Kathleen Zelman: Trans Fats -- Just How Bad Are They?
Get the trans fat facts
WebMD Weight Loss Clinic - Live Events Transcript
You may have heard about these man-made fats, but what's so bad about them, and how do we avoid them? Are they one key to our growing obesity problem? We got the skinny on trans fats from WebMD Weight Loss Clinic Dietitian Kathleen M. Zelman, MPH, RD, LD
The opinions expressed herein are the guest's alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.
Moderator: Welcome to WebMD Live, Kathleen. To start, tell us what exactly trans fats are.
Zelman: Trans fats are basically vegetable fats that have been changed chemically by a process known as hydrogenation and typically they take a healthy fat, such as corn oil or soybean oil and make it solid. They're frequently found in foods that contain some kind of fat, such as:
The advantage is that the fat generally has a longer shelf life, or in the case like crackers, gives them a crisper texture. It's a product that's been used in food manufacturing for quite some time.
The problem is that the body treats the hydrogenated fat like it's a saturated fat, similar to butter or animal fat. As most of us know, saturated fat is the culprit that clogs arteries. So in essence trans fats, while initially a healthful oil that's unsaturated, becomes a saturated fat through this process of hydrogenation and is linked to causing heart disease.
Moderator: Recently, there was a change announced in labeling rules, so now trans fats will be required on food labels. What are we looking for on those labels, as far as numbers and amounts of trans fats?
Zelman: The new rule will not go in effect until Jan. 1, 2006, so manufacturers have plenty of time to phase in the new labels. Hopefully, we'll start to see these changes on the nutrition fact panel sooner than that.
Savvy consumers should look first at the total fat content at one serving of the food product. First and foremost the total amount of fat is the most critical aspect. As a nation we've been urged to lower our total amount of fat to less than 30% of total calories. That's the most important issue -- lowering our fat content. The second most important issue is that the saturated fat and the trans fatty acids be as low as possible. So it's better to choose a food that is higher in monounsaturated fat or polyunsaturated fat than saturated fat or trans fatty acids.
Moderator: How about some tips for limiting trans fats in the diet until those labels come out?
Zelman: First of all, read the nutrition labels and look at the total fat and saturated fat, and remember that the information on the nutrition label is per serving, so be sure to check the serving size. Choose reduced fat and fat-free products whenever you can. Be a sleuth for the terms "partially hydrogenated" or "hydrogenated oil" on the package ingredient list. This list is different from the nutrition facts panel. It's the list of all the ingredients in the product. It goes from the ingredients in the greatest amount to the least amount. So if a product has as its first ingredient partially hydrogenated oil, you can rest assure there will be plenty of trans fats in that product.
Member question: Why are trans fats so bad? Haven't they been around for a long time? Why are we just hearing about them now?
Zelman: There's been a decade-long debate about heart-health concerns of hydrogenated and partially hydrogenated oils, which are the principle sources of trans fats in our diet. The correlation between trans fats and heart disease has come to light thanks to the Center for Science in the Public Interest. They have been badgering Congress to make changes to help educate consumers that trans fats act like saturated fats in the body and tend to increase blood cholesterol levels. The information on food labels should help millions of consumers make healthier choices and ultimately lower their blood cholesterol levels.
Moderator: What are the top ten trans fats foods out there?
Zelman: This is the top 10 list of where you're most likely to get your trans fats: