Helpguide Logo

Help yourself to greater health and happiness

Friends of HelpGuide

Choosing Healthy Fats

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

Healthy fats In This Article

For years, nutritionists and doctors have preached that a low-fat diet is the key to losing weight, managing cholesterol, and preventing health problems. But more than just the amount of fat, it’s the types of fat you eat that really matter. Bad fats increase cholesterol and your risk of certain diseases, while good fats protect your heart and support overall health. In fact, good fats—such as omega-3 fats—are essential to physical and emotional health.

Making sense of dietary fat

Dietary fats are found in food from plants and animals. The four major types are:

  • monounsaturated fats
  • polyunsaturated fats (including omega-3s)
  • trans fats
  • saturated fats

Despite what you may have been told, not all fats are bad guys in the waistline wars. While dietary fats all contain 9 calories per gram, they can have very different effects on your health as well as your weight. “Bad” fats, such as trans fats, are guilty of the unhealthy things all fats have been blamed for—weight gain, clogged arteries, and so forth. But good fats such as omega-3s have the opposite effect. In fact, healthy fats play a huge role in helping you manage your moods, stay on top of your mental game, fight fatigue, and even control your weight.

The answer for a healthy diet isn’t to cut out the fat—it’s to replace bad fats with the good ones that promote health and well-being.

Unsaturated fats and oils

Unsaturated fats are considered “good” fats and are encouraged as part of a healthy diet. Eating foods rich in monounsaturated and polyunsaturated fat can improve blood cholesterol levels and lower your risk of heart disease. These fats may also benefit insulin levels and controlling blood sugar, which can be especially helpful if you have type 2 diabetes. These good fats include:

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
  • Sunflower, sesame, and pumpkin seeds
  • Flaxseed
  • Fatty fish (salmon, tuna, mackerel, herring, trout, sardines)
  • Non-GMO sources of soymilk and tofu

Unsaturated oils

We’ve long been told that the simplest way to prevent heart disease is to swap saturated fats for their healthier, unsaturated counterparts. That means swapping butter for margarine and cooking in unsaturated vegetable oils instead of lard. However, new research suggests that things aren’t that simple.

There are basically two types of unsaturated vegetable oils: Firstly, traditional, cold-pressed oils such as extra virgin olive oil, peanut oil, and sesame oil (widely used in Asian cooking) that are rich in monounsaturated fats and have been used for hundreds of years. Cold-pressed oils are made without the use of chemicals or heat to extract the oil from seeds or nuts.

Secondly, there are the more recently developed processed oils such as soybean oil, sunflower oil, corn oil, canola oil, cottonseed oil, and safflower oil. These oils are industrially manufactured—usually from genetically modified crops in the U.S.—using high heat and toxic solvents to extract the oil from the seeds.

Some nutritionists feel that these manufactured vegetable oils shouldn’t be included as “good” fats because the industrial processing can damage the oil and transform the fatty acids into dangerous trans fat. Their high omega-6 content can also unbalance the ratio of omega-6s to omega-3s that are crucial to good health.

Damaged fat: When good fats go bad

A good fat can become bad if heat, light, or oxygen damages it. Oils that are high in polyunsaturated fats (such as flaxseed oil) must be refrigerated and kept in an opaque container. Never use oils, seeds, or nuts after they begin to smell or taste rank or bitter. Cooking at high heat with some monounsaturated or polyunsaturated oils can also damage the fat.

Omega-3 fatty acids: Superfats for the brain and heart

Omega-3 fatty acids, a type of polyunsaturated fat, play a vital role in cognitive function (memory, problem-solving abilities, etc.) as well as emotional health. Research has shown that they can:
  • Prevent and reduce the symptoms of depression, ADHD, and bipolar disorder
  • Protect against memory loss and dementia
  • Reduce the risk of heart disease, stroke, and cancer
  • Ease arthritis, joint pain, and inflammatory skin conditions
  • Support a healthy pregnancy
  • Help you battle fatigue, sharpen your memory, and balance your mood

The different types of omega-3 fatty acids:

  • EPA and DHA – Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have the most research to back up their health benefits. Both are found in abundance in cold-water fatty fish.
  • ALA – Alpha-linolenic acid (ALA) comes from plants. Studies suggest that it’s 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 ALA include flaxseed, walnuts, and canola oil.

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 of 6s to 3s.

