Fat has been demonized by the authorities for contributing to obesity and rise in chronic heart and vascular diseases. This seems intuitive since fat deposit causes obesity and cardiovascular diseases.
The truth is more complex. Like proteins, fats are essential to our bodies. Our brains are mostly fats and cholesterol and saturated fatty acids constitute the majority of the fats found there. Saturated fats constitute the other important structures like the surfactant lining in our lungs and the majority of our cell membranes. Saturated fats protect our livers against alcohol and toxin from medication, and play a key role in the functioning of our white blood cells. To effectively get calcium into our bones, we need at least 50% of fats in our diets to be saturated fats. Fat consumption is a key source of fat-soluble vitamins, like A, D, E, and K, and other essential nutrients. Saturated fats lower blood levels of lipoprotein, a substance strongly linked to heart disease risk.1
The benefits of Omega 3 fatty acids is common knowledge, and tissues rich in saturated fats are found to have better retention of long chain Omega 3 fatty acids. Given the right conditions, fat is an effective long-lasting source of energy.2 Medium chain fatty acids, such as Caprylic acid and Capric acids from coconut oil, are easily converted into ketone bodies and can increase the amount of fat based metabolism.
But this does not mean we can now eat fats in abundance. Fats are still a rich source of calories, a gram of fat gives 9 kcal of energy compared to 4 kcal from carbohydrates. Taken with the right food, fat can be very satiating compared to the same amount of carbohydrates, and this compensates slightly for the higher caloric density.3
Some fats are either harmful to our bodies or can carry harmful substances into our bodies.
Most of the fat we consume today come from vegetable oils dominated by polyunsaturated fatty acids (PUFA), often advertised as “heart healthy”. PUFAs are unstable and easily transformed into harmful trans oils, turned rancid or oxidized when subjected to heat, moisture, and oxygen. These compounds are highly reactive and damaging to our bodies. Rancid and oxidized oils contain free radicals which attack a wide range of tissues, including our cell membranes, red blood cells, and our DNA and RDA. Damages in our blood vessels by such free radicals is thought to be a major cause of fat deposit and clogging of these blood vessels.
Polyunsaturated oils are often hydrogenated into solids as replacements for butter and cream. Hydrogenated oils contain high amounts of trans fats that are toxic to our bodies. Trans fat can be mistaken by our bodies and used in place of naturally occurring variants, and in doing so, they disrupt the cell metabolism. Hydrogenated oils such as margarine or shortening (still commonly used in pastries) are linked to a wide range of diseases, including cancer, cardiovascular diseases, low birth weight, immune system dysfunction, etc.
Some PUFAs, such omega 3 and omega 6, are building blocks of our mitochondria, and are essential to our bodies. However, high ratio omega 6 to omega 3 has been linked to systemic inflammation and various diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases. Studies have found that ratios of 2:1 to 5:1 or below to be beneficial to diseases ranging from colorectal cancer, breast cancer, rheumatoid arthritis, etc. Our modern diets have an omega 6 to omega 3 ratio of between 15 to 50:1 in some estimates, this is driven by the widespread use of omega 6 rich vegetable oils, and the increase in omega 6 and decrease in omega 3 in the meats and eggs from feedlot grain-fed livestock.
Besides saturated fatty acids, and polyunsaturated fatty acids, there are also monounsaturated fatty acids (MUFA). MUFAs tend to be stable, and does not oxidized or go rancid. They tend to be relatively neutral for our health.
Saturated fats are stable and required, and should be consumed.4 Saturated fats are most commonly found in animal fats such as butter, ghee, lard, tallow, duck fat, or with eggs and fatty meats. 5 Tropical oils like coconuts and palm oils are good to plant based sources of saturated fats.
Meats can be fried in their own fats. For instance, grass fed rib eye and strip loin, pork belly and pork collar, fatty fish like salmon, lamb chop, and duck thighs.6 Ghee (clarified butter so it does not contain burnable protein), duck fat, and lard are also good for cooking other things and makes vegetables taste especially good. You can also use coconut oil and palm oil for cooking though not everyone like the strong taste from these oils. For deep frying, use duck fat if you can get it, or peanut oil, which though it contains about 34% of omega 6, and negligible omega 3, is often not processed as heavily as other vegetable oils. Needless to say, peanut oil should be used very sparingly.
