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Choosing Healthy Fats

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

Salmon with lemon

For years, nutritionists and doctors have preached that a low-fat diet is the key to losing weight and preventing health problems. However, 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.

Why are we so afraid of fat?

A walk down any grocery store aisle will confirm our obsession with low- and no-fat foods. We’re bombarded with supposedly guilt-free options: fat-free milk, cheese, and yoghurt, low-fat cookies, cakes, and frozen dinners. But while our low-fat options have exploded, so have obesity rates. Clearly, all these low-fat foods haven’t delivered on their trim, healthy promises.

The reason for that is simple: not all fat is bad. In fact, your body needs fat. Healthy or “good” fats are essential to help manage your moods, stay on top of your mental game, fight fatigue, and even control your weight. Since the human brain is nearly 60 percent fat, healthy fats are also vital for proper brain development and function. The answer isn’t cutting out the fat—it’s learning to make healthy choices and to replace bad fats with good ones that promote health and well-being.

Myths and facts about dietary fat

Myth: All fats are equal—and equally bad for you.

Fact: Some fats raise your cholesterol and increase your risk for heart disease, while others lower cholesterol, reduce your risk of heart disease, and provide other health benefits.

Myth: Fat-free means healthy.

Fact: A “fat-free” label doesn’t mean you can eat all you want without consequences to your waistline. Many fat-free foods are high in sugar, refined carbohydrates, and calories.

Myth: Eating a low-fat diet is the key to weight loss.

Fact: The obesity rates for Americans have doubled in the last 20 years, coinciding with the low-fat revolution. Cutting calories is the key to weight loss, and since fats are filling, they can help curb overeating.

Good fats vs. bad fats

There are four major types of dietary fat found in food from plants and animals:

  • Good: monounsaturated and polyunsaturated fats (including omega-3s)
  • Bad: trans fats
  • Open to debate: saturated fats

However, to label certain fats “good” and others “bad” can be a little simplistic. After all, it takes more than just the fat content of food to determine whether it’s healthy or unhealthy. Other factors include how food is raised or grown, how it’s prepared, and any additives used can make a huge difference to whether something is healthy or unhealthy. While some fish is packed with healthy omega-3 fats, for example, deep frying it in refined vegetable oil can add unhealthy trans fat, making it potentially harmful. And while monounsaturated and polyunsaturated fats from whole foods are universally considered good fats, those from industrially manufactured oils are often considered dangerous.

The debate over saturated fat

There’s an ongoing debate in the nutrition world about the merits and dangers of saturated fat and no clear consensus on exactly where it falls on the spectrum of good fats to bad. While many prominent health organizations maintain that eating saturated fat from any source increases the risk of heart disease and stroke, other nutrition experts argue that it contributes to weight control and overall health.

Tips for adding more healthy unsaturated fat to your diet

These good fats can improve blood cholesterol levels, lower your risk of heart disease, and benefit insulin levels and blood sugar. Omega-3 fats are particularly beneficial for your brain and mood. The best sources are fish, nuts, and seeds.

Good Fats
Monounsaturated fat
  • Avocados
  • Olives
  • Nuts (almonds, peanuts, macadamia nuts, hazelnuts, pecans, cashews)
  • Natural peanut butter (containing just peanuts and salt)
Polyunsaturated fat
  • Walnuts
  • Soymilk and tofu
  • Sunflower, sesame, flax, and pumpkin seeds
  • Fatty fish (salmon, tuna, mackerel, herring, trout, sardines)

Beware of certain unsaturated oils

There are basically two types of unsaturated vegetable oils:

  1. Traditional, cold-pressed oils such as extra virgin olive oil, peanut oil, and sesame oil that are rich in monounsaturated fats and made without the use of chemicals or heat.
  2. Modern processed oils such as soybean oil, sunflower oil, corn oil, canola oil, cottonseed oil, and safflower oil which are industrially manufactured—usually from genetically modified crops in the U.S.—using heat and toxic solvents.

Some nutritionists feel that these manufactured vegetable oils shouldn’t be included as “good” fats because the damaging industrial processing can transform the fatty acids into dangerous trans fat.

When good fats go bad

A good fat can become bad if heat, light, or oxygen damages it.

  • Polyunsaturated oils must be refrigerated.
  • Cooking at high heat with some unsaturated oils can damage the fat.
  • Discard oils, seeds, or nuts if they smell or taste bitter.

Olive oil fraud

A lot of imported "olive oil" is actually a combination of olive oil and cheaper, refined oil. To protect yourself:

  • Opt for olive oil with the California Olive Oil Council (COOC) logo on a bottle.
  • For olive oils from France: look for the “AOC” logo, from Italy: the “DOP” logo, and from Spain: the “DO” seal.

