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Choosing Healthy Fats

Good Fats, Bad Fats, and the Power of Omega-3s

Salmon with lemon

Not all fat is the same. While bad fats can wreck your diet and increase your risk of certain diseases, good fats protect your brain and heart. In fact, healthy fats—such as omega-3s—are vital to your physical and emotional health. Understanding how to include more healthy fat in your diet can help improve your mood, boost your well-being, and even trim your waistline.

Fats and cholesterol

When it comes to dietary fat, what matters most is the type of fat you eat. Contrary to past dietary advice promoting low-fat diets, newer research shows that healthy fats are necessary and beneficial for health.

  • When food manufacturers reduce fat, they often replace it with carbohydrates from sugar, refined grains, or other starches. Our bodies digest these refined carbohydrates and starches very quickly, affecting blood sugar and insulin levels and possibly resulting in weight gain and disease.
  • Findings from the Nurses’ Health Study and the Health Professionals Follow-up Study show that no link between the overall percentage of calories from fat and any important health outcome, including cancer, heart disease, and weight gain.

Focus on "good" fat, not low-fat

Rather than adopting a low-fat diet, it’s more important to focus on eating beneficial “good” fats and avoiding harmful “bad” fats. Fat is an important part of a healthy diet. Choose foods with “good” unsaturated fats, limit foods high in saturated fat, and avoid “bad” trans fat.

  • "Good" unsaturated fats—Monounsaturated and polyunsaturated fats — lower disease risk. Foods high in good fats include vegetable oils (such as olive, canola, sunflower, soy, and corn), nuts, seeds, and fish.
  • "Bad" fats—Trans fats — increase disease risk, even when eaten in small quantities. Foods containing trans fats are primarily in processed foods made with trans fat from partially hydrogenated oil. Fortunately, trans fats have been eliminated from many of these foods.
  • Saturated fats, while not as harmful as trans fats, by comparison with unsaturated fats negatively impact health and are best consumed in moderation. Foods containing large amounts of saturated fat include red meat, butter, cheese, and ice cream.

When you cut back on foods like red meat and butter, replace them with fish, beans, nuts, and healthy oils instead of refined carbohydrates.

Omega-3 fatty acids

Eat at least Two 3-4 oz servings per week of fish and seafood including at least one serving of oily (dark meat) fish.

  • Why they help the heart. Oily, cold-water fish, such as salmon, herring, sardines, and tuna, contain EPA and DHA. These fats reduce the risk of fatal heart attacks and sudden cardiac death caused by electrical problems in the heart. Eating fish may reduce the risk of stroke as well. Fish also contain vitamin D, specific healthful proteins, selenium, and other nutrients.
  • Practical tip: choosing seafood. With the exception of commercially fried fish sticks and burgers, eating any fish or shellfish is likely to provide heart benefits, compared with eating none. All else being equal, fish and shellfish that contain higher levels of omega-3 fatty acids are likely to provide more benefit. For the average adult, the best advice is to eat a variety of different fish and shellfish, at least two servings each week, with at least one of these being an oily or dark meat fish.
Good sources of omega-3 fatty acids
Food Milligrams (mg) omega-3s per serving (3.5 oz or about 1/2 cup)

Anchovy

2,050

Herring, Atlantic

2,000

Salmon, farmed

1,950

Salmon, wild

1,850

Mackerel, Atlantic

1,200

Sardines, Atlantic

1,000

Bluefish

1,000

Trout

900

Tuna, white, albacore

850

Mussles

800

Bass, striped

750

Oysters, wild

500

Tuna, light

300

Halibut

200

Eggs

50 per egg

Who should consider fish oil capsules?

The American Heart Association (AHA) recommends that people with documented heart disease get about 1 gram of EPA plus DHA per day, preferably from fatty fish. But for many people, that goal may be tough to reach. You’d have to eat 2 to 3 ounces of wild salmon or 4 ounces of white tuna (canned in water) every single day. Other studies have suggested that a lower amount, about 250 mg of EPA plus DHA per day, may give you most of the benefit.

