Does Smoking Weed and Not Eating Help Lose Weight?

The short answer is yes, it does—but it depends on what kind of help you’re looking for.

One of the primary purposes of the Food and Drug Administration (FDA) is to protect public health by ensuring that the products we buy and the foods we eat are safe. The agency accomplishes this goal by regulating the production of food and beverages, both of which affect weight management.

Since the 1960s, cigarette smoking in the U.S. decreased considerably, dropping from 28% to 22% of the population. Yet, despite this decline, the number of people who are overweight or obese has increased significantly, rising from 12% to 29% between 1960 and 2016. This indicates that reducing cigarette smoking may have actually contributed to the obesity epidemic in the country.

Although it’s well-established that a healthy diet and regular exercise are effective methods of weight loss, some individuals may be finding that weed helps them with their weight loss journey. After all, marijuana’s primary active ingredient, tetrahydrocannabinol (THC), is a potent appetite suppressant.

While there’s plenty of scientific evidence that consistently supports the use of cannabis as a therapeutic tool, it’s not always clear how much weight these individuals are actually losing. To shed some light on this subject, we conducted a quick review of the current available scientific literature on the topic and found that, in general, smoked cannabis is better for weight loss than oral cannabinoids—yet, the differences were often quite small.

Does Regular Cannabis Use Help With Weight Loss?

In a study published in March 2020 in the journal Obesity Science & Practice, researchers from the University of Guelph in Canada compared the weight loss effectiveness of oral cannabinoids (i.e., THC and cannabinoids) with that of smoked cannabis in a group of overweight and obese individuals. Though both products reduced weight, the participants who smoked cannabis experienced a greater decrease in body mass and body mass index (BMI).

In this study, participants took part in a weight management program and were randomly assigned to receive either THC (0.35 mg/kg), oral cannabinoids (0.125 mg/kg), or placebo every other day for 12 weeks. The dosage of THC and oral cannabinoids was determined based on the average weight and height of the participants to provide an average dose for an adult human. After 12 weeks of treatment, the researchers found that the average weight gain suppression in the cannabis group (–3.4 kg) was greater than that of the oral cannabinoid group (–1.7 kg) or the placebo group (–1.1 kg). Furthermore, the participants who received cannabis had a greater decrease in BMI than those who received oral cannabinoids or placebo. These results were even more significant when participants were stratified according to their BMI at the beginning of the study.

This randomized, double-blind, placebo-controlled trial (RCT) directly supports previous research that found similar results. In an RCT published in 2018 in the journal Molecular Psychiatry, researchers from the Medical University of Graz, Austria compared the effects of THC (5 mg/day) and an inert placebo on 24-hour weight fluctuations in a sample of overweight and obese individuals. Though both THC and placebo therapy decreased 24-hour weight, as expected, participants who received THC reported less food craving and consumed fewer calories than those who received the placebo.

In another trial that focused on the effects of THC on food intake, satiety, and weight loss in human participants, researchers from the University of Guelph in Canada published the results of a randomized, double-blind, placebo-controlled trial in March 2020 in the American Journal of Therapeutics. In this trial, 14 overweight or obese participants were randomized to receive either an oral placebo, an oral THC (2.5 mg), or a THC (2.5 mg) inhalation every day for two weeks. The dosage of THC was selected based on previous similar studies and was determined to provide a sufficient dose to activate cannabinoid receptors in the brain while avoiding the adverse effects associated with higher dosages. After two weeks of treatment, the researchers found that the average weight loss in the oral THC group (–1.6 kg) was significantly greater than that of the placebo group (0.1 kg) or the inhalation THC group (0.2 kg).

These studies suggest that, when compared to an oral placebo, cannabis oil may be an effective treatment for obesity. However, since these studies only examined the effects of cannabis on body weight, we cannot determine whether or not it helps with fat reduction or simply reduces the appetite for junk foods.

How About Different Strains Of Weed?

Weed is generally available in three forms: dried flower, wax, and liquid. Each of these forms contains a unique blend of cannabinoids and other compounds that give the substance its characteristic taste and smell. The different forms of weed influence the manner in which it is absorbed by the body and, as such, may impact weight loss differently. For example, though all forms of weed reduce appetite and increase energy levels, the liquid form may be most effective for those who are looking to lose weight.

In an early study that examined the effects of three different strains of marijuana (i.e., Jack Herer, Durban Poison, and San Francisco Bug) on body fat in a group of overweight and obese men, researchers from the University of Guelph in Canada found that, compared to the placebo group, all three strains reduced waist circumference, body fat, and food intake and increased activity levels. However, the data suggest that the effect of the different strains on these variables is relatively small.

In November 2019, researchers from Canada’s York University published the results of a study that examined the effects of three different types of cannabis (i.e., sativa, indica, and ruderalis) on metabolism and appetite in a group of overweight and obese men. Interestingly, the researchers found that both indica and ruderalis strains increased energy expenditure, while sativa reduced food intake and increased activity levels—all suggesting that these strains may have beneficial effects on weight loss.

When Does It Help?

Though it’s not always clear from the literature when or in which situation cannabis is more effective for weight loss, there is some evidence that it may be more effective in the morning. According to studies, THC is more effective when administered in the morning, whereas CBD is more effective when administered in the evening.

In July 2019, researchers from Italy’s Sapienza University of Rome presented the results of a study that examined whether or not morning or evening dosing of CBD (i.e., 200 mg) or a placebo would be more effective at reducing body weight in a group of overweight and obese individuals. The researchers randomized the participants to receive either CBD in the morning or in the evening and, in both cases, found that at least eight hours had passed since the administration of CBD or placebo. Even more interesting, the researchers found that the group that received CBD (morning or evening) lost more weight than those who received a placebo. This suggests that CBD is more effective when administered in the morning or in the evening, though the exact opposite may be true as well.

The literature doesn’t always provide us with an answer to this question, but it’s an interesting aspect to consider since many individuals benefit from taking their supplements in the morning. Perhaps there’s something to be said for taking one’s weight loss supplements in the morning and waiting to take them in the evening.