Among adolescent cannabis users, more lifetime cannabis use was associated with higher BMI and greater likelihood of being overweight or obese, and decision-making ability did not moderate this relationship.
Read this if you are a teen or parent of a teen who uses cannabis and want to understand the relationship between cannabis and weight.
More lifetime cannabis use was associated with higher BMI in teens even after controlling for depression, alcohol, and nicotine.
What the researchers found
In a sample of 238 adolescent cannabis users aged 14 to 18 (77% Hispanic), researchers found that greater lifetime cannabis use was associated with higher body mass index and a greater likelihood of being classified as overweight or obese.
The researchers hypothesized that decision-making abilities might moderate this relationship, since impulsive decision-making could lead to both more cannabis use and poorer dietary choices. However, decision-making performance did not interact with cannabis use to predict BMI, and was not independently associated with BMI either.
The association between cannabis use and higher BMI held even after controlling for depression, alcohol use, nicotine use, race, ethnicity, and IQ.
Why it matters
The relationship between cannabis and body weight is complex and contested. While some adult studies link cannabis use to lower BMI, this study found the opposite pattern in adolescents. This age-specific difference is important because adolescent weight trajectories have lifelong health implications.
The numbers in context
238 adolescent cannabis users. More lifetime cannabis use was associated with higher BMI. The relationship was robust after controlling for depression, alcohol, nicotine, race/ethnicity, and IQ. Decision-making was not a moderator.
How the study worked
Cross-sectional study of 238 adolescent cannabis users (ages 14-18, 56% male, 77% Hispanic) without significant developmental, neurological, or psychiatric disorders. Decision-making was measured using a validated behavioral task. BMI and weight classification were the outcome measures. Analysis controlled for multiple potential confounders.
What this study cannot tell us
Cross-sectional design prevents determining causation. The sample was predominantly Hispanic, limiting generalizability. The study only included cannabis users, so it cannot compare users to non-users. Physical activity and detailed dietary data were not measured. The decision-making measure may not capture all relevant aspects of impulsivity.
How to read the evidence
Moderate evidence from a well-controlled cross-sectional study with a reasonable sample size, though the cross-sectional design limits causal conclusions.
When this study was published
Published in 2016. The cannabis-BMI relationship continues to be studied with mixed results.
The bigger picture
Adult population studies have generally found that cannabis users have lower BMI than non-users, despite the stereotype of cannabis-induced overeating. This study in adolescents found the opposite direction, suggesting that the cannabis-weight relationship may differ by age, or that adolescent cannabis users differ from adult users in ways that affect weight.
Questions still open
- Why does the cannabis-BMI relationship appear to differ between adolescents and adults? Is the association driven by cannabis-induced appetite increases, lifestyle factors associated with adolescent cannabis use, or confounders not measured? Would longitudinal tracking show weight changes with cannabis use onset?
Common questions
Does cannabis cause weight gain in teens?
Why do some studies say cannabis users are thinner?
Read the original research
Decision-Making Does not Moderate the Association between Cannabis Use and Body Mass Index among Adolescent Cannabis Users.
Journal of the International Neuropsychological Society : JINS, 22(9), 944-949
Citation
Ross, J Megan; Graziano, Paulo; Pacheco-Colón, Ileana; Coxe, Stefany; Gonzalez, Raul. (2016). Decision-Making Does not Moderate the Association between Cannabis Use and Body Mass Index among Adolescent Cannabis Users.. Journal of the International Neuropsychological Society : JINS, 22(9), 944-949.
Explore the wider topic
- How to Talk to Your Teenager About Weed (Without Losing Them)
- My Kid's Friends Smoke Weed: A Parent's Guide
- I Smoke Weed But Don't Want My Kids To: Navigating the Hypocrisy
- Quitting Weed as a Parent: Why It Is the Hardest and Most Important Quit
- Quitting Weed as a Teen or Young Adult
- My Kid Is Smoking Weed: A Parent's Guide