It finds that fat may trigger the same mental pathways that trigger endocannabinoids, a chemical triggered by smoking the reefer. This reveals how marijuana exploits our neurochemistry. We know that fruit got a selective advantage by exploiting our taste buds by being sweet (one of our body's methods for determining nutrient and mineral density).
Taste is not enough, however, and our bodies needed to develop redundant systems for motivating us to eat saturated animal fats. Marijuana exploits a secondary system. Very cool stuff.