Which Unsaturated Fats to Keep Out of Your Diet

Many of us have grown up in an era in which fat has been vilified. We’re accustomed to images of thin, happy people with boundless energy with a cup of fat-free yogurt in hand. For health conscious individuals, it’s practically second nature to reach for low-fat or non-fat milk or choose skinless chicken breast over a well-marbled steak for dinner.

Oh, how times have changed! Whole milk went from 92% of milk consumption in the 1950s to 36% in 2000. As Americans, we’ve been on one wild ride when it’s come to fat recommendations.

Let’s take a look:

In 1910, Americans enjoy butter and lard. Annual per capita consumption is 18 pounds. Lard is the primary cooking fat, 70% of the market share.


In 1911, Proctor & Gamble introduces Crisco, a cheaper, more shelf-stable alternative to butter and lard, made from hydrogenated vegetable oils. Americans unwittingly consume large amounts of harmful trans-fats for the next century.


In 1943, during World War II, the USDA introduces a nutrition guide called the “Basic 7,” which outlines seven food groups necessary to maintain proper nutrition. One of those groups is butter (and margarine). 

  Source: USDA, 1943

Source: USDA, 1943


In 1953, Dr. Ancel Keys, the father of saturated-fat-and-cholesterol-lead-to-heart-disease theory sets the stage for the USDA policy on fats for the next 60 (and counting…) years.

In 1956, the USDA introduces “The 4 Food Groups,” in which butter, margarine, cooking oils, and salad dressings are used to round out meals.

In 1992, the USDA introduces the Food Pyramid, in which fats and oils are relegated to the very top of the pyramid along with sweets and to be “used sparingly.”

  Source: USDA, 1992

Source: USDA, 1992


In 2000, per capita consumption of butter in America is 4.6 pounds, while vegetable oil is 58.3 pounds. (Per capita sugar consumption is over 150 pounds, up from 6.3 pounds in 1822).

In 2005, the USDA introduces “My Pyramid,” in which oil takes a teeny sliver. (If you look closely, there’s a bottle of vegetable oil between the banana and some slices of American cheese).

 Source: USDA, 2005

Source: USDA, 2005


2011 to the present…the USDA recommends “My Plate,” with no mention of fats or oils whatsoever. Current USDA policy recommends minimizing "solid fats," which include saturated and trans-fats, and replacing them with polyunsaturated vegetable oils.

  Source: USDA, 2011

Source: USDA, 2011


It seems like it’s a good time to re-evaluate. Do we even need fat? If so, Why??  Just to name a few functions…

  • Every single one of our cell membranes is made up of fatty acids
  • Over 60% of the brain is composed of fat
  • Fat is a precursor to a number of hormones
  • Fat allows us to absorb and utilize vitamins that can’t dissolve in water
  • Fat is what gives a feeling of satiety after eating (the reason why low-fat diets don’t work)
  • Fat helps to stabilize blood sugar levels

Also, since almost all flavor compounds are fat-soluble, fat is what gives food flavor, allowing us to enjoy eating and get all the nutrients we need!

There are two basic types of fat, saturated and unsaturated. Without getting too deep into the boring details, here’s a breakdown:

Saturated fats are “saturated” with hydrogen atoms, which make their molecular structures very stable—all of the bonds are “used up,” so to speak. These molecules are very straight and as a result, they stack well together, making them solid at room temperature. Butter, coconut oil, and lard are high in saturated fats.

Unsaturated fats have double bonds, and these extra bonds have the potential to receive more hydrogen atoms. The extra bonds eagerly await other atoms to hold onto, making unsaturated fats reactive and unstable. Unsaturated fats are very sensitive to heat and light and become oxidized and rancid under such conditions. The double bonds also create kinks in the molecule, making the molecules difficult to stack together and the oils liquid at room temperature.

These are the fats that I'm choosing to focus on for this month. Stay tuned for more on saturated fats next month..

Monounsaturated fats have one double bond (e.g., olive oil, avocado oil)

Polyunsaturated fats have multiple double bonds—the more double bonds the more unstable and fluid the oil (e.g., corn, soy, safflower, flax seed, nut, and fish oils). The two essential fatty acids, the ones that must be obtained from the diet and that our bodies’ can’t produce on their own, are omega-3 (Ω-3) and omega-6 (Ω-6) fatty acids (named after the positions of the double bonds), both polyunsaturated fats.

The two essential fatty acids work antagonistically in the inflammatory pathway. Ω-6 fatty acids are pro-inflammatory and Ω-3 fatty acids are anti-inflammatory. Acute inflammation is good and absolutely necessary for healing, but many of the most prevalent chronic diseases of modern times, such as cardiovascular disease, arthritis, autoimmune disorders, and cancer are linked to chronic inflammation.

The following is a chart showing the composition of various fats and oils.

  Source: USDA, 2010

Source: USDA, 2010


Most oils high in polyunsaturated fatty acids typically come from seeds, and it’s quite a process to isolate these oils from the seeds. What’s the process, you ask? You ready for it?? Ok, here we go. 


Needless to say, this is quite a toxic process that results in a highly refined, and otherwise fragile oil that has been damaged and oxidized before it even hits the shelf. In fact, a significant portion (0.56% to 4.2%, according to one study) of the oil turns into trans-fats along the way. It is best to stay away from these oils altogether.

