New facts on fats
Here’s a quick quiz on fats and health. Answer the following questions with yes or no as honestly as you can:
• Does your kitchen contain a lot of olive oil as you believe it to be the healthiest choice for cooking?
• When scrutinizing a product’s Nutrition Facts label, do you check the fat content first before the calories?
• Do you turn up your nose at corn oil, thinking of it as only a notch or two healthier than lard?
If you answered “yes” to these questions, then your knowledge of fats needs updating. It’s true that in the early 1990s, nutrition science suffered from what some have called “fat phobia,” thinking that reducing dietary fat any type of fat was a key to healthy living. But by 2000, that fixation on total fat was replaced with an emphasis on the pros and cons of specific types of fat.
“It’s a lot more nuanced now, focused on quality rather than quantity,” says Alice H. Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tuft University’s Jean Mayer USDA Human Nutrition Research Center on Aging in Boston. Targeting total fat, she adds, had unintended consequences for consumers: Instead of eating more fruits, vegetables, and legumes, people went for low-fat brownies, low-fat ice cream, and low-fat cookies. The net result was in contrast to what was intended: Total calorie intake did not go down and at times, the types of fat that should have been restricted saturated and trans fat did not go down as well.”
Often those “low-fat” alternatives were just as high in calories as the originals, causing consumers to pack on pounds while eating “guilt-free” “low-fat” goodies. And calories need to be front and center in the battle for healthy eating, as the current obesity epidemic makes clear. Indeed, the chief reason to keep the total fat content of your diet under control turns out to be that fats are a highly concentrated form of calories. All fats, regardless of type, pack nine calories per gram (compared to four in protein or carbohydrates) that’s about 120 calories per tablespoon.
At one time, it was also thought that total fat intake might be associated with risk for some cancers. In 2006, however, the Women’s Health Initiative failed to find any benefits from a low-fat diet in reducing the risk of breast or colon cancer. Today, the American Cancer Society says, “There is little evidence that the total amount of fat a person eats affects cancer risk.” Instead, Michael Thun, MD, emeritus vice president of epidemiology for the society, says there’s more evidence that cancer risk increases with you guessed it being overweight or obese.
Your body actually needs some fats. The American Heart Association (AHA) recommends consuming no more that 25 percent to 35 percent of your total calories from fats.
Better than olive oil
Buying only olive oil, known to be high in monounsaturated fats, dates you to the early 2000s. Aggressive promotion by olive-oil makers, who saw sales jump by almost a third from 1997 to 2003, culminated in an official blessing by the US Food and Drug Association (FDA). In 2004, the FDA approved a “qualified health claim” for olive oil as a heart-healthy substitute for saturated fats such as butter.
Nutrition experts today still think olive oil is better for you than saturated fats but balk at the notion that it’s better than other vegetable oils. “If you’re substituting olive oil for butter, that’s good,” says Lichtenstein. It has the same number of calories. It doesn’t really matter whether you use soybean, canola, sunflower, safflower or corn oil, or a mixture. Use the oil that is best for the specific purpose you need it for. If you consume more calories, you have to exercise more. That is the bottom line.
In fact, a new study confirms that polyunsaturated fats found in greater percentages in soybean, sunflower, safflower and, yes, corn oil are effective substitutes in fighting heart disease. Polyunsaturated fats may even be better for you than the monounsaturated kind that elevated olive oil to nutritional stardom.
Marianne V. Jakobsen, of Aarhus University Hospital in Denmark, and colleagues reviewed 11 studies totaling more than 340,000 participants, publishing their findings in the American Journal of Clinical Nutrition. Their conclusion was clear: “The associations found in this study suggest that saturated fatty acids should be reduced and replaced with polyunsaturated fatty acids to prevent coronary heart disease among all middle-aged and older women and men.” Data showed that switching from saturated fat to polyunsaturated fat for five percent of calories was associated with a 13-percent reduced risk of coronary events and 26-percent less risk of coronary deaths even after adjusting for other lifestyle factors.
“This shouldn’t come as a surprise,” says Lichtenstein, noting that the findings match research done in the 1960s as well as recommendations by the AHA dating to 40 years ago. “The key is substituting and in some cases cutting down total calories wisely.”
Among commonly purchased oils high in polyunsaturated fats, she adds, the most cost-effective choice is soybean oil. (Though don’t be fooled by partially hydrogenated soybean oil, which contains unhealthy trans fats.) Sunflower, safflower, and corn oil are also good choices. For a commonly purchased oil high in monounsaturated fats, a cost-effective choice is canola oil, which falls in between these and olive oil in the ratio of poly- to monounsaturated fat (see chart).
Basic fats 101
If you’re confused by all this talk of mono- and poly- and saturation and we haven’t even gotten to the infamous trans fats here’s a simple rule to remember: Choose oils that are liquid at room temperature (with the exception of tropical oils palm, palm kernel, and coconut). That includes both monounsaturated and polyunsaturated fats. Cut out saturated fats (think of butter and the fat you trim off a steak) and trans fats, which have been processed to stay solid.
Cooking oils are made up of a mix of fatty acids, which we short-hand to fats; olive oil is mostly oleic acid, for example, while safflower is rich in linoleic acid. These various fatty acids make up the Total Fat content of packaged goods and are found in foods ranging from meat to nuts to avocados.
Saturated fats typically come from animal sources, such as meats and butter or other dairy products, but are also found in some tropical plants, including palm oil, palm kernel oil, and coconut oil. Many baked goods and fried foods contain high amounts of saturated fats. The primary dietary culprit in raising blood levels of LDL (“bad”) cholesterol, saturated fats increase your risk for heart disease. The American Heart Association recommends limiting saturated-fat intake to less than seven percent of total daily calories; for a 2,000-calorie daily diet, that’s a maximum of 140 calories from saturated fat, or about 16 grams a day. That’s a bit more than found in two tablespoons of butter. You can calculate your own daily fat limits with the association’s online My Fats Translator at www.americanheart.org/myfatstranslator.
When used to replace saturated fats, monounsaturated fats can help reduce LDL cholesterol levels. Despite the recent findings by Jakobsen and colleagues, most experts think switching to monounsaturated fats can reduce your risk for heart disease and stroke.
However, polyunsaturated fats may be the best substitute for saturated fats to lower LDL cholesterol and fight heart disease. Polyunsaturated fats also include the omega-3 and omega-6 fatty acids. Omega-3s, found in fish, have been linked to a wide range of health benefits. Omega-6s are more controversial, and some studies suggest they may have inflammatory effects.
Unsaturated fats are converted to trans fats through an industrial process that adds hydrogen (hence the term “hydrogenated”) to make them solid at room temperature and more convenient for commercial use. A dietary double whammy, trans fats both raise LDL (“bad”) cholesterol and lower HDL (“good”) cholesterol. The AHA advises limiting trans fat intake to less than one percent of total daily calories two grams a day on a 2,000-calorie diet.
Now, you should be up-to-date and ready for your next quiz or making smart decisions at the supermarket and in the kitchen. Remember: Worry about calories more than total fat (keeping in mind that all fats are high in calories). Add polyunsaturated fats to your shopping cart and substitute healthy fats for saturated fats.
To learn more: American Journal of Clinical Nutrition, May 2009; abstract at www.ajcn.org/cgi/content/abstract/89/5/1425.
