What Are Polyunsaturated Fats?

polyunsaturated fat sources
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Polyunsaturated fat is a type of unsaturated dietary fat that provides health benefits when eaten in moderation. Examples of polyunsaturated fats include walnuts, many varieties of seeds and some types of fish. Oils that contain polyunsaturated fatty acids are liquid at room temperature and have a shorter shelf life than other types of fat.

The Difference Between Polyunsaturated Fat and Other Dietary Fats

Dietary fat is fat that comes from the food we eat.

It's different than the fat that our body makes when we consume too many calories. Polyunsaturated fat is one type of dietary fat. But there are several other kinds of dietary fat including saturated fat, trans fat and monounsaturated fat.

Polyunsaturated fats are foods that are made up primary of polyunsaturated fatty acids (PUFAs). These fatty acids have a chemical structure that contains a double bond between two or more sets of carbon atoms. Polyunsaturated fatty acids are similar to monounsaturated fatty acids (MUFAs) that contain just one double bond between two carbons. 

Both monounsaturated fats and polyunsaturated fats can be healthy for your body when you eat them in moderation. 

Benefits of Polyunsaturated Fats

Your body needs fat to carry out essential functions. Fat insulates your body, fat helps your cells to function properly, and you need fat to absorb certain essential vitamins.

But polyunsaturated fats provide special benefits.

Polyunsaturated fats provide essential nutrients like vitamin E. Vitamin E is an antioxidant that helps protect your body's cells.

Polyunsaturated fats also provide omega-3 and omega-6 fatty acids. Omega-3 fatty acids have been shown to improve blood flow, reduce inflammation and improve heart health.

Some researchers also believe that a diet high in omega-3s can help improve brain health.

Most experts recommend that you get the recommended dose of omega-3 fatty acids from polyunsaturated fat foods, rather than from a supplement.

Examples of Polyunsaturated Fat Foods

Polyunsaturated fats are found in many healthy foods that you may already eat on a regular basis. You'll find polyunsaturated fats in many varieties of fish, nuts and plant-based oils.

Fish sources of PUFAs

  • Trout
  • Albacore tuna
  • Salmon
  • Herring
  • Mackerel

Nut and Seed Sources of PUFAs

  • Walnuts
  • Sunflower seeds
  • Flax seeds
  • Chia seeds
  • Sesame seeds

Oil Sources of PUFAs

  • Soybean oil
  • Corn oil
  • Sunflower oil
  • Flax seed oil
  • Safflower oil

Tofu and soybeans are also good sources of polyunsaturated fat.

Should I Eat Polyunsaturated Fat to Lose Weight?

Even though polyunsaturated fats provide important benefits for your body, you shouldn't necessarily eat more fat to improve your health. Like all fat, polyunsaturated fat provides 9 calories per gram. That means that when you eat foods high in polyunsaturated fat, you are eating foods that are higher in fat and calories.

Eating too many or too much of these foods may contribute to weight gain and can weight loss harder.

If you're trying to lose weight, you should limit your fat intake. Most experts recommend that you get no more than 30% of your total calories from fat. The USDA Dietary Guidelines recommend that you consume less than 10% of your total calories from saturated fat. So it's best to get most of your fat from polyunsaturated or monounsaturated fat foods. 

How to Shop For Polyunsaturated Fats

So how to you find polyunsaturated fats when you shop? Some nutritional labels provide detailed information about the type of fat in your food. But most do not. So you have to know where to find polyunsaturated fat foods in the grocery store.

Dairy and meat products usually contain saturated fat. Processed foods like crackers and baked goods often contain dangerous trans fats. So you should probably avoid these areas when shopping for healthy fats.

Look in the baking aisle for healthy oils that contain polyunsaturated fat. Remember, oils that contain PUFAs are liquid at room temperature. These healthier liquid oils are often kept on the lowest shelves beneath solid cooking fats. You'll also find nuts and seeds either in the baking area or in the bulk food section of your market.

And of course, visit the fresh fish section of your grocery store to fill up on diet-friendly polyunsaturated fatty foods. A single serving of fish, like salmon or trout, not only provides healthy fat, but is also a good source of protein. A diet that includes protein, good carbs and healthy sources of fat will help your body reach and maintain a healthy weight.


"Basic Nutrition and Digestion" ACE Health Coach Manual American Council on Exercise. 2013.

Medline Plus. Facts About Polyunsaturated Fats. U.S. National Library of Medicine. Accessed: October 20, 2015. https://medlineplus.gov/ency/patientinstructions/000747.htm

Medline Plus. Dietary Fats. U.S. National Library of Medicine. Accessed: October 20, 2015. https://medlineplus.gov/dietaryfats.html

Polyunsaturated Fats. American Heart Association. Accessed: October 20, 2015. http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Polyunsaturated-Fats_UCM_301461_Article.jsp#.ViZ6qxCrTG5

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