A lot of us seem to think anything labeled as "VEGETABLE OIL" is good for us, but it is NOT.
The vegetable oil found in most grocery stores is highly processed soybean oil (can also be highly refined cottonseed, safflower, corn or grapeseed). They are processed under high heat, pressure, industrial solvents (such as hexane).
Note- In the case of soybean oil, the overwhelming majority is grown using genetically modified (GMO) crops that have been heavily sprayed with RoundUp weed killer.
The problem with these oils they are mostly composed of polyunsaturated fats, which leaves them prone to oxidization and free radical production when exposed to heat and light. (read more)
These oils are the most inflammatory inside of our bodies because of their high reactivity to heat and light.
This inflammation is what causes many of our problems such as heart disease, diabetes and other degenerative diseases.
Read what Dr. Lundell has to say about the myths of saturated fats and heart disease
What are the healthy fats to cook with?
Because they are much more stable in cooking conditions and less inflammatory than polyunsaturated oils with cooking.
This is why tropical oils such as palm and coconut oils (and even animal fats such as lard and butter) are best for cooking... they have very little polyunsaturates and are mostly composed of natural saturated fats which are the least reactive to heat/light and therefore the least inflammatory in your body from cooking use.
My Top 3 Choices for Cooking are:
1. Virgin Coconut Oil
2. Olive Oil (for low temperature cooking)
3. Butter (Definitely organic; Grass-fed if possible)
Remember, polyunsaturated fats, aka PUFA, can cause inflammation.
What about Nuts and Seeds?
Nuts and Seeds are high in polyunsaturated fats. It's okay to consume this type of fat as long as it is not processed and kept in its whole food form, such as nuts and seeds. The key to this is to find ones that have not been exposed to high heat. Eat your nuts and seeds in their raw form, so you can avoid the oxidation of polyunsaturated fats that happens through the roasting process. An exception to this is macadamia nuts which can be consumed roasted as they are mostly a monounsaturated fat.
Remember, the light and heat on PUFA's cause inflammation in our bodies.
Fats that are the most stable under heat and light (in order):
(source: Weston A Price: Know your Fats)
1. Saturated: A fatty acid is saturated when all available carbon bonds are occupied by a hydrogen atom. They are highly stable, because all the carbon-atom linkages are filled—or saturated—with hydrogen. This means that they do not normally go rancid, even when heated for cooking purposes. They are straight in form and hence pack together easily, so that they form a solid or semisolid fat at room temperature. Your body makes saturated fatty acids from carbohydrates and they are found in animal fats and tropical oils.
2. Monounsaturated: Monounsaturated fatty acids have one double bond in the form of two carbon atoms double-bonded to each other and, therefore, lack two hydrogen atoms. Your body makes monounsaturated fatty acids from saturated fatty acids and uses them in a number of ways. Monounsaturated fats have a kink or bend at the position of the double bond so that they do not pack together as easily as saturated fats and, therefore, tend to be liquid at room temperature. Like saturated fats, they are relatively stable. They do not go rancid easily and hence can be used in cooking. The monounsaturated fatty acid most commonly found in our food is oleic acid, the main component of olive oil as well as the oils from almonds, pecans, cashews, peanuts and avocados.
3. Polyunsaturated: Polyunsaturated fatty acids have two or more pairs of double bonds and, therefore, lack four or more hydrogen atoms. The two polyunsaturated fatty acids found most frequently in our foods are double unsaturated linoleic acid, with two double bonds—also called omega-6; and triple unsaturated linolenic acid, with three double bonds—also called omega-3. (The omega number indicates the position of the first double bond.) Your body cannot make these fatty acids and hence they are called "essential." We must obtain our essential fatty acids or EFA's from the foods we eat. The polyunsaturated fatty acids have kinks or turns at the position of the double bond and hence do not pack together easily. They are liquid, even when refrigerated. The unpaired electrons at the double bonds makes these oils highly reactive. They go rancid easily, particularly omega-3 linolenic acid, and must be treated with care. Polyunsaturated oils should never be heated or used in cooking. In nature, the polyunsaturated fatty acids are usually found in the cis form, which means that both hydrogen atoms at the double bond are on the same side.