Figuring out Fats
Interview with Dr. Bruce Fife
Interviewed by Raena Morgan
January 20, 2009
Raena Morgan: Bruce, there is several fats: monounsaturated, polyunsaturated, saturated fats. Could you explain the difference between them?
Dr. Bruce Fife: Basically, a saturated fat is a chain of carbon atoms that have hydrogen—2 hydrogens—attached to each carbon.
BF: And it holds as many hydrogens as that molecule can. A monounsaturated fat is missing two of the hydrogens. So, one carbon—mono—is missing two hydrogens. In a polyunsaturated fat, there are two or more carbons missing their pair of hydrogens. And so, that’s the definition of the polyunsaturated, the monounsaturated and saturated fats.
RM: How does that play out in different oils that we go to the supermarket to buy, for example?
BF: Well, it’s kind of interesting because people often get the tendency to believe that a polyunsaturated oil, such as corn oil, is 100% polyunsaturated. But no oil is 100%. All oils are a mixture of all three. So, soybean oil, for example, is predominantly polyunsaturated, but it also has monounsaturated and saturated fats in it. The same with olive oil.
RM: That’s right.
BF: We think of that as a monounsaturated, but it also has polyunsaturated and saturated fats. And the same goes with lard. Lard is predominantly a saturated fat, but it also has a high concentration of monounsaturated fat and polyunsaturated fat. So, all the fats in our diet are actually a mixture of these. And we refer to them loosely as either saturated, monounsaturated or polyunsaturated.