February 1, 2022 BY Unbun Foods
It all began in the 1940s when a pioneering American physiologist named Ancel Keys hypothesized the link between dietary fat and heart disease. The idea was, “replace saturated fats with polyunsaturated fats” and lower the risk for cardiovascular events. As his theories evolved and spread, the concept of reducing and eliminating all dietary fat took flight.
By the 1990s, low-fat diets became the overarching ideology. The lack of evidence that it prevented heart disease or promoted fat loss didn’t seem to matter. Physicians promoted it, the food industry saw it for the breathtaking profit-making opportunity that it was, the health media sunk their teeth in, and the modern world became obsessed with fat.
The skinless chicken breast found its time in the spotlight. Butter and margarine became fighting words! Low-fat industrial foods proliferated to fill grocery store shelves. In 1994 we saw the craze go from low to no. First, saturated fat, replaced with polyunsaturated fat, then all dietary fat, replaced with sugar.
As the years went on, a deeper understanding of dietary fats complicated the low-fat agenda. Many scientists began to argue that it was the kind of fat that mattered, not so much the total amount. In the late 1990s Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard School of Public Health, announced that officials had been “dogmatic” about the efficacy of low-fat diets. By 2000, low-fat diets were no longer the scientific consensus for heart health and slowly began to lose their appeal.
Few households in North America made it through this craze unscathed. Arguably, many physicians and consumers are still married to the idea that dietary fat is the leading cause of obesity and heart disease despite high-fat diets like Atkins or the ketogenic diet continually proving otherwise. A diet somewhere in the middle of the two is likely more appropriate for the masses.
Dietary fats are a primary energy source for the body, aid in the absorption of fat-soluble vitamins (A, D, E, and K), maintain the membranes of our cells, make up the structure of the brain and enable its function, maintain body temperature, protect our organs, are necessary for hormone production and fertility, and are truly essential for our survival.
Understanding Dietary Fats
Every food that contains fat has varying percentages of three categories: saturated, monosaturated, and polyunsaturated.
Saturated Fat
Solid at room temperature, butter, coconut oil, lard, all great examples of saturated fat. Because this molecule does not contain any double bonds between their carbon atoms, they are very stable. They are not prone to oxidative damage when exposed to light or heat, making them great for high-temperature cooking.
Saturated fats are categorized by the length of the molecule — long-chain, medium-chain, and short-chain fatty acids. From energy storage to cellular communication, each has an important role to play in the human body.
Monosaturated
This molecule has a single, double bond in its structure, usually making them liquid at room temperature, making them more susceptible to damage from light, oxygen, and heat. Monounsaturated fats are famous for their ability to reduce LDL and triglycerides while increasing HDL. They’ve also been shown to reduce inflammation, lower blood pressure and thus are associated with a reduced incidence of cardiovascular disease.
Olives, olive oil, avocados, and macadamia nuts are some of the best sources of
monounsaturated fat.
Polyunsaturated
This molecule contains multiple double bonds, meaning they are unsaturated at many different points along their molecular chain. This is the most fragile fatty acid, making it highly susceptible to oxidative damage from light and heat and rendering it the poorest choice for cooking.
Polyunsaturated fats are broken down into two categories, Omega-3 and Omega-6 fatty acids. Of which, each breaks down further into an additional six subcategories. As a result, they have very different functions within the body, from the regulation of gene expression to cellular function, fetal development, cardiovascular function, anticoagulation, and more.
Omega-3 Fatty Acids
There are 6 Omega-3 fatty acids, three of which are particularly important.
Alpha Lipoic Acid (ALA), an essential fatty acid (meaning it cannot be made by the body and must be consumed in the diet), is found in liver, kidney, beef, lamb, and in some plant foods like broccoli, tomatoes, and spinach.
Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) are derivatives of ALA, and while humans can make this conversion, it is a very inefficient process. Therefore, it’s vital to obtain adequate EPA and DHA from the diet. Both are found in cold-water fish like salmon, sardines, anchovies, and mackerel, as well as in shellfish like oysters, clams, and mussels.
These Omega-3 fatty acids are anti-inflammatory and essential for the proper development of the brain and eyes. Insufficient levels of both EPA and DHA are associated with many neurological conditions, such as ADHD, schizophrenia, dementia, and Alzheimer’s disease.
Omega-6 Fatty Acids
There are also six different Omega-6 fatty acids, two of which are worth noting.
Arachidonic Acid (ARA) can be produced by our bodies using linoleic acid. It's also found in eggs, chicken, pork, and beef. It is, along with DHA, the most abundant fatty acid in the brain.
Linoleic Acid (LA), on the other hand, cannot be produced by the body. It must be obtained from the diet, thus making it, again, an essential fatty acid. It is found in small and moderate amounts in fruit, vegetables, grains, and meat. However, it is found in enormous quantities in industrially refined oils like safflower, sunflower, soy, corn, cottonseed, and the ubiquitous “vegetable oil”. Unfortunately, more is not better when it comes to linoleic acid. Excess LA is associated with inflammation, gut dysbiosis, psoriasis, eczema, rosacea, depletion of vitamin E and selenium, weight gain, liver disease, diabetes, autoimmune disease, and cancer.
Polyunsaturated fatty acids are prolific in modern food. Cheap, flavourless, and odourless, they are every food manufacturer, restauranteur, and fast-food chains’ dream. After all, for much of the food industry, it isn’t about health as much as it is about the bottom line ($$$).
Getting Your Fats Right
Despite what we were led to believe for the last 50 years, fat is essential for our health. We need saturated, monounsaturated, polyunsaturated, Omega-3, 6, and all the sub fatty acids they include to function optimally.
Balancing Omega-3 and 6 in the diet is the next major unravelling of the dietary fat debacle. Historically, our ancestors consumed Omega-3 to 6 fatty acids in a ratio somewhere between 1:1 and 3:1. At the onset of the industrial revolution, there was a significant shift in the collective diet. Consumption of omega-6 went up at the expense of omega-3. This occurred when the notorious”vegetable oil” was unleashed into the modern food supply.
Since then, we have seen this ratio climb to 10:1 and even 25:1 in some individuals. Americans now get 20% of their calories from a single food source – soybean oil, which means 10% of their daily calories come from Omega-6 fatty acids. This is 10-25X higher than is perceived to be our evolutionary norm. This creates a profoundly inflammatory environment and might very well explain the continued increase in all modern diseases.
Prioritizing Omega-3 and monounsaturated fats, not fearing saturated fatty acids and keeping Omega-6 to a minimum seems consistent with many of the healthiest populations on earth. This revised approach shows the most promising shift towards better cardiovascular and metabolic health.
It can feel overwhelming at times to understand and pivot through the ever-changing nutritional landscape. It doesn’t, however, need to be so complicated. Know your fats, cook at home, avoid items that are highly processed, and focus on nutrient-dense, whole foods that don’t come in a package.