Whether or not you’ve ever smoked weed, you’ve probably heard of the munchies — that overpowering drive to eat all the snacks after smoking weed.

But others swear that smoking weed not only makes them eat less, but also makes them lose weight.

Using marijuana may be associated with lower body weight, but it’s not as straightforward as it sounds.

Here’s a look at what we do and don’t know about the relationship between smoking weed and weight loss.

A lot of the noise around smoking weed for weight loss comes from a 2011 review of two surveys. The authors concluded that rates of obesity were higher among people who reported not using marijuana compared to rates among those who used marijuana at least 3 days a week.

Shortly before those results were published, a study examining the association between cannabis and obesity in young people made similar conclusions.

Most recently, a meta-analysis of the relationship between cannabis use and body mass index (BMI) showed that cannabis users had significantly lower BMIs and obesity rates but an increased calorie intake.

It’s important to remember that this research simply suggests there are some links between marijuana use and lower body weight. It’s unclear what’s behind this link, and there’s not enough evidence to say that using marijuana is an effective way to lose weight. Plus, using marijuana comes with its own risks and downsides (more on this later).

Experts have a few theories on why marijuana use is linked to reduced BMI and lower risks of obesity.

It can increase mobility

When used properly, marijuana may relieve symptoms of pain and stiffness. This means people with mobility issues may find that they can be more active when using marijuana.

It may cause some people to drink less

Some experts suspect that younger people who use marijuana may consume less alcohol than those who don’t. This means they’re not taking in calories from alcoholic drinks, which could contribute to lower BMIs.

It can lower stress

Stress eating is a very real thing. Studies show that people are more likely to overeat and reach for comfort foods when stressed.

It’s no secret that weed can ease anxiety and help calm you when you’re feeling stressed. Some believe that this might replace stress eating for some people.

It may improve sleep

Poor sleep can be a factor in weight gain. There’s some evidence that cannabis may improve insomnia. Plus, it may help reduce stress and pain, two of the main culprits behind poor sleep.

It may boost metabolism

There’s some evidence that cannabis interacts with cannabinoid receptor 1 , which plays a role in metabolism and food intake. High amounts of cannabis appear to increase metabolism and reduce energy storage, resulting in a lower BMI.

Using marijuana doesn’t cause sudden weight loss. But experts believe it may help with some underlying factors that can contribute to weight gain in some people.

Much more research is needed to fully understand the link between marijuana use and weight.

The research around marijuana and weight loss catches some people off guard because of the long-standing association between marijuana and major snacking.

Indeed, a recent study showed an increase in sales of junk food, which the authors largely defined as chips, cookies, and ice cream, in U.S. states where marijuana is now legal.

How can people be eating more and losing weight while smoking weed? Researchers are still trying to figure out the specifics, but a balancing act between two major cannabinoids in marijuana might offer some explanation.

THC, the psychoactive compound that produces weed’s “high,” has been shown to trigger hunger. It’s the reason why people sometimes use cannabis as an appetite stimulant.

CBD, on the other hand, seems to counteract certain effects of THC, including its appetite-boosting and mood-altering effects.

At first glance, the research might seem to suggest that smoking weed is a good way to lose weight. But there’s no evidence that using marijuana directly causes weight loss.

It might contribute indirectly by helping with certain issues, including chronic pain and poor sleep, that can contribute to higher body weight.

Plus, using marijuana isn’t without risks, especially if you smoke it.

Marijuana smoke contains many of the same irritants, toxins, and cancer-causing agents as tobacco smoke, according to the American Lung Association.

And because weed smokers inhale more deeply and hold the smoke in longer, they’re exposed to more tar per breath than cigarette smokers.

Over time, smoking weed damages your lungs and airways, reducing respiratory function and increasing your risk for lung infections and even lung cancer.

It can also weaken your immune system, which interferes with your body’s ability to fight disease.

Then there’s the whole issue of misuse and dependence. Up to 30 percent of users have some degree of marijuana use disorder, according to recent data. Younger people are especially at risk, particularly people who use marijuana before the age of 18.

Even though there’s some evidence that smoking weed may affect weight, a lot more research is needed.

Plus, smoking still does more harm than good, even if it’s just marijuana. Using marijuana through nonsmoking methods may offer some health benefits, but it’s not recommended for weight loss.