Does Weed Make You Gain Weight?

Marijuana can lead to weight gain due partly to THC’s ability to increase the appetite-stimulating hormone ghrelin. This mechanism gives high-THC strains (cultivars) their signature hunger pang effects, known as the munchies. THC also amplifies tastes and flavors while increasing pleasure, making eating a more enjoyable experience.

Still, weed itself does not make you gain weight. Marijuana flower has a negligible number of calories if you eat it raw. And smoking or vaporizing weed is a calorie-free experience. Additionally, marijuana users have a lower body mass index on average than non-smokers, despite the aforementioned cravings.

Theoretically, a THC-induced grumbling stomach and heightened senses create the perfect storm for excessive overeating and weight gain. But the data doesn’t align.

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Marijuana and Weight Gain: What the Research Says

THC’s crave-inducing behavior lies in its ability to bind with endocannabinoid (CB1) receptors in the brain, stomach, and intestinal tissue, making it particularly influential on metabolic regulation, increased appetite, and food enjoyment. By binding with these receptors, THC stimulates the hunger hormone ghrelin while heightening sensitivity to smell and taste.

Synthetic THC and Hunger

Due to THC’s proven mechanisms, pharmaceutical companies have developed various synthetic THC drugs for clinical weight gain. Dronabinol, an FDA-approved pharmaceutical, was designed to help underweight people with HIV, eating disorders, and cancer increase their appetite and body mass index. But clinical analyses failed to prove that dronabinol is significantly more effective than alternative treatments.

One study showed dronabinol exhibited modest benefit over placebo for underweight people with HIV. Another study comparing dronabinol to an alternative appetite stimulator (megestrol) found that people with cancer taking megestrol gained nearly three times more weight than THC patients.

The Munchies and Weight Gain

Marijuana weight gain research also reveals context matters regarding the munchies. Studies on healthy adults, for example, indicate that THC dosage is a significant factor in caloric intake. One behavioral analysis found that low-dose marijuana consumption has no relevant effect on food intake, while higher doses are associated with increased calories — likely due to snacking between meals.

Even more perplexing, major epidemiological studies on healthy adults find that marijuana users tend to have lower body mass indexes than nonusers. A 15-year longitudinal study comparing 2,255 people with marijuana histories to 1,365 non-smokers revealed that while marijuana users generally consumed more daily calories, they also weighed less.

An analysis of two extensive epidemiological studies showed even more statistically dramatic results. Non-users experienced 22% and 25.5% obesity rates in the subsequent studies, while obesity rates among marijuana users were 14.3% and 17.2%.

These findings make no sense on the surface. In fact, these findings imply weed may somehow lead to weight loss in some people.

Can Weed Cause Weight Loss?

From biological to behavioral, scientists have various theories to explain marijuana’s perplexing association with weight loss:

• Short-term versus frequent long-term use: Consuming marijuana initially stimulates CB1 receptors, which increases appetite while intoxicated. But a meta-analysis revealed that long-term regular cannabis use actually downregulates the CB1 receptor for several weeks after consumption. This action directs the body to start reducing energy (aka calorie) storage and increasing metabolic rates, potentially leading to weight loss.
• Overall substance use: Marijuana users are more likely to abuse alcohol and other drugs like sedatives, stimulants, and opiates. Stimulants, in particular, are associated with decreased appetite and weight loss.
• Reward competition: One study found a negative relationship between marijuana use and body mass index in women who are overweight, meaning women with higher BMIs seemed to use less marijuana. Authors theorized this paradox occurred because drugs and food compete for the same brain reward centers. In other words, some people enjoy eating more than getting high.
• Broad spectrum regulation: Data indicates that low-weight individuals are more likely to gain weight with short-term chronic use than people of average or higher body mass indexes. Researchers believe this irony shows a “broad-spectrum” weight regulatory effect, where cannabis can help sick and thin individuals gain body mass while not impacting individuals with at or above “normal” BMIs.

How Other Cannabinoids Affect Weight

THC’s hunger-stimulating effects are legendary. But cannabidiol (CBD), marijuana’s prominent non-psychoactive cannabinoid, does not have the same effect. Another cannabinoid, THCV, might even counteract the munchies and rewire the brain.

CBD

A 2012 animal study found that CBD exposure reduced appetite in rats. A few years later, in 2016, researchers found preclinical evidence to support the claim. The 2016 study found that CBD converted white fat cells to brown fat cells. Brown fat, aka “good fat,” is a more active version that helps the body burn calories.

THCV

THCV is a minor cannabinoid known for its energizing and mental clarifying properties. Sometimes called “diet weed,” THCV may effectively combat obesity by suppressing the appetite and altering neural connectivity leading to a potentially lower BMI.

A prospective article in Molecular Biology revealed that 5-7.5 milligrams (mg) of THCV reduced appetite by inhibiting CB1 receptors, and 10-15 mg helped regulate blood sugar levels.

Another study revealed THCV’s weight-loss powers come partly from its ability to calm the brain’s default mode network (DMN). An overactive DMN causes excessive rumination about the past and future and correlates with obesity. This randomized, double-blind study showed THCV reduced the DMN’s resting rate while increasing connectivity in the cognitive control network. This action makes THCV relevant as a medication for obesity.

The Bottom Line

The relationship between marijuana use and weight gain is complex and varies depending on the individual, initial weight, frequency of use, and marijuana dosage. Some low-weight patients utilize medical marijuana and THC-based pharmaceuticals to increase body mass successfully. Other cannabis users lose or maintain weight, likely due to various factors, including THC-driven metabolic changes, diet choices, and overall lifestyle.

In addition to marijuana use, genetics, nutrition, and physical activity levels play a significant role in weight gain or loss.

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