Source: Berkeley Wellness

Choosing healthy fats tip 3: Eat omega-3s often

Omega-3 fatty acids are a type of polyunsaturated fat. While all types of monounsaturated and polyunsaturated fats are good for you, omega-3 fats are proving to be especially beneficial. Research has shown that they can:

  1. Prevent and reduce symptoms of depression, ADHD, and bipolar disorder
  2. Protect against memory loss and dementia
  3. Reduce the risk of heart disease, stroke, and cancer
  4. Ease arthritis, joint pain, and inflammatory skin conditions
  5. Support a healthy pregnancy
  6. Help you battle fatigue, sharpen your memory, and balance your mood

The different types of omega-3 fatty acids:

EPA and DHA found in fish and algae have the most health benefits.

ALA comes from plants and is a less potent form of omega-3 than EPA and DHA, although the body does convert ALA to EPA and DHA at low rates.

The best sources of omega-3s

While most of us obtain plenty of omega-6 fats in our diets, we need to increase our intake of omega-3s to maintain a healthy ratio.

Fish: the best sources of omega-3s
  • Salmon (especially wild-caught king and sockeye)
  • Herring
  • Mackerel
  • Anchovies
  • Oysters
  • Sardines
  • Pole and line-caught tuna
  • Lake trout
Vegetarian sources of omega-3s
  • Algae such as seaweed (high in EPA and DHA)
  • Brussels sprouts
  • Walnuts
  • Flazseed
  • Fish oil or algae supplements
  • Kale
  • Spinach
  • Parsley

Mercury in fish

Despite the health benefits, nearly all seafood contains traces of pollutants, including the toxic metal mercury. The concentration of pollutants increases in larger fish, so avoid eating shark, swordfish, tilefish, and king mackerel.

Check local seafood advisories to learn if fish you’ve caught is safe to eat.

Most adults can safely eat 12 ounces (two 6-ounce servings) of cooked seafood a week. For women who are pregnant, nursing mothers, and children under 12, choose fish lower in mercury, such as shrimp, canned light tuna, salmon, pollock, or catfish. Eat no more than 6 ounces (one average meal) of albacore tuna per week.

Fish fraud

In 2013 testing, one third of fish in the U.S. was found to be mislabeled. Similar fraud has been exposed in almost every other part of the world. Fraudulent labels are most commonly put on fish sold as cod, grouper, red snapper, and wild salmon. To protect yourself:

  • Find a reputable fishmonger you can trust.
  • Buy whole fish when possible.

Source: Berkeley Wellness

If you don’t eat fish, consider taking an omega-3 supplement

While omega-3s are best obtained through food, there are many omega-3 and fish oil supplements available.

Avoid products that don’t list the source of their omega-3s. The package should list the source of omega-3 fatty acids as fish oil, krill oil, or algae.

Look for the total amount of EPA and DHA on the label. The bottle may say 1,000 milligrams of fish oil, but it’s the amount of omega-3 that matters.

Choose supplements that are mercury-free, pharmaceutical grade, and molecularly distilled. Supplements derived from molecularly distilled fish oils tend to be naturally high in EPA and DHA and low in contaminants. Choose a supplement that has been independently tested to be free of toxins.

How much omega-3 do I need?

For most people, two 6 oz. servings of fatty fish a week, as well as regular servings of ALA-rich vegetables provides a healthy amount. For fish oil supplements, look for 700-1,000 mg of EPA and 200-500 mg of DHA daily. Many algae supplements have a lower recommended dose due to the higher concentration of omega-3s.

Eliminate trans fat from your diet

Small amounts of naturally occurring trans fats can be found in meat and dairy products but it’s artificial trans fats that are considered dangerous. These dangerous trans fats are normal fat molecules that have been deformed during a process called hydrogenation, where liquid vegetable oil is heated and combined with hydrogen gas. Partially hydrogenating vegetable oils makes them more stable and less likely to spoil.

No amount of artificial trans fats is healthy. Trans fats raise your LDL ("bad") cholesterol and lower your HDL ("good") cholesterol and increases your risk of heart disease, stroke, and diabetes.

Look for hidden trans fat in your food

The USDA recommends limiting trans fat to no more than 2 grams per day; many other authorities recommend eliminating it altogether. In the U.S., if a food has less than 0.5 grams of trans fat in a serving, food companies can label a product as having 0 grams. You may think that what you’re eating is safe but all those small amounts can quickly add up to dangerous levels, especially if you consume more than the recommended serving.

Check the food’s ingredients. If it lists “partially hydrogenated” oil then the food contains trans fat.

Reduce fried food. While there’s a movement to ban trans fat in the U.S., that won’t make your French fries any healthier if they’re cooked in vegetable oils that oxidize when heated. It’s safer to cut down on fried foods altogether.

Avoid fast food. Most states have no labeling regulations for fast food, and it can even be advertised as cholesterol-free when cooked in vegetable oil.

When eating out, talk to your server. Ask if your food can be prepared using olive oil instead of partially hydrogenated oil.

