Now, we know our cholesterol number does not determine our health. The emphasis should be placed on the amount of good and bad fats—we need to know what the difference is between good and bad cholesterol. Good cholesterol (HDL) is needed to keep our vessels and skin supple and retain flexibility to absorb stress on the body. The differences between good and bad fats or cholesterol are the amount of saturated and unsaturated components. The more unsaturated a fat is, the better it is for you. We need some saturated fats in our diet, but they should be limited.
Unsaturated fats are primarily derived from fish and plants, such as nuts. Unsaturated fats are liquid at room temperature and usually have a low smoking point. This means the oil starts to burn and become unhealthy at temperatures beginning at 225 F. Unsaturated fats vary in the content of omega 3s, which are important for brain function—including mood. So, we need unsaturated fats high in omega 3s, like cod liver and flax seed oils.
Saturated fats are derived mainly from animal and dairy products and some plant sources, like palm and coconut. Saturated fats are usually low in omega 3s, which is why we want to limit them—they contain more inflammatory components like omega 6 and 9. Saturated fats are solid at room temperature (e.g., lard) and are stable for cooking using high heat. Included as bad fats are trans fats—hydrogenated or partially hydrogenated oils are currently being eliminated from most food products. My recommendation for cooking oils at low heat (up to 350 F) is olive oil—for higher heats use macadamia or grape seed oil.
Canola oil is genetically modified and not recommended. The worst fat, in my opinion, is the currently fashionable coconut oil. It is almost entirely saturated, contains only trace amounts of omega 3s and has a low smoking point. Other highly refined oils, such as soybean, corn and vegetable oils are also not recommended.