The Big Fat Confusion and Getting Your Fats Right

Cait Mizzi, CFNP

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

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.

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.


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

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.