Be wary of oils with the large proportion of polyunsaturated fatty acids, in particular, those which are hydrogenated, highly processes, or poorly stored. This includes omega 3 oils and oils in nuts, so it pays to get a good source.
Avoid foods with high level of omega 6. Even if it is not subjected to mishandling, we already have a surplus of omega 6 from our diet and should be actively reducing it. Consider replacing the high omega 6 grain fed beef with the more omega 3 rich grass-fed beef. The same reason and advice apply to chicken and chick eggs. Some farm animals like mutton, lamb, pork and ducks, seems less susceptible to this imbalance though there are still some differences depending on the livestock’ diet.
Common vegetable oils, especially corn, safflower, sunflower, and cottonseed oils, contain more than 50% omega 6 and are often badly damaged by the extraction, processing, and storage. These should not be used.
Canola oil is frequently recommended as the most “heart healthy” oil based on its low saturated fatty acids (5%), high monounsaturated oleic acid (57%), and polyunsaturated fatty acids like omega 6 (23%) and omega 3 (10-15%). Unfortunately, there are some problems associated with canola oil.
Canola oil comes from LEAR (Low Erucic Acid Rapeseed), a variant of rapeseed that’s being bred to eliminate most of the toxic erucic acid. The extraction, deodorization, and processing of canola oil require high heat and pressure, causing most of the polyunsaturated fatty acids, especially the omega 3 fats to become rancid and oxidized. The extraction and processing of canola oil also involve toxic industrial solvent like hexane. Trace amounts of these would be left behind despite subsequent steps to get rid of them.
For these reasons, canola oil should be avoided.
Other great sources of plant-based MUFA and PUFA acids are olive oil, sesame oil, avocado oil, and flax seed oil, and nut oils like macadamia, walnut, and almond oils. These oils are also easily damaged by excessive heat and pressure or improper storage. Except for sesame oil which contains unique antioxidants that are not destroyed by heat, these oils should not be used be cooking. Flax seed oil, in particular, contains a high percentage of omega 3, but it should be noted that most of these are ALA (A-Linolenic Acid). Our bodies need long chain omega 3 fatty acids such as DHA and EPA, and only about 1% of ALA is converted into these.
Seafood is still the best source of DHA and EPA. One caveat, though, fishes tend to pick up pollutants from their environment. Large high-on-the-food-chain fishes like tuna and swordfish tend to accumulate high amounts of heavy metal, especially mercury.
There are many more benefits of fatty acids, but those, and the details of the benefits already cited require more articles. I also left out the discussion on cholesterol in this post, but the general takeaway is that cholesterol is necessary for our bodies and that dietary cholesterol is not something to be concern about. ↩
Insulin which is secreted in response to elevated blood sugar, increases the storage of the excess sugar into muscles as glycogen, and into fat cells as triglyceride. It also shuts down the use of fat as an energy source by inhibiting the release of fats as fatty acids from the fat cells and shutting down fatty acid based metabolism in favor of glucose based energy production. It is very difficult for your body to reduce excess fat as long as your blood sugar is elevated. I believe this is why low carb diets work for quick weight loss, and why high fat and high carb foods like pastry (cakes, donuts, fritters) the worst combination for weight management. ↩
I find high-fat foods (such as butter, lard, and cheese), fat as part of fatty meats, and fats in thick sauces to be satiating, and fats in desserts, snacks, processed foods, and used in stir frying or deep frying, are not. In fact, these foods are often formulated to be ultra-palatable, with combinations of oil, salt, sugar, and artificial flavorings. Making things worse, satiating fats tend to be highly visible, and these are the ones we commonly avoid while being not as careful with the non-satiating sources. ↩
With the usual advice against over consumption. ↩
While the saturated fatty acids in animal fats is seldom an issue, there are 2 other main considerations: 1) the ratio and amount of the accompanying omega 6 and 3, which can be good in grass-fed and pasture raised animal, but unhealthy in feedlot, grain-fed ones; and 2) contaminants such as antibiotics, heavy metals (in fish more than in land based animals), pesticides could accumulate in animal fats. ↩
Some meats such as pork from Iberico are especially prized for their omega 3 rich fats, in the form of Jarmon Iberico. One of my favorite breakfast is fried Iberico pork collar, with eggs fried in the fat from it. ↩
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