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12 Feb

The Definitive Guide to Fats

Whereas cholesterol usually gets the gold for most demonized nutritional substance, fats undoubtedly take the silver. We recently covered the cholesterol conundrum, and this week it’s time to confront the fervor over fat. Thanks for joining us today. Please make yourselves comfortable.

As you know, I’ve always been a friend to many fats. But the fact remains, ladies and gentlemen, that not all fats are created equal.

A few fats, including but not limited to trans fats, deserve every bit of disparagement they get and then some. However, we feel for those other little guys in the group. Many of them are, assuredly, a good lot, and we’d like to put in a good word for them.

Everyone ready? Servers are coming around with crudite platters as we speak. Let’s begin, shall we?

Fats are compounds of carbon, hydrogen and oxygen atoms that exist in chains of varying lengths, shapes and orders. They’re one of the vital nutrients required by the body for both energy and the construction/maintenance of “structural” elements, such as cell membranes.

Although all fats to some extent contain both saturated and unsaturated fatty acids, they are generally categorized by levels of saturation. Moving on…

The Monounsaturated Fats

Just one type of monounsaturated fat - oleic acid

Biochemically speaking, these fatty acids sport a single double bond in their fatty acid chain. The more double bonds a fatty acid boasts, the more “fluid” it is. They are generally liquid at room temperature.


Monounsaturated fats are found in numerous oils, including olive oil, flaxseed oil, sesame seed oil, sunflower oil, safflower oil, corn oil and peanut oil. Notice that we use the word “found” and not comprise. The fact is, these oils contain varying levels of monounsaturated fat. The rest is a mix of polyunsaturated and saturated. Olive oil, for example, contains about 75% monounsaturated fat, and canola 60%. By the way, these fats are also found in avocados and nuts. They’re granted approval (as much as any fat is in conventional wisdom) as a “healthy fat.”

(Excuse me. May I cut in here please? Yes, I’d like to announce that we will be deconstructing some of this “healthy fat” assertion shortly. Thank you. Carry on.)

Poly in the Cracker? The Polyunsaturated Fats

Just one type of polyunsaturated fat - linoleic acid

Can you guess? Polyunsaturated fats have, yes, more than one double bond in their fatty acid chain. They tend to be liquid even when refrigerated. Their problem is they also tend to go rancid easily, particularly when heated. Yup, it sounds nasty, and you should see it! Free radical damage galore. When we heat them (and we often do), they often become oxidized. We’ve let in the Trojan Horse at that point and opened ourselves up to all kinds of free radical pillaging – everywhere from cell membrane damage to wrinkles to arterial plaque build up.

Polyunsaturated fats are found in grain products, soybeans, peanuts and fish oil. Fish oil and grain products in the same category! Say it isn’t so! (Heightened whispers and shuffling.)

Let’s all take a breath. There’s more to the story.

Enter Essential Fatty Acids!

First off, we call them essential because the body can’t produce them itself and must obtain them from food. We’re talking about omega-3 and omega-6.

Omega-6. It’s important, I fully acknowledge. Omega-6 fatty acids, found in corn and other grains as well grain-fed livestock, play a crucial role in dermal integrity and renal function among other things. But if left unchecked, they run amok, and spur inflammation. Egad! Ratio matters, but we’ll get to that in a minute.

What keeps these guys in check? Why, omega-3s, of course. Ignored for decades by the medical establishment, they’re finally garnering respect, but it’s still not enough in my opinion.


Omega-3s are found primarily in fish, algae, flax and nuts. You also find good portions of them in eggs from chickens that are fed fish or flax meal. And you’ve heard us go on and on about the three forms: ALA (think flax) as well as EPA and DHA (think fish oil). Omega-3s aid circulation by naturally thinning the blood, fight systemic inflammation, support brain function and ease symptoms of depression, anxiety and even ADHD. (Nods of approval)

Now back to the ratio matter. Estimates vary, but experts generally characterize Western diets as anywhere between 10-30 parts omega-6 to 1 part omega-3 (10-30:1). What ratio should we be getting? What did our primal ancestors likely eat? Try 1:1. Although many in the establishment will try to tell you that 4:1 is good enough.

This takes us back to the question of lean meat. If you recall, my reasoning in offering some support for lean meats (in lieu of fattier meats that our ancestors ate, as a number of you reminded me) was the fatty acid ratio of the fat in modern meat. Grain-fed meats are much higher in omega-6 fatty acids and lower in omega-3 than grass-fed meats, but not everyone has access to grass-fed meats. The best way to combat the plethora of omega-6 is to watch your ratios and to consume more omega-3s.

