Now that we know a thing or two about healthy eating, the choices are more…um…palatable.  Instead of crisco or lard, we have many plant-based oils to choose from.  But which oils are “good” and which are “bad”?  Let’s try to simplify it, shall we?

Oil
Oil is fat. Any oil that comes from a plant is the fat that is extracted from the plant.  Oils contain 100% fat.  There is no protein, or carbs in oil.

Fats
We need fat in our diets to survive.  They keep our nervous system in check and provide us with “essential fatty acids” which provide fuel for heart and skeletal muscle.  We need fats in our diets to help with vitamin metabolism, hormone balance, and aid with digestion.  You could not survive on a diet of 0% fat.

There are different kinds of fats that make up oils.  The differences have to do with the slightly different chemical compositions.  The three basic fats are saturated, monounsaturated, and polyunsaturated.  These 3 types of fats are present in differing percentages in all oils. For example, olive oil contains 14% saturated fat, 12% polyunsaturated fat, and 74% monounsaturated fat.

It is well accepted that diets high in saturated fats lead to heart disease and cancer, so you want to look for an oil that is low in saturated fats.  Polyunsaturated fats, once thought to be “heart heathy”, are not what we thought they were as they tend to be high in Omega-6 fatty acids (see below).   Monounsaturated fats are the healthiest kinds of fats as they have been linked with lower risk of stroke, heart disease,, and cancer.

Omegas

Some of the polyunsaturated fats contain Omega-3, Omega-6 and Omega-9 fatty acids.  Again, the numbers have to do with the chemical composition in the fat molecule.

Omega-3 fatty acids are very beneficial to you as they help to minimize inflammation.  This translates into combatting and preventing illnesses like  heart disease, breast, and prostate cancer as well as help inflammatory illnesses like rheumatoid arthritis.  Omega-3 fatty acids are not made in the body.  You must get these from your diet.  Salmon, flax seeds and flax oil, olive oil, and walnuts contain Omega-3′s. You can read more about Omega-3′s  here .

Omega-6′s,  need to be supplied by your diet as well.  Omega-6′s are important to your health, but there should be a 5:1 ratio between Omega-6:Omega-3. Unfortunately, Americans eat closer to a 20:1 ratio.  The cheaper oils are very high in Omega-6′s and therefore are the oil of choice for food manufacturers and restaurants. Omega-6′s can cause inflammatory responses in your body.  It is theorized that diabetes, heart disease and cancers are prevalent in the US because of our poor Omega-6:Omega-3 ratio in their diet.  High in Omega 6 are all meats, soybean oil, safflower oil, sunflower oil, cottonseed oil, and corn oil.

Omega 6′s actually compete with Omega-3 in your body, so if you don’t have enough Omega 3, the omega 6 will take over.

Omega-9 fatty acids are produced in your body by the skin glands. Omega-9′s are the most abundant fat found in nature.  If you are not consuming enough Omega-3 and 6, the body will use Omega-9 to compensate, but it is not a perfect substitute, and eventually your health will decline.

Choosing your oil

Some terms you may want to know:

• cold-pressed:  This has to do with how they get the oil out of the plant.  Cold pressed means the plant or seed is squished using pressure and the oil is extracted leaving whatever is not oil behind.  If an oil is not cold-pressed, then chemicals and high heat have been used to force the oil out.  Chemical extraction also strips out the vitamins and anti-oxidants, so it’ not as healthy or as good a quality.
• refined vs unrefined:  Refining means processing. This can be in the form of heating, filtering, or with chemicals. The more refined the oil, usually the higher you can heat it (as with frying)
• virgin vs extra-virgin: extra virgin olive oil (or EVOO as the foodies call it) is produced from the first press of the olives.  It is the purest and best tasting oil.  You should save EVOO for foods where the oil is the star, like when a recipe calls for drizzling the oil over your dish, and is best not heated.   Virgin olive oil is like EVOO  but it has a higher acidity and can be served in hot dishes like soups.
• pure olive oil (or olive oil):  when it says “pure olive oil” or just plain “olive oil”, the oil contains virgin olive oil and pomace.  Pomace is produced from processing the leftovers from the virgin olive oil extraction.  It has a weaker flavor, but can stand up to frying and high heat cooking or baking.  If the bottle is labeled “100% pure olive oil” it is the lowest quality, but can often be a lot less expensive. “Light olive oil” is made from refined or processed olive oil and is the best for frying or high heat.

Oil facts 

• when using oils for dressings choose cold-pressed, unrefined oils to get the best flavor.  Try interesting flavors like avocado or walnut oils.
• avoid heating oils to their “smoke point” (the point where the oils begins to burn).  This means the oil is changing chemically and can be harmful if done often.  it also affects the taste.   Certain oils are better than others for frying.
• choose oils low in saturated fats,  moderate in polyunsaturated and high in monounsaturated.
• store oils in airtight containers in a dark place to prolong life and preserve the antioxidant health benefits.  When oil is packaged, a thin layer of nitrogen is added to the top of the bottle to replace the oxygen.  When the oil is opened and exposed to air, the aging process begins.  Sometimes Vitamin E is added to prolong the oil’s life.  Refined oils high is monounsaturated fats  keep up to a year after opening.  Oils high in polyunsaturated fat keep about 6 months.  Saturated fat oils like coconut and palm have years and years of shelf life.  That’s why the food industry loves them so much!
• try to buy organic oils whenever possible.  Pesticides are “fat soluble” and usually collect in the oil part of the plant.
  

  Vegetable oil can contain anything. In this case it is soybean oil which isn't a vegetable at all, but a legume.