Good Fats

Fish: the best source 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)
  • Fish oil or algae supplements
  • Walnuts
  • Flaxseed
  • Brussels Sprouts
  • Kale
  • Spinach
  • Parsley

What to do about mercury in fish

Despite all the health benefits of seafood, nearly all fish and shellfish contain traces of pollutants, including the toxic metal mercury. These guidelines can help you make the safest choices.

  • The concentration of mercury and other pollutants increases in larger fish, so it’s best to avoid eating large fish like shark, swordfish, tilefish, and king mackerel.
  • Most adults can safely eat about 12 ounces (two 6-ounce servings) of other types of cooked seafood a week.
  • Pay attention to local seafood advisories to learn if fish you’ve caught is safe to eat.
  • For women who are pregnant, nursing mothers, and children aged 12 and younger, choose fish and shellfish that are lower in mercury, such as shrimp, canned light tuna, salmon, pollock, or catfish. Because of its higher mercury content, eat no more than 6 ounces (one average meal) of albacore tuna per week.

Choosing the best omega-3 supplement

While omega-3s are best obtained through the food that you eat, there are many different omega-3 and fish oil supplements available. Use these tips to help you make the best selection:

  • 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, expressed in milligrams of EPA and DHA. Look to achieve your daily intake in the smallest number of pills.
  • 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 heavy metals such as mercury and lead, and other 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 foods such as flaxseed or walnuts, provides a healthy amount. If you opt for fish oil supplements, look for 700 to 1,000 mg of EPA and 200 to 500 mg of DHA per day. Many algae supplements have a lower recommended dose than fish oil supplements due to the higher concentration of omega-3s.

Getting more good fats in your diet

The best sources of healthy monounsaturated and polyunsaturated fats are fish, nuts, seeds, and cold-pressed vegetable oils.

  • Make friends with olive oil. Use cold-pressed extra-virgin olive oil to dress salads, cooked vegetables, or pasta dishes. Also use olive oil for stovetop cooking, rather than stick margarine or canola oil. For baking, most chefs prefer butter or ghee (clarified butter).
  • Dress your own salad. Commercial salad dressings are often high in calories, saturated fat, or made with damaged trans fat oils. Create your own healthy dressings with extra virgin olive oil, flaxseed oil, or sesame oil.
  • Eat more avocados. Try them in sandwiches or salads or make guacamole. Along with being loaded with heart and brain-healthy fats, they make for a filling and satisfying meal.
  • Reach for the nuts. You can also add nuts to vegetable dishes or use them instead of breadcrumbs on chicken or fish.
  • Snack on olives. Olives are high in healthy monounsaturated fats. But unlike most other high-fat foods, they make for a low-calorie snack when eaten on their own. Try them plain or make a tapenade for dipping.

Trans fat: eliminate this bad fat from your diet

Small amounts of naturally-occurring trans fats can be found in meat and dairy products but it’s the artificial trans fats that are considered dangerous. These are normal fat molecules that have been twisted and deformed during a process called hydrogenation. During this process, liquid vegetable oil is heated and combined with hydrogen gas. Partially hydrogenating vegetable oils makes them more stable and less likely to spoil, which is very good for food manufacturers—and very bad for you.

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

Bad Fats

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

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 trans fat. You may think that what you’re eating is safe but all those small amounts can quickly add up to dangerous levels of trans fat, especially if you consume more than the recommended serving.

  • Check the food’s ingredients. If it lists “partially hydrogenated” oil then the food contains some trans fat.
  • When eating out, put fried foods, biscuits, and other baked goods on your “skip” list.
  • 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, ask your server what type of oil your food will be cooked in. If it’s partially hydrogenated oil, run the other way or ask if your food can be prepared using olive oil.

Saturated fat: good or bad?

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. In fact, a meta-analysis of 16 studies published in the European Journal of Nutrition shows that eating whole-milk dairy products is actually 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 also make it easier to eat healthy food and thus improve the overall quality of your diet.

The debate about saturated fats

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, while other nutrition experts take a more relaxed view about eating saturated fat in moderation from high-quality sources of dairy and meat. As a result there’s an ongoing debate 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.

According to some nutritionists, not all saturated fat is the same. The saturated fat in whole milk, coconut oil, or salmon, for example, is different to the saturated fat found in pizza, French fries, and processed meat products (such as ham, sausage, hot dogs, salami, and other cold cuts) which have been linked to coronary disease and cancer. And just as saturated fat varies according to its source, the effect of saturated fats on blood cholesterol appears to vary from person to person, depending on genetics and other health factors. While some at-risk groups of people would be wise to restrict the amount of saturated fat they consume, others may be able to enjoy more high quality sources of saturated fat than the current dietary guidelines suggest.