Yes, folks, we’re a long way from healthy here. The sky high ratio of typical Western diets sets us up for inflammation, high blood pressure, blood clots, depressed immune function and sub-optimal brain development and neurological function. Egad, is right.

And so we return to the question of all those “healthy” monounsaturated and polyunsaturated fats. There’s more to the question than the big CW tells you. The omega ratio of “monounsaturated” soybean oil? Anyone, anyone? It’s 7:1. Corn oil? It’s 46:1. (Audible gasps, clutching of pearls, adjustment of jackets)

Olive Oil

So, what about the other oils? What about olive oil? The ratio for olive oil is 3:1, which isn’t great in and of itself. But there’s yet another wrinkle. Olive oil is 75% monounsaturated and 14% saturated, which means that only 11% of it has the polyunsaturated ratio to begin with. In these relatively small amounts, ratio isn’t as much of a concern, particularly when the oil contains so many other good compounds like polyphenols that fight inflammation damage caused, in part, by the problematic ratio. Corn oil, on the other hand, contains only about 25% monounsaturated fat (and 13% saturated). The ratio matters big time here.

The Saturated Fats


Ah, good old saturated fats. You seem so easy in comparison. CW makes you into a monster, but we see you more in the light of King Kong-powerful but sympathetic, misunderstood. You’re among friends here.

Myristic Acid

Before we move on, we can’t forget the chemistry note. Saturated fats have all available carbon bonds paired with hydrogen atoms. I know, not the most interesting, but the important part here is that they’re highly stable. They don’t have the same tendency toward rancidness as polyunsaturated fats, even if heated. This is a good thing.

I’ve been brazen enough to recommend saturated fats, found in animal products and some tropical oils, as part of a healthy diet, and I’ll say it again. Saturated fats serve critical roles in the human body. They make up 1/2 of cell membrane structure. They enhance calcium absorption and immune function. They aid in body’s synthesis of the essential fatty acids and provide a rich source of fat soluble vitamins.

Last but not least, they provide cholesterol. Yes, the human body makes its own anyway, but it all balances out. Can I help that I’ve been won over by its many charms? Naturally occurring substances, natural body processes appeal to me – unlike our next categories.

Trans Fats

Trans Fats

We’ve all heard the story by now. The unnatural chemical modification process that created trans fats made products more shelf stable but has wreaked havoc in the bodies of those who ingest them. (Quick fact: the hydrogenation process changes the position of hydrogen atoms in the fatty acid chain.)

Maleic Acid Hydrogenation

The body doesn’t recognize the transformed fats and, innocent as it is to snack food chemists’ intent, doesn’t know to eliminate it. The trans fats are absorbed through cell membranes, where they initiate general disorder in cell metabolism. Downright unsavory, if you ask me.

Trans fats, banes of our existence that they are, have been associated with inflammation, associated atherosclerosis, diabetes, obesity and immune system dysfunction. And it turns out they’re bad for your profile.

A study out some months ago showed that trans fats caused a “redistribution of fat tissues into the abdomen… even when total dietary calories are controlled.” Kidding about profiles aside, abdominal fat (i.e. apple shaped body) has been associated with the build up of fat around internal organs, which has in turn been associated with a higher risk of heart disease.

Interesterified Fats
“What are these?” you ask. Good question. Insteresterified fats are a new breed of chemically modified fats created to avoid the trans fat label now reviled and even outlawed in some cities. Like trans fats, these fats go through a kind of hydrogenation process along with the associated rearrangement of fat molecules and an enrichment with stearic acid. (Anyone licking their chops yet?) The point is the same as it was with the trans fat poison, er process: it makes the product more shelf stable.

So, this sounds all too familiar, no? Sound like splitting hairs? You got it. (Insert your own expletive.)

My suggestion: if hydrogenated is mentioned anywhere on the label, run like mad.

Now get this. Research is showing that the effects are not just similar to trans fats but worse. Turns out these fats “may raise blood sugar levels even more than trans fats.” Just what we need in this country! The researchers suggest that this new fat actually “alters metabolism in humans.” (General commotion, a few calls to action.)

Ladies and gentlemen, thank you for your generous attention. I say we open the floor for questions and discussion.

ms.Tea, Hulagway, C’est moi!, Slice, Mykl Roventine Flickr Photos (CC)

Further Reading:

The Definitive Guide to Cholesterol

The Definitive Guide to Insulin, Blood Sugar and Type 2 Diabetes

60 in 3: Fat is Bad! Fact of Myth?

