Until about the 1600s sugar was scarce in the human experience. Because it was such a good source of quick energy, the human body was drawn to it to store as much of it as could be had, because when human's were hunter-gathers it could be a very long time before it was found again. It is natural that we are drawn to sugar. However, our systems are still geared toward ensuring we get as much as we can, while we can- but it is no longer scarce. In fact the proliferation of refined sugar beginning of the1600's as well as the eventual processing into so many forms makes sugar one of the most common ingredients in the modern food system.