Rating the Cooking Fats

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Choose the healthiest (and tastiest) oils, spreads, and shortenings

By Elaine Magee, MPH, RD
WebMD Weight Loss Clinic - Expert Column

There are so many types of cooking fats and spreads to choose from at the grocery store, and so many questions to consider: Are the new margarines truly better than butter? Which oil is best to cook with in high heat? Does olive oil reign supreme?

So what's a health-conscious consumer to do? Well, because there are so many nutrient issues to consider, there is no simple answer.

Olive oil is highest in healthful monounsaturated fats, but it has few healthy omega-3 fatty acids. You can't use it for high-temperature frying, and it may impart an olive flavor when you bake with it.

Then there's canola oil, which is lowest in saturated fat and has an impressive amount of monounsaturated fat (though not as much as olive oil) as well as more omega-3s than any other vegetable oil. You can use it for both baking and high-temperature frying.

For certain bakery recipes in which you whip sugar with fat to create the proper texture (cakes, cookies, frosting, etc.), you can't substitute an oil. What's your best bet then? In these situations, I like to use margarines that are fairly low in saturated fat and fairly high in monounsaturated fat.

And where does that leave butter? Butter is very high in saturated fat (though not as high as palm kernel and coconut oils), but contains zero trans fats. It also has some monounsaturated fat (but not as much as some of the vegetable oils). I've got to admit there are certain recipes that just don't taste right without butter. So I use it in those recipes -- but the smallest amount I can get away with. And when I can substitute canola oil, olive oil, or a no-trans-fat margarine, you bet I do.

Let's start with a rundown of the different types of fatty acids, then we'll rate the cooking and table fats to help you decide which ones to buy.

Types of Fatty Acids

Saturated fats are usually solid at room temperature (like butter or lard) while others are suspended in liquid, such as with whole milk or cream.

• What they do in your body: Saturated fat can raise levels of "bad" LDL cholesterol and total cholesterol, increasing the risk of heart disease and stroke. It may also increase the risk of certain cancers.
• Bottom line: Minimize these fatty acids! The National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults recommends that less than 7% of our total calories come from saturated fat. This means a person eating 2,000 calories daily should have no more than 16 grams of saturated fat per day.

Trans fatty acids (or trans fats) occur naturally in small amounts in meat and dairy products. But most of the trans fats in our diets come from partially hydrogenated vegetable oils, found in baked goods and other processed foods. This manufacturing process transforms some of the vegetable oil's unsaturated fat into trans fatty acids, which makes them more solid and stable. You'll find trans fats in any cooking or table fat that contains partially hydrogenated fat or oils.

• What they do in your body: Their effects are like those of saturated fats, except that they offer a double whammy. In addition to raising "bad" cholesterol levels like saturated fat, trans fats also decrease your "good" (HDL) cholesterol. This is one reason many researchers consider trans fats a bigger bad boy than saturated fat. Many suspect that that trans fats increase not only the risk of heart disease, but also of type 2 diabetes, colon cancer, and, in women, breast cancer.
• Bottom line: Get as little of trans fats as possible. Some margarines and shortenings contain 20% to 40% trans fatty acids. But there is a new generation of margarines being produced that have little or no trans fats.

Monounsaturated fats stay liquid at room temperature. Many experts urge us to make oils high in monounsaturated fat our first choice for cooking.

• What they do in your body: Especially if they replace saturated or trans fats in the diet, monounsaturated fats reduce "bad" cholesterol and reduce the risk of heart disease. They may also increase "good" cholesterol, reduce blood pressure, and improve insulin sensitivity (when you also eat fewer carbohydrates).
• Bottom line: They are the smart fats! Choose cooking and table fats that contain more of these fatty acids and fewer saturated and trans fats. Aim to get 10% to 15% of your total calories from these fats. (With a 2,000-calorie-a-day diet, 15% of calories computes to 33 grams of monounsaturated fat per day.)
• Where to get them: They're found in olive oil (78% monounsaturated fat and 14% saturated fat), canola oil (62% monounsaturated fat and 6% saturated fat), peanut oil (48% monounsaturated fat), hazelnut oil (82% monounsaturated fat), almond oil (73% monounsaturated fat), avocados, and some nuts, such as almonds.