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Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. GREAT post Mark!!!!!

    I have a few college buds that this is being sent to now 😉


    Tatsujin wrote on February 12th, 2008
  2. EXCELLENT article….
    so i know this is a dumb question but what is a reommended daily amount of fat and saturated fat?

    sammie wrote on February 12th, 2008
    • For now, the USDA reccomends that 20-35% of calories come from fat, and 10% of calories come from saturated fat. That means 45-77g total fat and <22g saturated fat, but what they didn't take into consideration was beneficial saturated fats like lauric acid (found in coconuts) or stearic acid (found in dark chocolate)

      trajayjay wrote on January 20th, 2013
  3. Loved the article – very informative.

    What is the people’s take on Saturated fats from dairy products (specifically pastuerized stuff?)

    What is a good ratio of o3:o6:saturated:mono:poly? :)

    showbuzz wrote on February 12th, 2008
  4. Fascinating stuff! Very informative and comprehensive. You answered so many questions I’ve had, I can’t think of any more to ask! Well, about fats anyhow. Thanks for the heads up about the interesterified fats – hadn’t even heard of those yet.

    charlotte wrote on February 12th, 2008
  5. n-6 Polyunsaturated vegetable oils – those “lovely” sunflower oils were’ told by Flora are so heart healthy… groan!!!!!!!!

    see this:
    CANCER RESEARCH 41, 3706-371 0, September 1981
    Lipids and Immune Function
    Joseph J. Vitale and Selwyn A Broitman
    Boston University School of Medicine, Mallory Institute of Pathology, Boston, Massachusetts
    There is in vitro and in vivo evidence to suggest that dietary lipids play a role in modulating immune function. A review of the current literature on the interrelationships among dietary lipids, blood cholesterol levels, immunosuppression, and tumorigenesis makes for a very strong argument that (a) immunosuppression may be causally related to lymphoproliferative disorders, as well as to tumorigenesis and (b) diets high in polyunsaturated fat, relative to diets high in saturated fat, are more immunosuppressive and are better promoters of tumori genesis.
    just one quote will do to say enough about the effects of polyunsaturated veg oils:
    Further, there is general agreement that the lowering of serum cholesterol associated with polyunsaturated fat is attributed to the essential unsaturated fatty acids linoleic, linolenic, and arachidonic acids, the same acids which when fed or ingested have been shown to be immunosuppressive


    markus wrote on February 13th, 2008
  6. There are a lot of ‘perfect omega 3 to 6 ratio’ supplements out there these days. It’s a bit of a shame that the makers of these supplements don’t think further than their own product..

    Naomi wrote on February 13th, 2008
  7. So when it all boils down, are these (extra)fats which I include in my lifestyle the best?
    Olives, olive oil, coconut oil, avocado, tehina, flax seeds, hemp seeds, and occas nuts (walnut, pecan, almond, mac, brazil). Then I guess the meat fat from grassfed or org meat and a rare dash of toasted sesame oil in a stir fry!

    sarena wrote on February 13th, 2008
  8. Do you have any thoughts on fractionated oil? Obviously not the healthiest thing in the world since it is highly processed, but is it the same sort of not healthy as trans and interestified fat?

    Katie wrote on February 13th, 2008
  9. Outstanding Article! Eating nuts, fish, and eggs is a great way to get Omega 3. My fav. breakfast, Cooked egg topped with cashew butter. Don’t be afraid of “good” fats, just watch the “calories.”

    Donna wrote on February 13th, 2008
  10. Mark, thank you for this most entertaining and informative look at fats…I learned a lot!

    Dara Chadwick wrote on February 13th, 2008
  11. Great post. I think it’s funny how “fat” has become so hush, hush. It’s ironic that the recommended nutrient intakes call for more of our calories coming from fat than protein. Great job of showing how we still need some fat in our diets. Here’s something I’ve been wondering for a while, but keep forgeting to research though … Does anybody know the difference between virgin and extra virgin olive oil?

    Dan wrote on February 13th, 2008
    • virgin olive oil is just mechanically pressed, to squeeze out the oil, as opposed to using solvents or heat to bring out oils. extra virgin olive oil goes thru some testing to make sure it is of highest quality

      trajayjay wrote on January 20th, 2013
      • Actually, in the US the answer is much simpler than that: nothing. There are absolutely no legally enforced requirements here (though there are, laughably enough, voluntary guidelines) to label olive oil “extra virgin”, as opposed to “virgin”, “olive pomace oil”, or “excess grease from processing equipment, as long as it’s principally derived from olives”. Assessment of olive oil processing and quality is a very big deal in Europe (see International Olive Council), but anything you’ll get in the grocery store here will be varying degrees of garbage they couldn’t sell at a good price there (see Capitalism).

