Fats are also known as lipids. The old days of knowing fats as unhealthy are all but gone as we know some are essential to health. But yes, some are still unhealthy.
Lipids occur in the body as fats, phospholipids and steroids. The most commonly known fats are saturated, polyunsaturated and mono-unsaturated. The structure of these fatsare very similar but the slight differences have big physiological impacts.
Saturated fats – these can be identified quite easily as they exist as a solid at room temperature. There is an artificial saturated fat known as trans fats which is formed through a process called hydrogenation. Basically, is takes a non-saturated fat and adds hydrogen to it which removes the double bonds from its structure which makes it solid at room temperature. This is commonly used in making spreads.These are not health.
Saying that saturated fats are bad for you is not strictly true as it is needed to keeping cell membranes healthy and is involved in hormone synthesis. So, a little is very good for you but over doing it can rise cholesterol.
Unsaturated fats – these can be found in many plant sources like nuts, seeds and cold pressed oil. They are also found in dark leafy greens and in legumes but to a lesser extent.
Polyunsaturated fats – these exist as a liquid at room temperature and when slightly chilled. These are found in nuts, vegetables and some animal products like eggs and meat also fish. Although these are good fats it is not a clever idea to cook with them because at high temperatures as it degrades it and creates free-radicals that are harmful to the body.
Mono-unsaturated fats – Thanks to their structure it is best to cook with these as they are more stable. The function of these fatsare similar to polyunsaturated fats but they also increase the production of high density lipoproteins (HDL) which collect cholesterol from the tissues of the body and brings it to the liver to be exposed of. These are found in olive oil, olives, avocado, nuts and seeds.