Of all our cultural myths and misunderstandings, food fallacies seem to run especially rampant. We absorb "guidance" from our families ("Eat your margarine"), fad-diet books ("Bread is the root of all evil"), the nightly news ("Milk saves the world!"), and that beacon of frequently off-the-wall information, the Internet. "People are extremely confused about what to eat," acknowledges New York-based physician Jana Klauer, M.D., author of "How the Rich Get Thin". She and other prominent nutrition experts helped us set the record straight, exposing seven myths you might have heard -- but shouldn't believe.

Myth: A calorie is a calorie.
In fact, our bodies can distinguish one type of calorie from another. "We handle fat calories, carb calories, and protein calories differently," says Andrew Weil, M.D., author of "Eating Well for Optimal Health." "Some tend to be stored as fat; some tend to be digested more quickly." Knowing the distinction (and, moreover, eating accordingly) can help ease blood-sugar woes and protect your health.

Take simple carbohydrates such as sugar, white bread, and white rice, for example. The body breaks down and quickly absorbs these foods; this process causes a spike in insulin. Over time, this pattern can cause insulin resistance in some people. Complex carbohydrates and protein, however, "take longer to digest and don't cause that spike in blood sugar, so insulin is released in a more desirable, gradual manner," explains Klauer. And while taking in fewer calories than you expend is still the way to lose weight, it's important to choose the right foods. "I see people counting calories and eating junk," Klauer says. "If those calories aren't from nutritious food, they may be thin, but they won't feel or look their best." Weil's perfect mix? Forty to 50 percent of calories from good carbohydrates (beans, winter squashes, whole grains, berries), 30 percent from good fats (olive oil, nuts, avocados), and 20 to 30 percent from healthy proteins (fish, soy, reduced-fat dairy products).

Myth: The less fat I eat, the better.
"There are still people who believe that fat intake should be kept as low as possible, Weil says. "What's more important are the kinds of fats you eat." Good fats like omega-3 fatty acids, which the body can't produce on its own, help with brain function and children's development, and they may stave off heart disease and arthritis.

In the kitchen, use extra-virgin olive oil for dressings and low-heat dishes and grapeseed or expeller-pressed, organic canola oil for high-heat cooking. "A lot of refined vegetable oils (corn, safflower) are high in omega-6s, which are pro-inflammatory," says Weil, adding that low-level inflammation may contribute to disease.

Packaged foods are a major source of unhealthy oils, so read ingredient lists carefully. "Avoid soy oil," he warns. "It may be one of the major pro-inflammatory fats in the American diet." And when it comes to anything generic like "vegetable oil," Weil says, there's no telling what's inside, so it's best to steer clear. How do you make the transition from a bad-fat diet to a good-fat diet? "Minimize your consumption of meat and full-fat dairy products, fast food, and products made with coconut and palm-kernel oil, partially hydrogenated oils, vegetable shortening, and common vegetable oils," Weil says. "Eat more wild salmon, flaxseed, olive oil, nuts, and avocados."