The color blue suppresses appetite more than any other color. Apart from blueberries and plums, which are mostly purple, there are few naturally blue foods. The hypothesis is that in the remote past, when humans foraged for food, blue was a warning of spoilage or danger.
The Buffet Blues by National Geographic: Everyone loves an all you can eat buffet, but controlling our appetites can be a bit of a struggle. We’re testing to see if a simple change of scenery can impact peoples’ portion sizes.