Fat in the Human Diet
BY DR. BAYNE FRENCH
As we start to understand the lunacy of standard nutritional advice and begin thinking for ourselves, it seems there is a collective ebb in the deeply ingrained notion that carbs are somehow good for us and a flow in our understanding that significantly limiting them opens doors of health and vitality. But the idea that the consumption of fat is good for us? A tougher prospect, but fortunately one that is the topic of much debate and dialogue. Good fat, bad fat, fat that needs to stay, fat that needs to go—frankly, it’s hard to keep track of it all. In Demystifying Fat, Part 1, in Endurance News 118, we discussed the genesis of the human diet and the role of carbs and fat in that development. We talked about how you can’t trust what is recommended in a pyramid or on a plate. Instead, a study of what humans have eaten throughout our history combined with the DIMADS (Does It Make Any Darn Sense) Test can reveal much about the correct relationship between fat and the human diet. As promised, now we’ll tackle the different types of dietary fat and how they interact with your body.
1. Saturated Fats
Let’s delve into the most contentious fat issue of them all. After decades of pounding the desk, the anti-egg yolk cohort has finally quieted, yet the drumbeat continues on promoting “heart-healthy” omega-6 vegetable oils and maligning saturated fat.
Saturated fat is comprised of fatty acids with only single bonds (no double bonds) linking the carbon atoms together in the chain. Specifically, it is “saturated” with hydrogen atoms. There are short chain, medium chain, and long chain types, some with odd numbers of carbon and others with even. Not many things are subject to more butchered thinking than saturated fat, except maybe that whole grains are good for you (yes, there will be future articles on your cold cereal). We’ve eaten saturated fat forever, as much and as often as we could.
So what’s the problem with saturated fat? In the 1950s Dr. Ancel Keys performed flawed and biased research concluding that saturated fat caused heart disease. The specifics of these unfortunate events are detailed in The Big Fat Surprise by Nina Teicholz. Decades of nutritional policy inexplicably followed, leaving such a mark that “fat is bad” became etched in our psyches.
Another black eye for saturated fat is that it raises cholesterol. For many with antiquated thought processes, elevated cholesterol goes hand in hand with heart disease, America’s greatest killer. But this connection is extremely weak and applies only to oxidized/damaged cholesterol. I have no fear of dietary cholesterol. I raise quail, ducks, and chickens for their oval cholesterol-rich nuggets. Well, a skunk recently killed all my quail and ate their heads. Apparently, quail brain is loaded with fat too (the human brain is 70% fat). The issue of cholesterol will likely be addressed in future articles, but just know there is a deeper story about “good” and “bad” cholesterol involving oxidation, LDL particle number and size, arterial inflammation, etc., that has a far greater contribution to cardiovascular disease than the absolute amount of cholesterol we possess in our blood.
Higher levels of some saturated fats (stearic acid and palmitic acid) in the blood are associated with heart disease. It is critically important, however, to understand that these blood fats do not come from consumed fat, but rather, they are constructed from all carbs. I check blood work on thousands of patients. The carb-eating, fat-avoiders have high blood triglycerides (and a very unfavorable cholesterol profile with lots of small LDL particles). Low carb, high fat eaters very commonly have triglycerides under 100. And very high fat, ketogenic eaters sometimes have triglycerides under 40! Also, what is paramount to realize is that saturated fats cause harm, through inflammation, only when eaten with carbs or when not enough omega-3 fats are consumed. I am very comfortable with the fact that saturated fat does not cause heart disease. This is supported by numerous studies.
Some of the benefits of saturated fat are that it provides structure and function to our cell membranes, is a precursor to hormone production, improves immune function, contains several essential vitamins, and offers an excellent source of energy.
Sources of saturated fats include animal meats and fats (especially red meat), cheese, cream, butter, milk, coconut oil, palm oil, and palm kernel oil. About 50% of the wall of each of our trillions of cells (lipid bilayer) is saturated fat, and over 50% of the fat in breast milk is saturated. A brief study of female chest anatomy should make it pretty clear that we are designed to consume it. The theory that saturated fat is vital in infancy but detrimental in adulthood doesn’t pass the DIMADS test.
2. Monosaturated Fats
This type of fat is comprised of fatty acids with single bonds and one double bond in the chain.
This type of fat is widely agreed to be the most favorable for your health, and it is the primary driver behind many physicians recommending the Mediterranean diet, which is rich in olive oil. Known benefits as outlined from numerous sources include weight loss (especially from the midsection), improved sensitivity to insulin, reduced diabetes risk, reductions in arthritis pain, less LDL oxidation, and reduced risk of blood clots and strokes.
Common sources of healthy monounsaturated fats include olives and olive oil, avocados and avocado oil, various nuts, dairy, and animal fats. The American Heart Association lists only one of the above—olive oil. It lists oil sources from canola, peanut, safflower, and sesame. Although these oils do possess monounsaturated fatty acids, they are also loaded with omega-6 fats (described below) and are obtained with high heat and chemical solvents. I don’t buy them or cook with them. (But a thin layer of canola oil between the toes reduces blistering on long runs.)
3. Polyunsaturated Fats
These are fats with single bonds and more than one double bond in the chain, and they come in two types: omega-6 and omega-3. The difference between omega-6 and omega-3 is one of structure; specifically, the distance the last double bond is from the end. In the body, however, there are numerous biochemical differences between omega-6 and omega-3 fats.
