When it comes to choosing a cooking oil, it is best to stick with the fats and oils that have been in the human diet for hundreds of years. Ask yourself, what did my great-grandmother cook with in her kitchen? If she would recognize and use that oil or fat, chances are your body would thrive on it as well.
On the top of my list is butter or ghee. Previously demonized, butter has been vindicated and returned to its place of honor as an exemplary cooking medium and nutritional powerhouse. Butter is a whole-food concentrate of fat-soluble vitamins and contains novel fatty acids such as butyric acid as well as highly beneficial conjugated linoleic acid (CLA) which helps hedge weight gain. Ghee is butter that has been heated in such a way as to remove virtually all of the milk carbohydrate (lactose) leaving a product that is pure butterfat and is thus suitable for people who have a lactose or casein sensitivity. Butter and ghee are very stable fats to cook and bake with and should be used liberally in the diet.
One of my other favorites is coconut oil. From food to medicine to body care, coconut oil is relatively inexpensive, easy to find, and shelf stable for years. Solid at room temperature, coconut oil is a very stable cooking oil suitable for up to 350° in its virgin state and 450° in its more refined form. Virgin coconut oil imparts a delicate coconut flavor to foods while the refined version is far more subtle and can go unnoticed in an array of recipes. High in medium chain triglycerides, coconut oil is brain fuel of the highest caliber. It also contains lauric acid which is a potent anti-microbial suitable for use externally as well as internally.
Olive oil is a nutritional gem. It is replete with rich phytonutrients including phenolic compounds which imbue antioxidant protection to the body. Olive oil can be used for cooking at low temperatures but should never be used for frying; its delicate double bond (being monounsaturated) can easily be broken and become warped with higher heats. Olive oil should be sourced extra virgin and is best used raw as a dressing.
Sesame seed oil is another traditional cooking oil which can be subtle or toasted for a rich asian flavor. Sesame oil is reputed to build platelets in the blood and thus might play an adjunctive therapeutic role in cases of cancer, particularly leukemia. The old nomenclature for this effect was termed vitamin T, which appears to be a placeholder for a group of compounds unique to sesame seeds that have anti-cancer properties (such as sesamolin, sesaminol, and sesamin). Sesame oil also has a gentle laxative effect and is thus useful in mild cases of constipation.
An all purpose cooking oil can be derived by mixing equal parts extra virgin olive oil, unrefined sesame oil, and coconut oil. This is known as Mary’s Oil blend, named after lipid researcher Mary Enig. This oil stays liquid at room temperature and, amazingly, lacks a dominant flavor as the taste of each of the separate oils seemingly cancel each other out.
The best fats for cooking at higher temps are fats rendered from animals such as lard and tallow. These traditionally prized fats are solid at room temperature (by nature of it being a more saturated fat) and resist oxidation. Lard in particular is one of the highest known whole-food sources of vitamin D when rendered from pastured pigs. Similar to humans, pigs convert sunlight into vitamin D which, being a fat-soluble vitamin, gets stored in the fat tissue of the animal. This stands in stark contrast to hydrogenated vegetable oils which are devoid of nutrients, laden with toxic residues from processing, and potentially full of oxidized trans-fats.
Oils to avoid are the industrial seeds oils. They are very high in omega-6 fatty acids, can be pro-inflammatory when consumed in excess, and are highly processed:
Soy and Corn are the most problematic as they are often derived from genetically modified crops. Both soy and corn are also common food allergens. They are also cheap to produce and so processed foods are loaded with them (check labels!) and the majority of restaurants use them, especially in their fryers.
The contrast in the oils discussed here is the story of choosing oils and fats which have been a part of the human diet for millennia and avoiding oils which can only be produced by an industrial process. You are welcome to try squeezing a handful or corn kernels or soybeans to see if you get any oil.
Adapted to by years of evolution and endorsed by the culinary arts, traditional cooking fats and oils should be the mainstay in your kitchen and on your body.