4. Lower doesn't always mean better It's true that a diet high in fat is usually high in calories too, which raises your risk of becoming obese and developing chronic diseases, like heart disease and diabetes, but going too low can also be bad for your health. Research in the Journal of the American Medical Association found that people who consumed a mere 20 percent of their calories from fat had the same rates of heart attack, stroke, and certain cancers as those who ate nearly twice as much.

So just how much of the nutrient is enough? Experts recommend getting roughly 25 to 35 percent of your total calories from fat. For a woman who eats 1,500 calories a day, that's about 50 grams, or the amount in 3 ounces of sirloin, half an avocado, 2 tablespoons of peanut butter, and two cookies. (To see exactly how much you need, go to myfatstranslator.com.) These recommendations aren't meant to be followed everyday though. It's more important to average out your fat intake over the course of a week, meaning you can eat a little more one day and a little less the next.

5. Fish contains the healthiest fats Although there's no such thing as a cure-all, omega-3 fatty acids come pretty close. Research reveals that this type of polyunsaturated fat (found in cold-water fish, like salmon, sardines, anchovies, and flounder, as well as flaxseed, walnuts, omega-3-fortified eggs, and red meat from grass-fed animals) can do everything from lower your blood pressure and cholesterol levels to fight memory loss and improve your skin. Some experts say they can even perk up your mood and defend against depression.

But not all types of omega-3s are equally beneficial. While the three main varieties—ALA, DHA, and EPA—are all good for you, the latter two are the more potent disease fighters. Plant sources, like nuts and seeds, are where ALA can be found. EPA and DHA are found in algae, which fish and shellfish eat, making them both excellent sources. To get enough of these nutrients, dine on salmon or another type of fatty fish at least twice a week. Not a fan of fillets? Opt for a daily fish oil capsule that's free of mercury and other contaminants. And for a supplement that's just as effective at raising your body's omega-3 levels as seafood—without the fishy aftertaste—try a DHA supplement derived from algae or krill oil.