On the left, olive oil, which is low in saturated fat and high in monounsaturated fat, which may lower bad cholesterol levels. On the right, coconut oil, which is 90 percent saturated fat and may raise bad cholesterol levels. iStockphoto hide caption

itoggle caption iStockphoto

A slice of pork belly, with a thick layer of fat. "If we confirm that fat is a basic taste quality, it's the equivalent of saying chartreuse is a primary color," Richard Mattes of Purdue University says. "It changes our basic understanding of what taste is." Xiao He/Flickr hide caption

itoggle caption Xiao He/Flickr

Nutrition researchers are reaching a new consensus: Cut back on all those refined carbs. And remember that some fat is good. Stacy Spensley/Flickr hide caption

itoggle caption Stacy Spensley/Flickr

The 1990s were rife with low-fat packaged snacks, from potato chips to cookies. Youtube and RetroJunk hide caption

itoggle caption Youtube and RetroJunk