        Jonathan wrote on August 7th, 2014
        • The worst oils will have the best labels and containers.

          Michael wrote on September 26th, 2015
  12. Dan –

    We have a Definitive Guide Post on Oils scheduled for sometime in the next month or so. Stay tuned!

    Aaron wrote on February 13th, 2008
  13. Retail grades in IOOC member nations
    As IOOC standards are complex, the labels in stores (except in the U.S.) clearly show an oil’s grade:

    Extra-virgin olive oil comes from cold pressing of the olives, contains no more than 0.8% acidity, and is judged to have a superior taste. There can be no refined oil in extra-virgin olive oil.
    Virgin olive oil has an acidity less than 2%, and judged to have a good taste. There can be no refined oil in virgin olive oil.
    Pure olive oil. Oils labeled as Pure olive oil or Olive oil are usually a blend of refined olive oil and one of the above two categories of virgin olive oil.
    Olive oil is a blend of virgin oil and refined oil, containing no more than 1.5% acidity. It commonly lacks a strong flavor.
    Olive-pomace oil is a blend of refined pomace olive oil and possibly some virgin oil. It is fit for consumption, but it may not be called olive oil. Olive-pomace oil is rarely found in a grocery store; it is often used for certain kinds of cooking in restaurants.
    Lampante oil is olive oil not used for consumption; lampante comes from olive oil’s ancient use as fuel in oil-burning lamps. Lampante oil is mostly used in the industrial market.

    [edit] Label wording
    Olive oil vendors choose the wording on their labels very carefully.

    “100% Pure Olive Oil” is often the lowest quality available in a retail store: better grades would have “virgin” on the label.
    “Made from refined olive oils” suggests that the essence was captured, but in fact means that the taste and acidity were chemically produced.
    “Light olive oil” actually means refined olive oil, not a lower fat content. All olive oil has 120 calories per tablespoon (34 J/ml).
    “From hand-picked olives” may indicate that the oil is of better quality, since producers harvesting olives by mechanical methods are inclined to leave olives to over-ripen in order to increase yield.
    “First cold press” means that the oil in bottles with this label is the first oil that came from the first press of the olives. The word cold is important because if heat is used, the olive oil’s chemistry is changed.
    “Bottled in Italy” or “Packed in Italy” does not necessarily mean that the olive oil originated in Italy. Back or side labels indicate the origin of the olive oil which is often a mixture of oils from several nations[6].

    [edit] Retail grades in the United States
    Most of the governments in the world are members of the International Olive Oil Council, which requires member governments to promulgate laws making olive oil labels conform to the IOOC standards.

    The United States is the only major oil-producing or oil-consuming country which is not a member of the IOOC, and therefore, the retail grades listed above have no legal meaning in the United States. The U.S. Department of Agriculture (USDA), which controls this aspect of labeling, currently lists four grades of olive oil: “Fancy”, “Choice”, “Standard”, and “Substandard”. These were established in 1948. [7] The grades are based on acidity, absence of defects, odor and flavor. While the USDA is considering adopting labeling rules that parallel the international standards, until they do so, terms such as “extra virgin” may be applied to any grade of oil, making the term of dubious usefulness.

    Stu wrote on February 15th, 2008
  14. After reading this, I have a question. When cooking, does it make more sense to use saturated fat, such as butter, instead of oil?

    Because, according to the definitive guide to fats, mono and poly unsaturated fats found in oil are more likely to form free radicals when used to fry something on a skillet or bake something in the oven.

    VAS wrote on February 15th, 2008
    • Yes, actually, using a saturated fat like coconut oil is safer. The double bonds in poly fats are more apt to form trans fats when heated to high. Monounsaturated fats like olive, peanut, and canola* can tolerate moderate temperatures on the stove.

      *Personally, I don’t recommend canola oil, i’ve heard some pretty nasty things about it, it has to go thru a lot of processing and chemical extraction to detoxify it to humans. And free radicals form. Never again will I buy canola oil

      trajayjay wrote on January 20th, 2013
  15. Excellent post! Thanks!

    VAS yes! you should only use ploys for low heat cooking. I only add it at the end. I use coconut oil, butter, bacon fat, etc for cooking. Coconut oil is the best.

    All commercial oils, in my opinion, should be avoided as they are heat processed. These include soy, corn and cannola.