Side note: Most of us know now to stay away from trans-fats. Numerous studies point to health problems arising from ingesting even trace amounts of trans-fats. Once touted as a health food and seen as a boon to the processed food industry for making shelf-stable cookies as well as oh-so-flaky pie crusts, partially hydrogenated oils are being removed from the “Generally Recognized As Safe” (GRAS) for consumption list by the FDA.

Polyunsaturated oils are even sensitive to light, and when they’re stored in those ubiquitous clear plastic bottles, sitting on the shelf under bright supermarket lights all day and for days on end, they’re likely to oxidize even further. This is the reason that flax seed and high-quality, cold-pressed seed or nut oils are stored in dark bottles.

The fats that we consume directly correlate with those that compose our bodies’ tissues. (Remember, you are what you eat!) Consuming rancid polyunsaturated fats makes for fragile cell membranes that produce free radicals, which can promote tissue damage, aging, and disease.

But don’t get me wrong—we NEED unsaturated fats! 

However, the typical Western diet, with a Ω-6 to Ω-3 ratio of between 15:1 and 30:1, is far from the optimal 1:1 to 2:1. The high content of corn, soy, and other vegetable oils in processed foods is a major culprit. Also, because these oils are the least expensive, they are the ones used in restaurants. So even if you stay away from processed foods but you eat out with some frequency you are consuming a significant amount of these oils.

To add insult to injury, the fatty acid profile in meat that comes from industrially raised animals (yes, even organic), which are fed a diet of mostly corn and soy, is weighed heavily towards Ω-6 fatty acids. The Ω-6: Ω-3 for grain-fed beef is up to 14:1, compared to 3:1 to 1:1 for their grass-fed counterparts

Ok, so which unsaturated fats should we eat??

It’s fairly easy to get enough monounsaturated and Ω-6 fatty acids. Chances are you're meeting your requirements without even thinking about it. If you eat chicken, eggs, avocados, olives, olive oil, and nuts you’re likely getting enough. 

It is best to get your Ω-3 fatty acids from fish, pastured eggs and meat. Fish particularly high in these beneficial oils include anchovies, sardines, salmon, mackerel, smelt, and black cod. 


Flax, hemp, and chia seeds contain a form of Ω-3 that requires conversion in the body before it’s in a form that is usable, and the rate of conversion can be relatively low, depending on the individual. These sources, however, are satisfactory substitutes if you're allergic to seafood or otherwise staying away from fish.

A note on fish oil supplementation: Most of us have heard the benefits of Ω-3 fatty acids being extolled, and fish oil supplementation is more popular now than ever before. But as discussed earlier, as a polyunsaturated fat, it is very unstable and needs to be treated with the utmost care in processing, shipping, and storing. Many manufacturers of fish oils do not take this care, and the result is oil that is oxidized and rancid before it's even packaged. It is also possible to get too much Ω-3, which is easy to do with supplementation.

As you may have concluded by now, it's best not to subject unsaturated fats to high heat, which means they aren't ideal to cook with. Olive oil, which is slightly more stable due to its high monounsaturated fat content, may be gently heated but is best uncooked. Add it to salads or drizzle some over your food at the end of cooking. (Hint: next month will feature the fats that are better to cook with).


Give it a Try!


The following is a recipe full of healthy unsaturated fats while utilizing the summer bounty. Feel free to substitute the mackerel with sardines, or smelt, which are a bit less fishy. Enjoy!


Grilled Mackerel with Peach-Tomato Salsa

2 fresh, whole mackerel, cleaned, gutted, and divided into 4 filets
¾ tsp salt
½ tsp red chili flakes
ghee for brushing
a drizzle of olive oil

Peach-Tomato Salsa

1 ripe, but firm peach, cut into a small dice
2 Early Girl tomatoes or a handful of cherry/sungold tomatoes, cut into a small dice
zest from 1 lemon
juice from 1 lemon
½ small red onion, minced
¼ cup Kalamata olives
¼ fresh parsley, chopped
½ tsp ground cumin
½ tsp ground coriander
¼ tsp sweet paprika
½ tsp red chili flakes
salt to taste

Sprinkle the mackerel with salt and red chili flakes. Cover and refrigerate while you prepare the salsa, 20-30 minutes.

Combine all of the salsa ingredients, and adjust seasonings, adding salt and more lemon juice as necessary. Salsa should be sweet from the peaches and tomatoes and acidic from the lemon juice. Let stand for at least 10 minutes prior to serving.

Heat the grill to high. Brush the grill with a folded paper towel dipped in a small amount of ghee. Place the mackerel skin side down on the grill until skin gets browned and crispy, about 2 minutes. Flip over and grill on the other side until flesh is just barely opaque, just 30 seconds to 1 minute. Immediately (but carefully) remove to a platter.

(If you don’t feel like firing up the grill, you may also place the mackerel in a broiler-proof pan and broil for a similar amount of time).

If desired, garnish plate with sliced lemons and spoon the salsa over the fish. Drizzle lightly with olive oil. Serve immediately.


mailto: rosie@rosewatercooking.com