Since the 1960’s it has been believed that consuming fat would make a person fat and was a key player in the development of cardiovascular disease, leading to increased risk of terrible events like heart attacks and strokes.
The dietary guidelines were implemented to decrease all dietary fat, especially natural saturated fats like those in meat and full fat dairy. This in turn, increased our consumption of highly processed vegetable oils and processed carbohydrates as we tried to avoid fat in our diets. These guidelines, however, did not decrease our risk of obesity and cardiovascular disease. We now have learned that this misguided approach to nutrition unfortunately was not founded in solid science.
So, what do we know now? Well, recently the American College of Cardiology has released a publication that stated when looking at all available evidence, including randomized trials and observational studies, it was found that there were no beneficial effects of reducing saturated fat intake on both cardiovascular disease and total mortality (death).
Does this mean that all fat is now good? No, it does not. Let’s take a look at the various forms of dietary fat to get a better understanding of the subject.
Fats are named based on their chemical structure. There are unsaturated fats, saturated fats and trans fats. This next part is a bit of a chemistry lesson, but bear with me, I will try and keep it simple. Feel free to ask questions in the comments! I promise it will be worth it!
All fats are made from carbon chains that are bonded to hydrogen atoms.
When there is only a single bond between all of the carbon atoms, and therefore all the other available bonding sites are taken up by a hydrogen atom, the fat is called saturated. Imagine a long straight dining table. Now imagine all the dining chairs arranged around this straight table are filled by hydrogens. The seats are “saturated” with hydrogens.
The long straight structure allows the molecules to pack together tightly. This tight packing makes them solid at room temperature.
Sometimes, rather than having every available site bound with hydrogen, the carbons bind to each other forming a double bond. This double bond causes the chain to kink, or bend. The double bond leaves room for only one hydrogen (rather than 2). This makes the fatty acid unsaturated, meaning it doesn’t have as many hydrogens bound with it as it could. The bent shape makes it to where the chains cannot fit together as tightly as they can when they are straight. Because of this, unsaturated fats are liquid at room temperature.
Within the unsaturated fat category, there are two main types.
· There are monounsaturated fats where there is only one double bond or kink. These fats are liquid at room temperature, but solidify when refrigerated. Avocados and olive oil are high in monounsaturated fat.
· There are polyunsaturated fats where there are many double bonds or kinks.
These fats are liquid at room temperature and when refrigerated.
Salmon, flaxseeds, chia seeds and walnuts are high in polyunsaturated fat.
Polyunsaturated fats are further classified as
o Omega-6 polyunsaturated fats
o Omega-3 polyunsaturated fats
There are 2 essential fatty acids that the body cannot make on its own that we need to get from our diet, both of them are polyunsaturated.
While the natural polyunsaturated fats that are in whole foods, like those listed above, can contain these important and essential fatty acids, there is a dark side to the polyunsaturated fat story. Remember all of those double bonds and kinks we discussed above? They tend to make the polyunsaturated fats unstable, or more delicate. This makes them highly susceptible to being damaged and oxidized. Heat is the primary culprit, however exposure to light, air and even moisture can be a problem. All fats have a temperature limit which if surpassed, the fat breaks down and deteriorates chemically. This is commonly referred to as it’s smoke point. When this happens, it leads to the development of free radicals which damage cells, proteins and DNA. For polyunsaturated fats, that temperature is quite low and so polyunsaturated fats, as a general rule, should not be cooked with, especially at high temperatures. Additionally, industrialized (highly processed) seed oils such as canola oil, grapeseed oil, soybean oil, cottonseed oil, corn oil, sunflower and safflower seed oil should be completely avoided. The methods of processing to produce these oils includes multiple steps that use harsh chemical solvents deodorizing agents and often heat. These oils are highly inflammatory and are being linked to many health concerns.
That being said, I do not believe that we need to avoid naturally existing polyunsaturated fats like those that are in whole foods such as nuts, seeds, fatty fish and pastured meats as these foods provide our essential fatty acids in their natural forms.
As stated above, saturated fats have all of their binding sites (or seats at the dinner table) taken up by a hydrogen atom and are therefore “saturated.” These fats are solid at room temperature. Lard, tallow, butter and coconut oil are high in saturated fat.
Saturated fats are very stable and they remain that way even at high temperatures. They are not easily oxidized and so are a better choice for cooking.
An easy way to remember this is that unsaturated fats are unstable and saturated fats are stable.
Trans fats only exist in natural foods in very tiny amounts, but are primarily made through the industrial processing of vegetable oils to make them solid at room temperature. Crisco and margarine are examples of this. Trans fats have been found to be extremely harmful to health and have even been out-lawed in some places.
So, what are the take away points?
· Eating fat does not make you fat.
· It no longer looks like reducing saturated fat in the diet reduces cardiovascular disease as previously thought.
· Whole food fats are an essential part of a healthy diet.
· Avoid chemically processed vegetable/seed oils.
· Avoid any hydrogenated oil.
· Try to only obtain polyunsaturated fats from whole food sources likes nuts, seeds and fatty fish.
· Natural saturated fats like lard, tallow, butter, ghee and coconut oil are better for cooking than polyunsaturated and monounsaturated fats, especially at high temperatures.
· Pay attention to smoke points when choosing an oil to cook with.
Do you want to know more about incorporating healthy fats into your daily meals? Consider my Forever Fit Nourished plan!
Forever Yours in Health,
Emalee