Getting to the Heart of a Healthful Diet: Fats
Fats are a vital part of a balanced diet. This nutrient helps to protect the nerves and provide energy. However, a diet high in fat can also contribute to obesity and heart disease. The types of fats are also important to consider.
The fats we eat effect the amount and type of cholesterol in our blood. There are too major types of cholesterol in the body, LDL and HDL. High levels of LDLs, (known as bad cholesterol) is a major risk factor for coronary heart disease, which leads to ]]>heart attack]]> . However, high levels of HDLs (known as good cholesterol) reduce the risk of coronary heart disease.
Saturated fats and trans fats raise LDL levels. Dietary cholesterol can also increase LDL levels but does so at a much lesser degree than saturated and trans fat. Since saturated fat and cholesterol are often found together in foods, limiting saturated fat, will also make cholesterol intake will go down as well.
On the other hand, unsaturated fats may help lower LDL levels when used in place of saturated fats in your diet.
Keep in mind that fat contains more than twice the calories of either protein or carbohydrate. One gram of fat contains nine calories, while one gram of protein or carbohydrate provides four calories. With any type of fat be careful how much you consume.
Foods often have more than one type of fat. As a general rule, those that have mostly saturated fat are from animal products (except some oils), while those that are unsaturated are from plant sources.
Foods rich in saturated fat include:
- Whole milk
- Ice cream
- Whole-milk cheeses
- Palm and palm kernel oil
- Coconut oil
- Cocoa butter
Many snack foods and fried foods are also rich in saturated fat. Check the Nutrition Facts label to find the saturated fat content of a specific food.
Foods that are naturally rich in saturated fat may have low-fat versions. Some are more tasty than others, so try a variety of them to find ones you like. Use these lower-fat versions, or use the original versions very infrequently. Also, try to choose naturally lower-fat foods. For example, have fruit and gingersnaps for dessert instead of ice cream. And eat fish and vegetarian-based dinners several times a week in place of meat.
Trans fats are made through the process of hydrogenation. This process takes a vegetable oil, which is naturally high in unsaturated fatty acids, and adds hydrogen molecules to it to make it more saturated and more solid. Depending on how many hydrogens are added, the result of this process can be a hydrogenated oil or a solid margarine. These products do not contain cholesterol, as butter does. (Any food that comes from a plant does not contain cholesterol.)
Hydrogenated oils are used to make many processed snack foods.
Foods rich in trans fat include:
- French fries
- Fried onion rings
Trans fats are also required to be listed on the Nutrition Facts food label. This fat should be less than one percent of your daily calories. For a 2000 calorie diet this means no more than 20 calories or 2 grams.
Trans fats significantly increase the risk of heart disease (much more than saturated fats) by raising low-density lipoprotein (LDL) cholesterol levels (so called bad cholesterol) and lowering high-density lipoprotein (HDL) cholesterol levels (good cholesterol). They also increase your body’s propensity to form blood clots, which again increases the risk for coronary events. There are no safe limits in terms of consumption of fatty acids. In many cities restaurants have been required to remove trans fats from their cooking process.
You can feel good about eating this type of fat! But unsaturated fats still deliver as many calories as the saturated varieties, so don't go overboard.
Foods rich in polyunsaturated fats include:
Omega-3 Fatty Acids (a type of polyunsaturated) found in:
- Fish and fish oils
- Nuts (eg walnuts)
- Oils (eg, soy and canola)
Foods rich in monounsaturated fats include:
It's easy to work these foods into your diet:
- Combine nuts, seeds, dry cereal, and dried fruit for a snack mix.
- Use mashed avocado as a sandwich or bagel spread.
- In sesame oil, sauté vegetables, tofu, and peanuts.
- Bake pecans or walnuts into breads, pancakes, and muffins.
- Use an oil sprayer for your cooking oils; spray meats and vegetables and sprinkle with herbs before cooking.
- Coat salmon or tuna steaks in sesame oil and sesame seeds before broiling.
Butter vs. Margarine
Since both the saturated fat in butter and the trans fat in margarine can raise blood cholesterol levels, which is the best one to eat? There is no definitive answer to this question. When choosing your spread, consider the following:
The softer the better:
- Whipped butter has less saturated fat than stick butter
- Liquid and soft tub margarine contain little saturated fat or trans fat
- Whichever you choose, limit the amount you use
- When cooking and baking, substitute an unsaturated oil (see below) for butter or margarine
Many higher fat products such as butter, margarine, and mayonnaise now contain mixtures with higher amounts of unsaturated fats with little or no trans fats. Many also now include Omega-3s. Read the nutritional facts label to find options best for you.
Remember even though the product may contain healthier fats, they still need to be used in moderation!
American Heart Association
International Food Information Council
Dietitians of Canada
Heart and Stroke Foundation of Canada
Erkkila A, de Mello VD, Riserus U, Laaksonen DE: Dietary fatty acids and cardiovascular disease: an epidemiological approach. Prog Lipid Res. 2008;47:172-87
Booker CS, Mann JI: Trans fatty acids and cardiovascular health: translation of the evidence base. Nutr Metab Cardiovasc Dis. 2008;18:448-56.
Information on trans fat. US Food and Drug Admisnitration. Available at: http://www.fda.gov/oc/initiatives/transfat/ . Accessed January 17, 2007.
Mensink RPM, Katan MB. Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. N Engl J Med. 1990;323:439-445
Wahrburg U. What are the health effects of fats? Eur J Nutr. 2004;43(suppl 1):1/6-1/11.
Last reviewed January 2009 by ]]>David Juan, MD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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