Fatty acids can be saturated, monounsaturated, or polyunsaturated. Saturated Fats occur mainly in animal foods and are hard at room temperature. They can be synthesized by the body. These include meat, dairy products, coconut and palm oil. These are converted into LDL-cholesterol (“bad” cholesterol). Saturated fats increase the stickiness of the blood making thrombosis more likely and interfere with the function of essential fatty acids.
Polyunsaturated Fats include corn oil, grape seed oil, safflower oil, sesame oil, soya oil, sunflower oil, wheat germ, fish oil, mixed vegetable oil, and walnut oil. They are usually liquid at room temperature, but will solidify in a fridge. Heating polyunsaturated oil makes it toxic, so these oils should preferably be cold-pressed, stored in a fridge and eaten uncooked. It is easy to add a small amount each day to salads, cooked vegetables or spread on bread. These are high in omega-3 and omega-6 essential fatty acids.
Monounsaturated Fats like olive oil, hazelnut oil, peanut oil, rapeseed oil, almond oil are rich in these types of fats. Monounsaturated fats contain oleic acid (omega-9 fatty acids) that helps to keep arteries limber. These fats are more stable with heat and so are preferred for cooking. Trans Fatty Acids (avoid these) are unsaturated fatty acids with an unusual shape, so the body treats them more like saturated fatty acids. Dairy products, lamb and beef contain small amounts of trans fatty acids. When vegetable oils are artificially hardened to produce margarine trans fatty acids are produced.
Trans fats are most commonly found in biscuits, cakes, pastries (savory and sweet), sausages, crackers and take-away food. High intake of trans fatty acids has been linked to heart disease. Because the trans fatty acids are difficult for the body to metabolize, they accumulate in blood vessels causing blockages. Trans fatty acids can also interfere with the metabolism of essential fatty acids. Some studies suggest that trans fats are worse than saturated fats for health.
Fats are a secondary source of energy used in slow, long duration aerobic exercise. Fats may be either solid or liquid at normal room temperature, depending on their structure and composition. The major fats in foods we eat are triglycerides, phospholipids and cholesterol.