They, like other fats, play critical roles in membrane structure, cellular signaling, immune function, hormonal function, and inflammatory pathways.
Sources of polyunsaturated fats include vegetable oils (3 s’s and 3 c’s: safflower, sunflower, soybean, corn, canola, cottonseed), nuts, seeds, algae, and animals.
As with other fat types, there are numerous polyunsaturated fats. Two of them are unique in that they are “essential,” meaning we cannot produce them in our bodies, they must be consumed. These are the omega-6 linoleic acid (LA) and the omega-3 alpha-linolenic acid (ALA). Other types may be synthesized in the body from these two, and they can also be eaten. These include DHA, EPA, AA, and GLA. There are a couple of things of great importance becoming apparent about these fats. One is the means by which they are extracted, and the other is the ratio of omega-6 to omega-3 in our diet.
Studies of our evolutionary nutrition profile indicate an omega-6 to omega-3 ratio of 1:1, up to 4:1. Given the ubiquity and low cost of omega-6 fats, their delicious nature in deep-fried foods, and their being widely touted as “heart-healthy,” we are certainly not suffering from an omega-6 deficiency. Omega-3s, however, are harder to come by. They are found in wild-caught fish and other seafood, algae, and eggs and meat from animals that ate their native food (picture the opposite of a feedlot cow). Thus the omega-6 to omega-3 ratio in our diets is high, and research supports this as a driver of disease.
LA (linoleic acid) again, is the essential form of omega-6. It is the most widely consumed fat of any kind in America. Vegetable oils are loaded with it, and soybean oil is king. It has been shown to lower LDL cholesterol, and since many physicians still view LDL cholesterol as “bad” cholesterol, they love LA. It is, however, easily damaged, especially when heated, creating oxidized linoleic acid metabolites (OXLAMS), which are oxidized, harmful forms of this fat.
AA (arachidonic acid) is an omega-6 fat made from LA. It is also found in animals, and interestingly is higher in animals not consuming their native foods, like farmed fish and grain-fed livestock. If the ratio of omega-6 to omega-3 is elevated, more AA is produced, which leads to several compounds that promote inflammation.
GLA (gamma-linolenic acid) is a beneficial type of omega-6 found in evening primrose seed oil, borage seed oil, and black currant seed oil. Our bodies produce GLA from LA; however, a deficiency can occur when there is a reduction in the efficiency of the conversion process as people grow older or in the presence of disease or if the consumption of LA is insufficient.
ALA (alpha-linolenic acid) again, is the essential form of omega-3. It is the primary plant source of omega-3, including vegetable oils, hemp, flax, and chia. It is also found in animal products. As mentioned above, vegetable oils contain a lot of LA, which directly interferes with the conversion of ALA to very beneficial EPA and DHA.
EPA and DHA are “semi-essential” in that they are produced from ALA. They are of such critical importance, and their conversion from ALA so easily interrupted, that many authorities view their consumption to be essential to optimal health. They may be consumed from wild animals or from raised animals allowed to consume their native foods. The only plant source of DHA is algae. DHA is considered by many to be one of the most important nutrients of any kind. It makes up 25% of the weight of our brains, 90% of the omega-3 fats in our brains, and half of the membrane of each one of our nerve cells (neurons). The richest source of DHA in all of nature? Breast milk. DHA supplementation has been shown in a double-blinded manner to significantly improve memory and reduce errors.
Trans fats are fats created through the process of hydrogenation. Adding hydrogen to vegetable oil makes these liquid fats solid, which aids their spreadability. In this solid form, they are also easier to transport and store. Hydrogenation was largely driven in the late 1800s by the abundance of soy oil and the shortage of butter. Since the hydrogenated fats are unsaturated, they were advocated as being healthy. But many, many studies have linked the consumption of trans fats to heart disease, diabetes, obesity, dementia, cancer, and sudden death.
In 2006 the FDA required that trans fats be shown on food labels. In 2013 the FDA declared them “not safe to eat.” Foods labeled “trans fat free” may still contain up to 0.5 grams of trans fat per serving. They are present in processed foods and anywhere unstable polyunsaturated vegetable oils are heated.
CLA (Conjugated linoleic acid) is a very interesting naturally occurring trans fat found in grass-fed beef, its dairy products, and other animals that eat their native foods. CLA is a potent antioxidant and confers protection against cancer, heart disease, and diabetes, and it offers benefits on metabolism and weight loss.
If you come to understand this message and the general concepts of the different kinds of fats, you’ll know more than 99% of the people who give out dietary advice, and certainly more than those still beating the “heart-healthy omega-6 vegetable oil” drum! That message is hopefully enjoying its death song. Fat is delicious and nutritious and is vital to optimal human function and health. Low carb eating without higher fat eating is a waste of time, not sustainable, or based on sound nutritional principles. Fat is NOT meant to be consumed with carbohydrate, and “sweet fat” (ice cream, sorry) is the worst. As always, fat sources should be organic. If the fat is from an animal, the animal should have eaten only their native foods. Remember, cows are not grain eaters and chickens are predatory!
Never has this quote, one of my favorites, from the German physicist Max Planck, rung truer than in regard to the dogma of dietary fat:
“A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.” - Max Planck
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