In this study on cannabis and obesity, researchers found that men who used cannabis had a lower body mass index (BMI) than non-users.
It has often been a question of whether there is a link between marijuana and obesity. Findings in a new study published in the journal Psychosomatic Medicine suggest that long-term cannabis use is associated with a lower body mass index (BMI).
Body mass index is a measure of body fat based on height and weight. The measure is used to screen adults 21 years and older for weight categories that can increase the risk for serious health problems, including diabetes, heart disease, sleep apnea, and even cancer. A high BMI can be an indicator of unhealthy levels of body fat and obesity.
High body fat is a major health issue in the United States. More than one in three adults in the United States were considered to be overweight or obese, according to 2013-2014 data from the National Health and Nutritional Examination Survey. About one in 13 were considered to have extreme obesity.
To assess the association between long-term cannabis use and cardiometabolic risk factors like BMI, researchers from Arizona State University and the University of Pittsburgh used a longitudinal study design comprised of 253 men from the Pittsburgh Youth Study.
In this study of cannabis and obesity, the researchers examined cardiometabolic risk factors in the men for 25 years, from age seven to 32. Cannabis use was measured every year between ages 12 and 20, and then again at ages 26, 29, and 32.
The study, released online ahead of print, showed an interesting link between marijuana and body weight; it revealed that greater cannabis exposure was linked to a relatively lower BMI.
“Cannabis use is associated with lower BMI and lower BMI is related to lower levels of risk on other cardiometabolic risk factors,” the researchers concluded.
A person’s BMI can be calculated by dividing weight in pounds (lb) by height in inches (in) squared and then multiplying that value by a conversation factor of 703. A healthy BMI for adults is considered between 18.5 and 24.9. An adult with a BMI of below 18.5 is considered underweight, and a BMI between 25.0 and 29.9 is considered overweight. A BMI of 30.0 or above is classified as obese.
BMI does not measure body fat directly, but according to the Centers for Disease Control and Prevention appears to be “strongly correlated with various metabolic and disease outcome.” Medical professionals generally monitor a person’s BMI to screen for weight category because it is an inexpensive and easy-to-perform procedure.
Cannabis and Cardiometabolic Risk Factors
The new study from Arizona State University and University of Pittsburgh researchers also revealed a positive link between cannabis use and a smaller waist to hip ratio (WHR), healthier cholesterol levels, lower blood pressure, lower fasting glucose and triglycerides, and fewer metabolic syndrome criteria.
“With exception of BMI, cannabis users’ mean levels on cardiometabolic risk factors were generally below clinical cutoffs for high risks,” the study authors write. “Most associations between cannabis use and cardiometabolic risk factors remained after adjusting for tobacco use, childhood [socioeconomic status], and childhood health.”
After adjusting for adult BMI, these associations were no longer apparent. According to the researchers, this suggests that “that cannabis users’ relatively lower BMI might explain their lower levels of risk on other cardiometabolic risk factors.”
Previous Findings on Cannabis and Obesity
The new study’s findings are consistent with those of previous studies concluding marijuana use is associated with lower body fat levels.
Researchers from Oregon’s Health and Science University in 2017 found that those who consumed cannabis more than five times per month had an on average lower BMI compared to non-users. A 2016 study showed daily marijuana use to be associated with lower BMI in both men and women.
A team of Canadian cannabis and obesity researchers in 2015 used data on 786 adults to discover “cannabis use was associated with lower BMI” and that this association “was mediated through its influence on weight.”
The significance of a potential healthy relationship between cannabis and obesity cannot be understated. In 2017, a researcher from Indiana University South Bend found evidence suggesting that cannabis use reduces premature deaths. In his research review, Dr. Thomas M. Clark, Professor and Chair of the university’s Department of Biology, cited evidence of cannabis use leading to “significant positive health outcomes.” Clark specifically highlighted studies linking cannabis use to lower rates of obesity. These lower rates of obesity, he explained, would subsequently lead to lower rates of premature deaths related to cancer, cardiovascular disease, chronic kidney disease, diabetes mellitus, and Alzheimer’s disease.
How Cannabis and Obesity May Be Related
Researchers are still learning more about how cannabis use may encourage a more healthy body fat percentage. The relationship between cannabis-derived cannabinoids and the body’s metabolic processes are still unclear.
One hypothesis regarding cannabis and obesity suggests that cannabis-derived cannabinoids may influence one of the body’s major self-regulatory networks. This network, the endocannabinoid system (ECS), is tasked with regulating a wide array of functions, some of which influence a person’s body fat percentage– metabolism, energy balance, and appetite.
Some researchers believe obesity could be related to a problem with the ECS. In one study, cannabis and obesity investigators found evidence that an unbalanced energy intake triggered a dysfunction in the ECS and cause it to be overactive. An overactive ECS may have contributed to fat accumulation and eventually obesity.
It’s known that cannabis cannabinoids interact with the ECS through cannabinoid receptors found in the brain, central nervous system, and peripheral nervous system. Researchers have suggested that altering the ECS through the interaction between cannabinoids and cannabinoid receptors may encourage the network to perform more optimally and more effectively regulate the functions related to the storing of body fat.
This theory is supported by evidence showing that in underweight individuals, cannabis use can actually stimulate healthy weight gain. Together, these findings indicate that cannabis-derived cannabinoids do not always elicit weight loss or weight gain. Rather, they likely encourage the ECS to better regulate a healthy body weight.
Cannabis for Treating Obesity?
While 32 states have legalized the use of medical marijuana, none have specifically approved doctor-approved cannabis use for the treatment of obesity. Patients interested in obtaining and using cannabis through their state’s medical marijuana program would need to be diagnosed with a qualifying condition related to their obesity, such as diabetes, chronic joint pain, or other conditions.
In 10 U.S. states, adults 21 years and older can legally access and use marijuana for obesity without first acquiring a recommendation from a doctor.