The Facts on Fats

If “fat” has become a dirty word in your nutritional arsenal, you should know that all fats are not the same. Some may be harmful, but others are helpful—even necessary—for proper functioning of our bodies.

The key is choosing the right fats. Since January, the Food and Drug Administration has required manufactured food labels to break down the kinds of fats and include the amount of trans fat as well as saturated fat.

Who needs fat? Everyone. Both animal and plant-derived food products contain fat, which is a prime source of calories for energy. Fat provides essential fatty acids not produced by our bodies, regulates cholesterol metabolism and other processes, and promotes proper growth and development, explains Cindy Moore, director of nutritional therapy at the Cleveland Clinic Foundation. Fats also transport fat-soluble vitamins A, D, E, and K—important for vision, healthy skin, and proper immune function—to cells and aid their absorption in the intestines.

As a food ingredient, fat enhances taste, aroma and texture. Because dietary fat increases satiety, people may actually eat less and lose weight when fats are included (in moderation) as part of a diet plan, says Moore.

The Institute of Medicine’s 2005 guidelines recommend that 20 to 35 percent of the total daily calorie allotment for adults come from fat. Keep in mind that all fats contain the same number of calories (100 per tablespoon), regardless of saturation.

The Good, the Bad and the Yucky

Good fats: Unsaturated oils appear to increase cell fluidity and flexibility, thus contributing to overall health, says Moore. Chemically, these may be monounsaturated or polyunsaturated (a technical measure of how many hydrogen atoms their molecules can link to), both of which seem to lower blood cholesterol when substituted for saturated fats. Heart-healthy monounsaturated fats—oils like olive and canola—stay liquid at room temperature but become cloudy or solidify if put in the refrigerator. Avocados and most nuts (including spreads like peanut butter) contain monounsaturated fats, as well as many other essential nutrients, therefore making them healthy additions to your diet.

Polyunsaturated fats are liquid at room temperature as well as when refrigerated and include common vegetable oils such as corn, soy, sunflower and safflower. Most liquid oils contain some of all types of fats, but the proportion is what counts. Peanut oil is on the lower end of the unsaturated spectrum, but it is easily utilized by the body and can be totally hydrogenated, leaving no unhealthy trans fats, according to Moore.

Dieticians urge us to include more omega-3, a polyunsaturated fat, in our diets. Research indicates that it may have an anti-inflammatory effect, important in reducing risk of heart disease. Barry Swanson, professor of food science and nutrition at Washington State University, says omega-3s appear to protect the heart by making blood platelets less likely to clot. Recent studies have also reported a possible protective effect for eye diseases. Foods rich in omega-3 fatty acids include fish like tuna, salmon, mackerel and herring, plus flax seeds or oil, and walnuts.

Omega-6 is also beneficial—to a point. Researchers in England found that supplements of omega-3 and omega-6 oils helped improve the behavior and language skills of rowdy kids. However, because many commercially prepared foods contain soybeans and oils high in omega-6, our diets tend to include more than we need, which can promote inflammation.

Bad and yucky fats: Saturated fats and trans fats are sometimes lumped together as “bad” components of food because they can clog arteries and raise levels of LDL (“bad” cholesterol). Health authorities recommend that these fats not exceed 10 percent of a person’s calories (22 grams for a 2,000 calorie diet) if their LDL is less than 130. If LDL is greater than 130, authorities often suggest keeping daily saturated fat consumption under 15 grams. Given that a single cookie may contain four or five grams of fat, reading labels is essential, says Katherine Tallmadge, a Washington, D.C.-based spokesperson for the American Dietetic Association.

Additionally, saturated fat intake has been linked to diabetes and depression. Animal products like butter, lard, whole milk and meat are high in saturated fats, which are solid and waxy at room temperature.

Trans fats have similar effects as saturated fats, with an added negative at high levels because they not only raise LDL levels, but they also reduce HDL (the good cholesterol). Trans fats began showing up in high amounts about 20 years ago in many foods after commercial processors began using polyunsaturated fats (considered healthy) in a wide range of baked goods and snacks.

The problem was that the process used, partial hydrogenation—which transforms oils into solids, thereby giving foods crisp and flaky properties, taste stability and increased shelf life—also created trans fats that clog arteries, increase risk of heart disease, and contribute to obesity. A safe amount hasn’t been identified, so most health authorities recommend eating as little as possible. Although mostly manmade, trace amounts of trans fats occur naturally in some meats and dairy products.

Sandy Procter, a Kansas State University nutrition specialist, says that consumers should also be on the lookout for the words “partially hydrogenated,” which indicate trans fat content. In addition, the FDA now requires the direct labeling of trans fats on U.S. food packaging.

Eating Smart

Swanson recommends consuming fruits and vegetables along with fats to help the body handle fats better. Tallmadge adds: “There is a theory that the ratio of polyunsaturated fat to saturated fat in the diet may be more influential in heart disease risk than the absolute number.”

Favorite fat foods: Some foods contain a natural mix of saturated fat together with healthy nutrients. Tallmadge explains: “Chocolate contains antioxidants and anti-platelet factors. Coconut contains polyphenols and antioxidants. Some evidence suggests these benefits may outweigh risks, but most experts still don’t recommend eating large amounts of these foods.”

What about environmental toxins? Environmental hydrophobic toxins such as polychlorinated biphenyls (PCBs) and dioxin, both determined to be carcinogenic by the Environmental Protection Agency, can concentrate in animal fat, fatty skin of cold-water fish and dairy products. “The trace amounts of environmental toxins in fat-containing foods do not pose a great hazard or risk for carcinogenicity,” says Moore. However, many experts suggest, to be safe, people may want to choose lower fat or organic products.

Control fat consumption by shopping the perimeter of the grocery store—and not when you’re hungry, or you’re likely to purchase more convenience foods containing unhealthy fats, says M

oore. Choose lean meats (trim visible fat), low-fat or skim dairy products, nuts for snacks, and soft “margarine-like” spreads made with healthy oils. Moore suggests replacing fat calories with fresh produce and cooking more from scratch.

BEVERLY BURMEIER is a Texas-based freelance reporter.