The feeling of increased appetite after using cannabis has been documented for hundreds of years. This is often called "the munchies." Unfortunately, it is only recently that any scientific research has been conducted to understand why cannabis use has this effect.
The first human study confirming that increased appetite, particularly the craving of sweet food, actually correlated with cannabis use was conducted in 1971. Other research has been conducted since that time, once again confirming that sweet snacks such as cookies, candy bars and cakes are preferable over savory snacks to cannabis users. Some research also found that after a period of time, marijuana users showed an increased body weight.
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 successfully used to control wasting in patients with HIV and cancer as well as to decrease appetite and weight in obese patients. Even though marijuana has been used in this way, little is still known about marijuana and the mechanisms at play, in terms of appetite. It is believed that with further research it is likely that the therapeutic benefits of marijuana for weight control can be even better understood and controlled.