    Cindy Moore wrote on February 16th, 2008
  16. Great article and thoroughly researched. I especially appreciate that you added some chemical drawings for an increased understanding.

    Jason wrote on February 16th, 2008
  17. What exactly is “low heat” and “high heat” cooking?

    I use a tablespoon of olive oil when I bake chicken. It usually cooks @ 400 degrees for 30 to 40 minutes.

    Barry wrote on April 2nd, 2008
  18. “What exactly is “low heat” and “high heat” cooking?”

    Barry, truthfully, I don’t know the temps that are safe. I don’t use any of those when I cook. I do like olive oil, but don’t use it much. I use coconut oil, butter, bacon grease (nitrate free bacon), etc for all cooking. If I make something that calls for olive oil I add it at the end of cooking, with the heat turned down or off. I don’t use it for baking.

    I have read that if the oil smokes it’s damaged, so it should be thrown out. I can’t afford to be throwing food away, so I don’t use oils that smoke easily. Saturated fats are much more stable than polyunsaturated fats so are better for cooking.

    I think tho, that the biggest problem is stove top cooking, where the temps (I think) are higher. I’ve seen recipes to bake fish at 350, so I guess that’s safe at least.

    Here’s a little list I found:

    Here are a few examples of oils and their smoke points (get your thermometers ready!):
    Sunflower oil – 440F
    Canola oil – 400F
    Butter – 350F
    Extra virgin olive oil – 320F


    Cindy Moore wrote on April 2nd, 2008
  19. How much fat to consume while in ketosis?
    And also from Type 2 diabetic point of view?

    sandra wrote on July 13th, 2008
  20. What about Dairy products?

    Good or Bad?

    Louann wrote on February 2nd, 2009
    • Bad! Paleolithic man had no access to milk since animals were not domesticated and would have eaten him before he was able to steal the milk. The human genome suffers from lactose intolerance because it has yet to evolve to accept it.

      PJT13 wrote on July 15th, 2010
      • Good! The “human genome” only suffers from lactose intolerance because it’s drinking pasteurized/homogenized milk from cows that are fed corn. That’s the bad part. Raw milk is not pasteurized/homogenized so the enzyme lactase (which digests the lactose) hasn’t been destroyed by heat, which means that those who are lactose intolerant can usually drink it. Also, raw milk is typically from cows that are grass-fed (which is a cow’s food of choice)so the milk has an abundance of nutrition – proteins, carbs, fats, vitamins, minerals, enzymes. Pasteurized/homogenized milk is denatured in the process & Vits A & D are added back, but in a synthetic form.
        Real milk – raw – the way nature intended should be a part of everybody’s diet.

        Linda wrote on January 23rd, 2011
      • how can we eat butter if we can not drink milk?

        Wendie McConnell wrote on July 28th, 2011
        • Being lactose sensitive myself, I was very happy to learn that cheese and butter have much lower lactose concentration than milk. During fermentation, bacteria take care of consuming most of that yummy sugar leaving behind a product that is nearly lactose free. This only applies to cultured butter though. Traditional butter is still low on lactose, but for a different reason: As the milk fat is separated from water, a big part of the lactose is left behind.

          El Groko wrote on August 28th, 2011
      • what about mommy’s milk?

        trajayjay wrote on January 20th, 2013
  21. Very nice article. I’m not completely elucidated yet. I would love to see two things to help me get organized about my eating efforts: 1. a chart-view summary of fat types organized by priority of healthfulness and providing examples of food types per fat; and 2. perhaps a separate post altogether on oil types (walnut, olive, grapeseed, vegetable, etc.) and a similar chart-view summary. Those would be absolutely priceless…

    Mark? 😉

    asfdasdf wrote on February 4th, 2009
  22. *high five*

    Excellent article, as always. I’m a bit of an idiot but that made perfect sense to me and I’ll be using it to inform my eating habits from now on.

    Ross wrote on February 12th, 2009
  23. You are so brave to recommend saturated fats. You know what works and aren’t afraid of the establishment. Way to go!
    I live on saturated fats.

    curiousfarmer wrote on February 22nd, 2009
  24. Great article and very informative.

    We need to break free from junk science, and realize that FOOD is good for us, where man made stuff is not. Fat, carbs, and protein are essential for us to survive.

    I wish that the “establishment” would quit contradicting themselves.

    It “appears” (strong emphasis on “appears”)that all the flip-flopping is just a mere a coincident to a next release of diets, food systems, books, and talk show appearances.

    All well intended and in our best interest of course.

    DKF wrote on May 14th, 2009

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