Cannabis and derivatives show promise in reducing weight and waist circumference, with nuanced effects on body fat

By Tarun Sai LomteReviewed by Susha Cheriyedath, M.Sc.Nov 8 2023

In a recent study published in the International Journal of Obesity, researchers examined the effects of cannabis on anthropometric measures.

Obesity remains a significant global public health concern, with about 650 million adults affected, per the World Health Organization (WHO). Obesity results in metaphysical changes and chronic conditions that reduce life expectancy. Obesity-related complications are linked to excess body fat, an inflammatory condition that disrupts body functioning, resulting in cardiac, vascular, hemodynamic, skeletal, and cerebral malfunctions.

Study: Effect of cannabis and subproducts on anthropometric measures: a systematic review and meta-analysis. Image Credit: oatawa / Shutterstock

Various strategies have been described to reduce fat mass and, thereby, obesity. These include improvements in physical activity standards, adoption of healthy eating guidelines, drug interventions, and surgical interventions. In recent years, Cannabis sativa has been used to treat/relieve symptoms of some diseases.

Although it is well tolerated in some conditions, adverse effects have been frequently reported for psychiatric disorders with long-term use. Various diseases have been linked to the therapeutic or recreational use of cannabis. Nevertheless, the effects of cannabis and its sub-products are poorly understood.

About the study

The present study assessed the effects of cannabis and derivatives on anthropometric measures. The researchers searched Medline, Cochrane Library, Web of Science, and Embase databases for randomized controlled trials evaluating cannabis use and anthropometric changes in obese adults. Reviews, editorials, protocols, animal or in vitro studies, and those with populations under 18 years were excluded.

The intervention was the use of cannabis or its sub-products as therapeutic agents. Outcomes were changes in body weight, waist circumference (WC), body mass index (BMI), and body fat percentage. Data on study design, follow-up duration, participant characteristics, cannabis dosage, changes in obesity indices or indicators, data acquisition methods, findings, and limitations were extracted from eligible studies. The risk of bias was evaluated using the Joanna Briggs Institute critical appraisal tool.

The team performed a meta-analysis using a random-effects model to examine the relationship of cannabis use with changes in anthropometric indices or indicators. The Cochran Q test and I-squared statistic were used to assess the heterogeneity of studies. Forest plots were used to visualize treatment effects. Further, sub-group analyses were performed by the type of cannabis and follow-up duration.

Findings

The preliminary search yielded 2,620 hits. After deduplication and title/abstract screening, 2,560 articles were excluded. Overall, 27 studies were selected for systematic review; of these, 12 were included in the meta-analysis. The studies comprised 4,394 participants aged 18-70 and had a follow-up of up to 1,338 days.

The studies were performed in France, the United Kingdom (UK), the United States (US), Canada, Finland, Argentina, Portugal, Sweden, Iran, Holland, Spain, and Switzerland. Cannabis products included rimonabant, hemp oil, cannabidiol, β-caryophyllene, and Δ9-tetrahydrocannabinol (THC) and its analogs, among others. Studies tested varying doses of cannabis products.

However, some studies did not specify the dosage of hemp oil, β-caryophyllene, cannabidiol, and Δ9-tetrahydrocannabivarin (THCV). Participants who used cannabis and its products had reduced weight by 1.87 kg and WC by 2 cm. By contrast, BMI showed a marginal decline, whereas body fat increased by 0.58%. There was a higher weight reduction in a sub-group that used cannabinoid receptor 2 (CB2) antagonist/agonist and in studies with a longer follow-up (> one year).

Likewise, higher BMI reduction was evident in participants who used CB1 antagonist/agonist and in studies with a follow-up longer than one year. The sub-group using CB1 antagonist/agonist showed a greater decrease in WC. Further, the use of cannabis oil resulted in a low reduction in body fat, whereas other cannabis products increased body fat, especially the CB1 antagonist/agonist.

Conclusions

Taken together, the use of cannabis and sub-products reduced WC and body weight. Sub-group analyses indicated a higher BMI reduction with a longer follow-up. Changes in body fat were inconsistent across studies due to the fact that there were fewer studies available. Overall, while reductions in WC, body weight, and BMI were evident with cannabis use, the findings should be interpreted with caution, given the methodological limitations. Further research on the effects of cannabis in conjunction with dietary interventions or physical activity can offer additional insights into obesity prevention.