Warm colors, such as red and orange, are believed to cause people to feel hungry. Many fast food restaurants, such as McDonald's, Wendy's and Burger King, use these colors in their logo. Cool colors, such as blue and purple, are thought to suppress hunger.
According to the Psychology of Color, colors such as red, orange and yellow induce hunger, happiness and excitement in people. These colors are often recommended for places where people gather to eat, such as the kitchen and dining room. Colors such as green, blue and purple are believed to make people feel peaceful and tranquil. Cooler colors can also suppress appetite, possibly because these colors are associated with food that has spoiled.