They called it Formula 47, after the total cost in cents of a burger, fries, and shake, circa 1960. Formula 47 was a blend of rendered beef fat and vegetable oil, which, when used to fry shoestring slices of Russet Burbank potatoes, imparted a flavor so rich and appetizing that it helped the restaurant selling the fries to become the world's dominant fast-food chain: McDonald's.
But that story turned into a cautionary tale whose lessons extend into every man's kitchen.
Health advocates blamed Formula 47 fries for raising customers' cholesterol, so the Golden Arches switched to what people assumed was healthier—100 percent vegetable oil.
The new oils were good fats that had been altered—hydrogenated—for flavor retention and longer shelf life. But that made them even more damaging to cardiovascular health than the saturated fats had been thought to be.
Some public-health experts now blame the trans fats in hydrogenated oils for tens of thousands of premature deaths. (Check out 18 supermarket lies to protect yourself from other harmful food additives.) According to a recent study review by the Harvard School of Public Health, trans fat may increase your risk of a host of chronic diseases and also promote weight gain. So McDonald's and others have once again reformulated their frying medium, using vegetable oil-blends that are free of trans fats.
In short, oils aren't as simple as they seem. Like McDonald's, if you cook with the wrong oil, you may be sabotaging your health. To protect your body, ease your mind, and please your palate, follow these rules.
Rule 1: Don't Rely on Vegetable Oil
Corn, soybean, and other vegetable oils have high levels of omega-6s. These polyunsaturated fats aren't bad when they're balanced with plenty of omega-3 fatty acids, like the ones found in fish. (Learn more about omega-3s and why you're likely not consuming enough of them.) But that often isn't the case in the typical American diet. "We now consume 20 to 1 omega-6s to omega-3s," says Jonny Bowden, Ph.D., author of The 150 Healthiest Foods on Earth. "Our inflammatory factory is overstaffed, and our anti-inflammatory factory is understaffed."
A high intake of omega-6 fats relative to omega-3 fats increases inflammation, which may increase your risk of heart disease, diabetes, and cancer, according to a 2008 review of studies by the Center for Genetics, Nutrition and Health. There are plenty of other choices.
Rule 2: Expand your tastes
Not all fats are created equal. Experts say the most nutritious way to go is with a few different cooking oils to help balance your intake of omega-3 and omega-6 polyunsaturated fats, as well as saturated and monounsaturated fats. "That's what most of the world has done. Old Mediterranean cultures had olive oil on salad, fish at night, and then cow or goat butter or cheese, and they were more or less accidentally coming up with the one-to-one-to-one ratio," says K.C. Hayes, Ph.D., a fats researcher at Brandeis University, in Massachusetts.
Here's an easy way to balance your diet: Match fats to the cuisine you're cooking. Making homemade spaghetti sauce? Use a drizzle of olive oil to saute the onions. Try coconut or peanut oil when you're whipping up an Asian stir-fry. Start a French-style omelet by melting a pat of butter. The greater the variety of nonhydrogenated fats you incorporate into your diet, the better. A moderate intake of all types of nonhydrogenated fat is best, according to the American Heart Association.
Wait, did we just say butter?
Rule 3: It's Okay to Use Butter
Here's great news. "The health scare surrounding saturated fat and cholesterol was overblown," says Walter Willett, M.D., chairman of the department of nutrition at Harvard University. A 2010 review of 21 studies, published in the American Journal of Clinical Nutrition, found no conclusive evidence that dietary saturated fat is associated with an increased risk of coronary heart disease, stroke, or cardiovascular disease. According to a review in the European Journal of Nutrition, a diet high in fat from dairy products like butter may raise levels of large LDL cholesterol, which is considered relatively harmless, while having no effect on levels of potentially harmful small LDL cholesterol.
Margarine, the once-sainted substitute, usually contains at least 80 percent vegetable oil, and that oil often contains trans fat. Butter also has trace amounts of naturally occurring trans fats, but not enough to cause concern. The point is that you can use butter; just don't go overboard, a caution that applies to any fat. Try whipped butter on your toast—you'll take in about a third less calories. Butter is known to be an excellent source of conjugated linoleic acid, which may be a cancer-fighting nutrient, according to Ohio State scientists. (Discover seven more fatty foods that are actually good for you.)
That doesn't mean you want to kick traditionally healthy oils, like canola oil and olive oil, out of your kitchen. Just know that butter and other nonhydrogenated natural fats are not as bad as nutritionists once thought them to be. But there's one caveat.
Rule 4: Go Easy In The Kitchen
Oils typically contain 100 to 125 calories per tablespoon—all of them from fat—so use sparingly. Cook smart. Usually 1 tablespoon of any oil is enough to coat the pan you're using. Any more is overkill.
At the supermarket, limiting dangerous fats is easy: Check labels to find products without partially or fully hydrogenated oils or trans fats—and use this list of the 125 best foods at the grocery store. At restaurants, it's a little harder. Only California has a statewide ban on serving trans fat in restaurants. (Nice, Arnold!) For a list of pending and enacted trans fat legislation in your state, go to ncsl.org and search "trans fat and menu labeling." Most fast-food chains are banning trans fats on their own, but without legislation, your primary defense is asking your restaurant kitchen directly. Or even better, use our chart (below) to cook healthier, tastier meals at home.
Which fat is best? Favor the left side of this chart; use those on the right sparingly.
*The label "vegetable oil" can mean many things. It usually refers to soybean or corn oil, or a blend that may also include sunflower or canola oil. None of these blends is preferable to canola oil, developed in Canada from a hybrid of the rapeseed plant.