If you don’t care for fish (or that much fish), or you want to be sure to get your daily omega-3s, you may want to take fish oil capsules, which are widely available over the counter. Although the contents of these supplements aren’t directly regulated by the FDA, several studies have shown that the commonly available brands in reputable stores contain the stated ingredients. Fish oil contains no mercury (mercury binds to protein, not fat), and very low amounts of other contaminants.

One capsule a day usually supplies about 200 to 400 mg of EPA plus DHA, and should be enough for most people. Higher doses – 2 to 4 grams of EPA plus DHA per day – are needed for people who wish to substantially lower their triglycerides. If you’re one of these people, talk to your doctor about taking prescription fish oil, which has been concentrated to contain about 900 mg of EPA plus DHA per capsule.

For some, fish oil capsules can be hard to swallow and may leave a fishy aftertaste after burping. Keeping the capsules in the freezer before taking them can help or try odorless or deodorized capsules. For strict vegetarians, V-Pure capsules contain EPA and DHA extracted from algae, which is where fish get them.

Over all, although several trials have shown benefits of taking fish oil in different populations, remember that most long-term studies have evaluated people who eat fish. So eating fish ought to be your first choice for getting omega-3s, if possible.

Vegetable oils

Eat 5–6 teaspoons per day, including oil found in foods.

  • Why they're good for the heart. Vegetable oils lower LDL cholesterol and triglycerides, and raise HDL cholesterol. Vegetable oils that contain a type of polyunsaturated fat known as omega-6s (corn, sunflower, safflower, and soybean oils, to be specific) may also reduce insulin resistance and inflammation. Less processed oils, such as extra virgin olive oil, also contain potentially beneficial phytochemicals from the oil seeds.
  • Practical tips: choosing vegetable oils. Although olive oil, which is rich in monounsaturated fats, has received a lot of attention due to its prominent role in the traditional Mediterranean diet, the best scientific evidence supports the heart benefits of other vegetable oils that are rich in polyunsaturated fats, such as soybean or canola oil. However, all these vegetable oils improve blood cholesterol levels. So, choose any of these oils. If you like olive oil, look for extra virgin olive oil, which likely has extra heart benefits beyond regular olive oil.

What about tropical oils, such as coconut or palm oils? The food industry likes to tout the benefits of tropical oils, while dietary guidelines shun these oils. Who is right? These oils have complex effects on blood cholesterol levels—for example, raising “bad” LDL cholesterol but also raising “good” HDL cholesterol, among many other effects. Unfortunately, their effects on other risks for heart disease and, more importantly, on actual heart events (such as heart attacks) are almost wholly unknown. For now, stick to vegetable oils. There’s stronger evidence that these oils are heart healthy. If you do want to eat something once in a while that contains coconut or palm oil, enjoy it as a treat—it’s better than eating something with trans fat, which these tropical oils often replace.

More help for healthy eating

Resources and references

Fats and Cholesterol - Information on the different kinds of fats and their affect on cholesterol (Harvard University, School of Public Health)

Healthy Eating for a Healthy Heart - Includes information on how diet affects your heart, and how you can eat to foster heart health. (Harvard Health Publications

Healthy Fats – Explains the different types of fats and how much of them should be included in a healthy diet. (University of Michigan)

Saturated Fats – Outlines the long-held view that saturated fats raise cholesterol and increase the risk of heart disease and stroke. (American Heart Association)

Fats – Differentiates between healthy fats and unhealthy fats, including saturated fat, which should be limited for people with diabetes to prevent heart disease and stroke. (American Diabetes Association)

Dietary Guidelines for Americans – Summary of dietary guidelines, including recommended saturated fat limits. (USDA)

Omega-3 fatty acids – Comprehensive article on omega-3 fatty acids and the role they may play in preventing several diseases and conditions. (University of Maryland Medical Center)

Authors: Robert Segal, M.A. Last updated: April 2017.