What are “the munchies”?

The feeling of increased appetite after using cannabis has been documented for hundreds of years. This is often called “the munchies.” It is only recently that any scientific research has been conducted to understand why cannabis use has this effect.

The first human studies confirming that increased appetite, particularly the craving of sweet food, actually correlated with cannabis use were conducted in the early 1970s.  Research conducted since has confirmed that marijuana increases both the desire to eat and the palatability of food (Kirkham TC, 2009).

Is there potential for marijuana to be used for weight control?

The therapeutic uses of cannabinoids have been investigated following observed increases in appetite and body weight in a number of human studies. Subsequently, marijuana (both illicit and synthetic preparations) has been used successfully to control wasting syndrome in patients with AIDS and cancer. The role of cannabis and endocannabinoids in appetite regulation has been extensively studied, but the association of cannabis use with weight in the general population is less known.

A 2009 study examining the prevalence of obesity as a function of cannabis use, however, found lower rates of obesity among regular cannabis users (at least 3 days a week) than the general population (Le Strat & Le Foll, 2011). A recent study in the American Journal of Medicine also found that current marijuana use was associated with 16% lower fasting insulin levels and smaller waist circumferences, which may make it a useful tool in treating diabetes and obesity (Penner et al, 2013). Even though a correlation between marijuana use and weight loss or maintenance is increasingly being documented, little is still known about the mechanisms at play. With further research it is likely that the therapeutic benefits of marijuana for weight control can be better understood and controlled.

How does using marijuana affect appetite?

Recently, researchers have been able to get a better understanding of how marijuana alters appetite by studying animals and the actual chemical pathways involved within our body.

There are over 480 natural components found within the cannabis sativa plant, of which 66 have been classified as “cannabinoids” – chemicals unique to the plant. The most well-known and researched of these, delta-9-tetrahydrocannabinol (Δ9-THC), is the substance primarily responsible for the psychoactive effects of cannabis.

Like opiates (substances derived from the opium poppy such as heroin), cannabinoids affect the user by interacting with specific receptors, located within different parts of the central nervous system. Today it is known that we have receptors that respond to cannabis as well as cannabinoid- like substances that exist inside us (“endogenous cannabinoids”). The particular receptor most often associated with cannabis use and appetite regulation is known as CB1. To date, the CB1 receptor has been found to be active in several areas of the body known to stimulate eating behavior, including the following:

  • The sections of the hypothalamus and hind brain that regulate food intake;
  • The reward centre of the brain – helping food make us feel better;
  • From within stomach and intestinal tissue – helping us know when we are hungry;
  • The limbic forebrain – helping food seem more palatable.

Put simply, when someone uses cannabis, they are replicating an effect the body produces for itself, only much more intensely – thereby changing eating behavior (Cota D et al., 2003).

References

  • Cota D, Marsicano G, Lutz B, et al.  Endogenous cannabinoid system as a modulator of food intake. Int J Obes Relat Metab Disord 2003;27(3):289-301.
  • Kirkham TC.  Cannabinoids and appetite: Food craving and food pleasure. Int Rev Psychiatry 2009;21(2):163-171.
  • Le Foll B, Trigo JM, Sharkey KA, Le Strat Y. Cannabis and Δ9-tetrahydrocannabinol (THC) for weight loss? Med Hypotheses 2013;80(5):564-7. View abstract
  • Le Strat Y, Le Foll B.  Obesity and cannabis use: Results from 2 representative national surveys.  Am J Epidemiol 2011;174(8):929-933.   View abstract 
  • Marijuana users have better blood sugar control.  Science Daily, May 15, 2013.  Free online
  • Penner EA, Buettner H, Mittleman MA.  The impact of marijuana use on glucose, insulin, and insulin resistance among US adults.  Am J Med 2013 126(7):583-589.  View abstract
  • Szalavitz M.  Marijuana: The next diabetes drug?  Time Magazine, May 21, 2013. Free online
  • Szalavitz M.  Marijuana slims? Why pot smokers are less obese.  Time Magazine, Sept 8, 2011. Free online

Updated 2013. This information adapted with permission from the National Cannabis Prevention and Information Centre in Australia.