Does the science hold up?
Even though cannabis use is stereo typically associated with “the munchies,” preliminary evidence does suggest that THC and other cannabinoids may in fact be responsible for weight loss rather than weight gain.Big over-the-counter cannabis stock magnate Cannabis Science (OOTC: CBIS) has even take a commercial interest in the prospect. But does the science in this case hold up?
Despite the evidence from everyday experience and from clinical trials that demonstrate cannabis induces appetite, the prevalence of obesity in the population which uses cannabis actually appears significantly less than nonusers from the general population.
Data analysis from two high-quality national epidemiologic surveys “assessed a significantly lower prevalence of obesity” among cannabis users compared to non-users. 
In a survey of over 30,000 people by the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), people who self-reported abstaining from cannabis had nearly twice the rate of obesity (22.0%) compared to those who reported cannabis use(14.3%).  This difference remains significant even after adjusting for confounding factors like sex, age, and even tobacco use. 
Scientifically, cannabis-induced appetite suppression may be explained by the existence of CB1-dependent feeding regulations that are known to exist in the peripheral nervous system synapsing on the digestive tract.  It found in mice that food deprivation increases intestinal endocannabinoid levels, and that feeding caused a return to normal levels.  It was further demonstrated that known CB1-receptor antagonists (inactivators) caused decreased appetite and weight loss in obese mouse models. 
Therefore, new drug discovery efforts are being mounted aimed at finding compounds which act selectively at these receptor sites,with the idea of avoiding undesirable side-effects from cannabinoid activity in the central nervous system. [1,5-6]
- Randall, PA, et al. “The novel cannabinoid CB1 antagonist AM6545 suppressesfood intake and food-reinforced behavior”. PharmacolBiochemBehav, 2010;97(1):179–84.
- Le Strat, Y, and Le Foll, B. “Obesity and cannabis use: results from 2 representativenational surveys”. Am J Epidemiol, 2011;174(8):929–33
- Santacroce, R, et al. “P.6.d.004 A possible role of cannabis and synthetic cannabimimetics as weight loss agents: preliminary indications”, European Neuropsychopharmacology,Volume 25, Supplement 2,2015, Page S613.
- Gomez, R, et al. “A peripheral mechanism for CB1 cannabinoid receptordependentmodulation of feeding”. J Neurosci. 2002;22(21):9612–7.
- Le Foll, Bernard, et al. “Cannabis and D-9-tetrahydrocannabinol (THC) for weight loss?” Medical Hypotheses, 2013,volume 80,pages 564–567.
- Alonso, M, et al. “Anti-obesity efficacy of LH-21, a cannabinoid CB(1) receptorantagonist with poor brain penetration, in diet-induced obese rats”. Br J Pharmacol. 2012;165(7):2274–91.