Good Fats, Bad Fats: How to Choose

Eating fat can be heart-healthy if you pick the right kind. Too many of us cut fat willy-nilly and replace it with refined carbs, so we miss out on the benefits of healthy fats, says Suzanne Rostler, a registered dietitian and nutritionist in Framingham, Mass. What’s more, eating lots of refined carbs—like white bread and white rice—can increase triglyceride levels, which can contribute to heart and blood vessel disease.

Adults should get 20% to 35% of their calories from fat, according to the 2010 Dietary Guidelines for Americans. Here’s how to make sure you’re getting enough of the right kind.

Goal: Get more!

You can find polyunsaturated fats in nuts, seeds, vegetable oils such as corn and safflower oil, and fatty fish. This category encompasses omega-3 and omega-6 fatty acids, which are known as essential fatty acids because our bodies don’t make them—we have to get them from food.

Polyunsaturated fats can help lower your total cholesterol level, says Sari Greaves, a registered dietitian and nutrition director at Step Ahead Weight Loss Center, in Bedminster, N.J.

Goal: Limit

Saturated fat increases total cholesterol and LDL, and may boost your type 2 diabetes risk. Meat, seafood, and dairy products are sources of saturated fat. Some plant foods, like palm and coconut oil, also contain it. Animal or vegetable, saturated fat carries the same risks.

Choose low-fat or fat-free dairy products to get their key nutrients while cutting saturated fat.

The Dietary Guidelines recommend no more than 10% of total calories come from saturated fat. So if you eat 2,000 calories a day, for example, keep your saturated fat intake below 22 grams.

Goal: Get more!

Unsaturated fats are mostly good guys—although trans fat is technically an unsaturated fat. However, healthy unsaturated fats are liquid at room temperature, while trans and saturated fats are solid.

To increase your unsaturated fat, replace solids, like butter, with olive and vegetable oils, and swap red meat for seafood or unsalted nuts. (Seafood and nuts also contain saturated fat, but usually less than red meat.)

The two main types of unsaturated fats are monounsaturated and polyunsaturated fats; their chemical structure is slightly different, as are their health benefits.

Goal: Limit

Scientific understanding of the dangers of dietary cholesterol has shifted. "It used to be thought that eating dietary cholesterol, like in shrimp or eggs, would raise cholesterol," Rostler explains. "It does to some extent, but it’s more important to focus on not eating saturated and trans fats."

For people with normal cholesterol levels, Rostler says, the current recommendation is no more than 300 milligrams of cholesterol daily, while people at high risk of heart disease should consume less than 200 milligrams daily. For perspective, one egg contains about 200 milligrams of cholesterol.

Goal: Get more!

Monounsaturated fats raise HDL (good cholesterol) and lower LDL. Canola oil, olive oil, peanut oil, nuts, seeds, and avocados are good sources.

Trade sour cream dip for hummus (which is rich in olive oil) or guacamole; use veggies or whole-wheat chips to dip. Try peanut oil in a stir-fry to jazz up your diet while helping your heart, says Greaves, who is also an American Dietetic Association spokesperson and coauthor of The Cardiac Recovery Cookbook.

Unsalted nuts contain monounsaturated fat, but they’re high in calories. Sprinkle them on salads or yogurt, rather than eating a 170-calorie handful.

Goal: Get more!

In the world of good fats, omega-3s are superstars. They fight inflammation, help control blood clotting, and lower blood pressure and triglycerides.

Fatty fish like albacore tuna, salmon, mackerel, and sardines are good sources, Greaves says. You don’t have to break the bank to get them; canned Alaskan salmon and canned sardines are okay too.

Vegetable sources include soy, walnuts, and some vegetable oils. There are no specifics on how much you should consume, but the American Heart Association suggests eating at least two 3.5-ounce servings of fish each week.

Goal: Jury still out

Most of us have no trouble getting enough omega-6s, which are found in vegetable oils and many snack foods.

The ratio of omega-6s to omega-3s in the typical Western diet is around 10 to 1. Some research suggests that between a 2-to-1 and a 4-to-1 ratio reduces the risk of death from heart disease.

There has been some controversy over whether omega-6s can actually be harmful to the heart, but Greaves and Rostler agree that as long as you’re eating them instead of saturated or trans fats, and you make a point of upping your omega-3 intake, you’ll be helping your ticker.