According to Professor Daniele Piomelli, humans developed______.

Ever wonder why foods that are bad for you—such as fat-laced potato chips and French fries—taste so good? It turns out they follow the same pleasure-inducing biochemical pathways through the body as marijuana does, encouraging people to keep eating even when they know they should stop.
    There used to be an old television commercial in the United States that boasted a certain brand of potato chip tasted so good, you could never eat just one. It turns out there is a biological reason for that.
    Daniele Piomelli is a professor of farm-ecology and biological chemistry at the University of California, Irvine. He says fat is an important component of healthy human cell membranes and high-fat foods, which are rare in the wild, and were prized by early humans as a rich source of energy. As a result, Daniele Piomelli says humans developed a biological preference for fatty foods.
    Piomelli’s and colleagues have discovered a biological pathway that encouraged ancient humans to eat large quantities of the scarce nutrient whenever they found it for survival. Today, eating fat still provokes feelings of pleasure and satisfaction, similar to the high people get when smoking marijuana.
    Piomelli said when fatty foods are swallowed and hit the upper digestive tract, they trigger the production of endocannabinoids. That’s the same class of feel-good chemicals that marijuana, or cannabis, stimulates in the brain.
    Endocannabinoids in the gut send a surge of cell-signaling to the brain, which shoots back a message telling the body to keep eating.
    Piomelli and colleagues discovered the fat pathway in research with rats.