The dangers of replacing saturated fat with sugar

A walk down any grocery store aisle will confirm our obsession with foods low in saturated fat. We’re bombarded with supposedly guilt-free options: baked potato chips, fat-free milk, cheese, yogurt and ice cream, and low-fat candies, cookies, and cakes. But while our low-fat options have exploded, so have obesity rates. Clearly, low-fat foods and reduced fat diets haven’t delivered on their trim, healthy promises.

Part of the problem is that many of us have swapped dairy and animal fats in our diets for refined carbohydrates and sugar, which we now know have a tremendously negative effect on both weight and heart health. So instead of eating whole-fat yoghurt, for example, we’re eating low- or no-fat versions that are packed with added sugar to make up for the loss of taste. Or we’ve swapped our breakfast bacon for a pastry or muffin. In other words, we’ve swapped one thing in our diets for something that’s much worse.

Red meat vs. grass-fed red meat

There are many reasons to consider limiting your consumption of red meat—including the damaging environmental impact of raising cattle and the treatment of industrially-raised animals. In countries like the U.S., for example, animals are typically denied access to the outdoors, pumped full of antibiotics and growth hormones, and given GMO feed grown with pesticides. When these additives enter the food chain they are mainly stored in the fat of an animal—which may be a good reason for not eating too much animal fat. There may even be a link between processed meats and cancer.

However, proponents of the saturated fat movement believe that eating grass-fed meat, free-range poultry, and organic or raw dairy products doesn’t carry the same health risks as consuming their processed cousins. The content of a piece of organic, grass-fed beef, they argue, is different than the content from an animal that’s been fed an unnatural diet of corn and hormones and medication—and that makes it better for you.

Making smart choices about saturated fat

Unlike trans fat, there’s no need for people in good health to try to eliminate saturated fat from your diet. The USDA recommends limiting saturated fat to 20 grams a day for someone on a 2,000 calorie diet. Other experts prefer to focus on the source of saturated fats consumed rather than on specific numbers: A glass of whole milk rather than a hot dog, for example, grilled chicken or fish instead of fried chicken, or a 4 oz. portion of grass-fed beef rather than a processed burger and French fries. To help you make healthier 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 breaded meats and vegetables and deep-fried foods.
  • Avoid snack foods such as corn or potato chips.

General guidelines for choosing healthy fats

If you are concerned about your weight or overall health, rather than avoiding fat in your diet, try replacing trans fats and saturated fats from fried or processed foods with good fats, such as fish, olive oil, nuts, avocados, and high-quality dairy.

  • Try to eliminate trans fats from your diet. Check food labels for trans fats or any kind of “partially hydrogenated” oil. Avoiding commercially-baked goods, margarines, and limiting fast food goes a long way to cutting out this dangerous fat from your diet.
  • Reduce or eliminate fried food. While there’s a movement to ban trans fat in the U.S., that won’t necessary make your French fries any healthier, especially if the food industry decides to cook them in vegetable oils that oxidize when heated. The safer option is to cut down on fried foods altogether.
  • Eat omega-3 fats every day. Good sources include fish and fish oil, walnuts, flax seeds, and flaxseed oil. Try adding ground flaxseed meal to your breakfast cereal or instigating a “fish Friday.”
  • Choose your oils carefully. Cold-pressed, organic oils retain all the nutrients that are burned away in industrially manufactured oils, many of which can become toxic when heated.

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 manufactured and industrially-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 dietary 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)

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)

What other readers are saying

“GOOD GRIEF! Your article on Choosing Healthy Fats is amazing! It is clear, concise, logical, explanatory and prescriptive without being preachy. In one fell swoop, you've answered every question I had about fats and oils. Outstanding job. I look forward to more of your articles.” ~ Nevada

“I'd like to thank everyone involved with this article. I saved it as a bookmark in my smartphone and use it daily as a guide/reference. It really is tremendous – from the highly valuable information to its user-friendliness. The fact that there's such thing as good fats isn't new to me, but this article provides more information about good fats than I previously knew and it's very well laid out and to the point. It's truly a joy to use.” ~ Illinois

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