Marijuana smokers may have lower risk of obesity

French researchers have made a surprising link between somking cannabis and body weight. File photo / Thinkstock

A French study has found marijuana smokers may have a lower risk of obesity that those who don't use the drug.

Although a common side effect of the drug is the "munchies", the results of the study show the prevalence of obesity is lower among people who frequently smoke marijuana compared with those who have never inhaled.

Between 4 and 7 per cent of participants in these surveys reported using cannabis at least once in the last year.

Obesity was assessed using participants' body mass index (BMI).

The survey showed that about 22 to 25 per cent of people who don't smoke pot were obese, while 16 to 17 per cent of cannabis users were obese.

Obesity was less common among users who smoked pot more frequently. For instance, the NESARC survey showed about 14 per cent of participants who used cannabis three days a week or more were obese, the researchers said. Between 0.7 and 1.8 per cent of the sample smoked marijuana this frequently.

The researchers said they were surprised by their initial results, because they expected to find the opposite. So they examined a second sample of people, and got the same result. The two samples studied more than 50,000 people

Researchers at the Louis Mourier Hospital in France suggested the link could be because people who use cannabis also engage in other behaviors that lower their obesity risk, or smokers exercise more or have a specific diet that keeps them thin.

"From a personal point of view, I would be surprised that cannabis use is associated with a higher rate of physical activity, but this cannot be ruled out," researcher Yann Le Strat told website MyHealthNewsDaily.

Le Strat also suggested that components of cannabis may help people lose weight, adding that if this was the case, researchers should investigate which components these might be and try to put them into drug form.

Despite the results of the study, Le Strat emphasised that people should not smoke cannabis to lose weight as cannabis has well-known physical and mental health consequences, including an increased risk of psychosis.

"As an addiction psychiatrist, I see every day people struggling with cannabis dependence. I would not recommend smoking cannabis for any reason," Le Strat said.