Common sources of bad trans fat

  • Commercially baked goods (cookies, crackers, cakes, muffins, pie crusts, pizza dough, breads like hamburger buns)
  • Packaged snack foods (crackers, microwave popcorn, chips, candy)
  • Solid fats (stick margarine, vegetable shortening)
  • Fried foods (French fries, fried chicken, chicken nuggets, breaded fish, hard taco shells)
  • Pre-mixed products (cake mix, pancake, chocolate milk)
  • Anything with "partially hydrogenated" oil listed in the ingredients

Be smart about saturated fat

Prominent organizations such as the American Heart Association and the American Diabetes Association maintain that eating saturated fat from any source increases the risk of heart disease and stroke. However, other nutrition experts take a more relaxed view about eating saturated fat from high-quality sources of dairy and meat. They maintain that eating grass-fed meat, free-range poultry, and organic or raw dairy products doesn’t carry the same health risks as consuming saturated fat from an animal that’s been fed an unnatural diet of corn and hormones and medication.

  • A recent study published in the Annals of Internal Medicine indicates that people who eat saturated fat do not experience more cardiovascular disease than those who eat less.
  • A meta-analysis of 16 studies published in the European Journal of Nutrition shows that eating whole-milk dairy products is linked to less body fat and lower levels of obesity.
  • This may be because full-fat dairy makes you feel fuller, faster, and keeps you feeling satisfied for longer, thus helping you to eat less overall.
  • Adding a little tasty fat—such as butter—to a plate of vegetables, for example, can make it easier to eat healthy food and thus improve the overall quality of your diet.

Making healthier saturated fat choices

  • Avoid saturated fat from processed meats, packaged meals, and takeout food.
  • Don’t replace high quality sources of saturated fat with refined carbs or sugary snacks.
  • Don’t eat just red meat (beef, pork, or lamb) but vary your diet with free range chicken, eggs, fish, and vegetarian sources of protein.
  • If you choose to eat red meat, look for "organic" and “grass-fed”.
  • Roast, grill, or slow cook meat and poultry instead of frying.
  • Enjoy full-fat dairy in moderation and choose organic or raw milk, cheese, butter, and yoghurt when possible.
  • Avoid snack foods such as corn or potato chips.

Focus on fat from real food, not processed food

There are many opinions and few absolutes in the nutrition world. For most of us, it’s our overall dietary pattern that is more important than specific foods. What we do know for sure is that the typical Western diet—filled with fried, processed food, packaged meals, and sugary snacks—is leading to higher rates of obesity and illness. Eating less processed food and more “real,” natural food—fresh from the ground, the ocean, or small, local farms—is a sound place to start for all your food choices, including healthy fats.

Related HelpGuide articles

Resources and references

Types of fats: Good fats, bad fats

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

Figuring Out Dietary Fats – Outlines the importance of eating the right fats, rather than no fats. (Berkeley Wellness)

Beware of Food Fraud – Outlines the problem of fraudulent labeling of olive oil, fish, and other foods. (Berkeley Wellness)

The debate about saturated fat

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)

The Full-Fat Paradox – New research that concludes the consumption of whole-fat dairy is linked to reduced body fat. (NPR)

The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease – Abstract of research that suggests high-fat dairy consumption is inversely associated with obesity risk. (NCBI)

Association of Dietary, Circulating, and Supplement Fatty Acids with Coronary Risk – Summary of research that concludes people who eat lots of saturated fat do not experience more cardiovascular disease than those who eat less. (Annals of Internal Medicine)

The End of the Debate? Fat Chance – Discusses the debate about saturated fats. (Berkeley Wellness)

Don't Fear the Fat – Experts question the existing saturated fat guidelines. (NPR)

The Diet-Heart Myth: Cholesterol and Saturated Fat Are Not the Enemy – Nutritionist who takes a different view on saturated fat and the existing dietary guidelines. (Chris Kesser)

Red meat and processed meat

More Reason to Avoid Processed Meat – The link between processed meat and increased risk of heart failure. (Berkeley Wellness)

Antibiotic Overuse in Animals – The dangers of antibiotics in the U.S. being prescribed to promote growth in livestock. (Berkeley Wellness)

World Health Organization Says Processed Meat Causes Cancer – Details the link between processed meat and certain types of cancer. (American Cancer Society)

Unsaturated oils

Canola Oil Myths and Truths – A look at the health benefits and dangers of using canola oil. (Berkeley Wellness)

Omega-3 fatty acids

Omega-3 Fats: An Essential Contribution – All about the health benefits of the important omega-3 fatty acids, including the best food sources in which to find them. (Harvard School of Public Health)

Omega-3 Fatty Acids – Simple charts listing omega-3 fatty acid content of selected foods. (Tufts University)

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)

Trans fats

Trans Fat is Double Trouble for Your Heart Health – How trans fat lowers good and raises bad cholesterol. (Mayo Clinic)

FDA to cut trans fats from food – Outlines plans to ban artificial trans fats from a wide range of foods in 2018. (Reuters)

From our readers:

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Authors: Lawrence Robinson and Jeanne Segal Ph.D. Last updated: December 2016.