What Are Fats And Why Is It Important To Know How Much Fat There Is In Certain Foods?

Howard Eisenson, M.D., Executive Director, Duke Diet and Fitness Center

February 1, 2009

Question: What are fats and why is it important to know how much fat there is in certain foods?

Answer: Fats are essential to normal health to normal growth and development. In laboratory animals that have been reared without fat, they don't survive for long. We need fat, it's a good energy source, it's a form of stored energy, it's an insulator for our tissues, it's a cushion for our vital organs. So we need to have fat and it's an important constituent of our diet.

Fats come from a whole host of sources, animal and plant. It's important for us to try to limit those kinds of fats that have been shown to have adverse effects on our health, primarily on our vascular system -- on our circulation.

We should all be concerned about anything that increases the risk for developing hardening of the arteries or atherosclerosis -- the buildup of plaque within our arteries. And certain kinds of fats are more likely to do that, notably saturated fats, which we find in meat and dairy products. And also trans fats which are primarily artificially produced as a way to extend shelf life of fat containing products. We see that in baked goods, in French fries and other kinds of products that have been altered artificially.

On the other hand, a healthier source of fats would be the so-called polyunsaturated or monounsaturated fats. And this has to do with the chemical structure of the fat molecule. If the maximum amount of hydrogen has been added, is part of a molecule, we call that a saturated fat. If there are some chemical bonds that are not fully saturated with hydrogen we call those monounsaturated or polyunsaturated fats.

So all kinds of fats play a role in health. All kinds of fats are ok. We want particularly to limit the saturated fats and the trans fats and have most of the fat in our diet come from polyunsaturated and monounsaturated sources.

Copyright © 2009 ABC News Internet Ventures