, were more likely to have a normal and healthier weight and to maintain that weight. Only 15% of persistent users were considered obese, compared to 20% of non-users.” 

The researcher continues to explain that while the difference in BMI between cannabis users and non-users was not very large, it is significant that researchers found this trend across the sample size. 

Does cannabis help you lose weight? 

Although this study is observational and cannot infer causality, the lead investigator offers some opinions on the mechanisms that may explain the association between lower BMI and cannabis use. 

“It could be something more behavioral, like someone becoming more aware of their food intake while being concerned about the munchies after cannabis use and weight gain,” she says. 

“Or it could be the cannabis use itself, which may modify how certain cells, or receptors, respond in the body and may ultimately affect weight gain. More research needs to be done,” concludes the researcher. 

Until we know more about the underlying mechanisms, however, Alshaarawy warns against the dangers of using cannabis to lose weight. 

“There are many health concerns surrounding cannabis that far outweigh the potential positive effects, albeit modest, that it does not have weight gain. People should not consider this as a way to maintain or even lose weight,” she concludes.