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Kathleen Zelman: Trans Fats -- Just How Bad Are They?

Get the trans fat facts

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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:

  • Cookies
  • Crackers
  • Fried foods (like fried chicken)
  • French fries
  • Doughnuts
  • Margarine

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.

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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:

  1. Margarine. Try to choose tub margarine, which will have the least amount of both trans and saturated fats.
  2. Packaged foods. Things like cake mixes, Bisquick, they tend to add fat into the mix. Do-it-yourself baking allows you to reduce the fat.
  3. Soups. Both dried and liquid soups can contain very high levels of trans fats. Try making your own.
  4. Fast food. Primarily I mean those foods deep-fat fried, even when some chains indicate they use liquid oil instead of partially hydrogenated oil sometimes trans fats are sprayed on products in the food manufacturing. Order grilled chicken or skip the fries.
  5. Frozen food. This included products from frozen dinners to frozen chicken, frozen breaded fish or chicken, pizzas. Check the label. Even if it says low fat, it can still have trans fat. Choose frozen food with the lowest grams of total fat.
  6. Baked goods. Donuts, cookies, cakes, frostings, all have plenty of trans fats. Make them at home or eat them less often or in smaller quantities.
  7. Candy and cookies. Lots of trans fats lurking in this area. If it contains chocolate or coconut or other high-fat items, satisfy your sweet tooth with things like hard candies or jelly beans, which don't have any fat.
  8. Chips and crackers. Go for baked if you must have your chips. Choose low-fat crackers. Think pretzels and other alternatives that have no fat.
  9. Breakfast food. From cereals to breakfast bars, trans fats can be found in this category. You need to read the label and choose cereals that have no fat and breakfast and granola bars that are low in fat.
  10. Toppings, dips, and condiments. These would be things like salad dressing, mayonnaise, gravy, whipped toppings, nondairy creamers, hot fudge. Wherever you can, try to substitute a lower-fat alternative. For example, use oil and vinegar instead of a creamy salad dressing; low-fat milk instead of nondairy creamers.

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More About Trans Fats

Member question: What about butter?

Zelman: As a comparison, butter has 7 grams of saturated fat and .3 grams of trans fat per tablespoon. Tub margarine has 1.2 grams of saturated fat and .6 grams of trans fats per tablespoon. So tub margarine is lower in total fat than butter, even though it's a tiny bit higher in trans fats.

One of the important messages to understand is to think of trans fats like you think of saturated fats, because they both work similarly in the body. What differentiates an animal saturated fat, such as butter, is that it not only is saturated, it also contains cholesterol. No vegetable product contains cholesterol, only animal products.

Member question: I don't use much, but is it better to use regular butter or tub margarine? I really don't want the trans fats. Are the "butter flavor" sprays OK to use?

Zelman: It's a personal preference. If you prefer to use less butter than tub margarine, that's fine. Likewise, using spray products, either vegetable-based or butter-based, helps limit the amount of fat used in cooking. Whenever possible, it is always a good idea to use vegetable oil instead of a solid margarine or butter.

Member comment: But a piece of toast wouldn't taste right with vegetable oil!

Zelman: True. That's why you can't substitute it at all times.

Member question: Trans fats are still present in fat-free non-dairy creamer when partially hydrogenated oil is one of the ingredients, right? Considering a choice between that and regular half-and-half, which is worse to drink for one cup of coffee a day?

Zelman: Obviously the grams of fat in half-and-half are going to be much greater than that small amount found in the fat-free half-and-half. The bottom line remains that the total amount of fat is always the most important factor. Whenever choosing between two such products, always choose the one with the least amount of fat.

Member question: My question was actually comparing non-dairy fat-free to half-and-half (not half-and-half with fat-free half-and-half). Are trans fats so bad that a small amount of trans fat is worse than a larger amount of regular fat?

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Zelman: Actually, the best option is to use skim milk. The reality is, most people don't want skim milk in their coffee, although you might want to try strong coffee with warm skim milk, it's delicious. But regarding your question, choose the lowest-fat option that you prefer.

Moderator: Meaning even the lower-fat version with trans fats is better.

Member question: Trans fats are completely man-made, then? So they are only going to be in processed foods. Is that right?

Zelman: No, that's incorrect. Animal products have small amounts of naturally occurring trans fats that act differently than man-made trans fatty acids. The correlation between trans fats and heart disease is related specifically to the trans fats from vegetable oils. The labeling law will exclude those small amounts of naturally occurring trans fats. They "act differently," which means they're not linked to heart disease

Moderator: What is the reaction of the food manufacturers to this new attention to trans fats? Are they denying trans fats are unhealthy?

Zelman: No, and I think that the bigger picture is showing us that food manufacturers are very interested in providing consumers with more healthful options, such as we've seen with the announcement from Kraft Foods and the changes in Frito-Lay snack foods; they're both making more healthful options and smaller portions in their food lines.

Member question: How long do you think it will take manufacturers to change bread and cracker recipes to trans fat-free? I can't bake bread; I need to be able to grab it at the market.

Zelman: The good news is that most bread does not contain fat. Crackers, on the other hand, do contain trans fats; even the reduced-fat brands can still have trans fats. You need to rely on the label and at this point, choosing crackers with the least amount of total fat is your best bet to limit the amount of trans fats.

Member question: A friend is starting her baby out on cereal and one of the ingredients is hydrogenated canola oil. What will this do to the baby? He's already pretty fat.

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Zelman: I would suggest looking for a cereal that does not contain partially hydrogenated fat. And they're out there. You just need to become a savvy label reader.

We are presently experiencing an epidemic of obesity in our country, affecting both kids and adults. Whatever we can do to help get kids to eat less of the kinds of foods loaded with trans fats, and encourage them to go outside and play, will stem the tide of this escalating problem.

Moderator: Before we wrap up for today, Kathleen, do you have any final comments for us?

Zelman: One final note: The American Heart Association advises that healthy Americans age 2 and over limit the fat in their diets. In practical terms, if you limit your intake of fats and oils to five to eight teaspoons per day the American Hearth Association indicates that you're not likely to get an excess of trans fats in your diets.

Moderator: We are out of time. Thanks to Kathleen Zelman for sharing her nutrition knowledge with us today. And thank you members for joining in the discussion.

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