Fats are molecules made of carbon, hydrogen and oxygen. There are two types of fat - saturated fats and unsaturated fats. The type of fat depends upon the arrangement of the above mentioned atoms in the molecule.
|Type of bonds||Consist of SINGLE bond||Consist of at least 1 DOUBLE bond|
|Recommended consumption||Not more than 10% of total calories per day||Not more than 30% of total calories per day|
|Health Effects||Excessive consumption is not good because of their association with atherosclerosis and heart diseases.||Unsaturated fats are considered good to eat if you are watching your cholesterol. Also high in antioxidants.|
|Cholesterol||Saturated fats increase Low Density Lipoproteins (LDL or bad cholesterol) & Very Low Density Lipoproteins (VLDL's).Sources of bad cholesterol are foods rich in trans fatty acids, refined carbohydrates, such as white sugar, and flour.||Unsaturated fats increase High-Density Lipoprotein (HDL or good cholesterol) and decrease Low Density Lipoproteins (LDL or bad cholesterol). Sources of HDL include onions and Omega-3 fatty acids like flax oil, fish, foods rich in fiber like grains.|
|Commonly found in||Butter, coconut oil, whole milk, meat, peanut, butter, margarine, cheese, vegetable oil, fried foods, & frozen dinners||Avocado, soybean oil, canola oil and olive oil, sunflower oil, fish oils walnuts, flax, & red meats|
|Shelf Life||These are long lasting and do not spoil quickly||These spoil quickly|
|Physical state at room temperature||Solid (Trans Fats & Saturated Fats)||Liquid (Monounsaturated & Polyunsaturated Fats- Omega 3's & 9's)|
|Examples||Hydrogenated Oils, Butter, Processed Meats||Olive Oil, linoleic acid, alpha-linolenic acid|
If the carbon atoms in fat molecules have a single bond between them and as many hydrogen atoms as possible are bonded to the carbon atoms, then it is said to be saturated fat.
The fat is unsaturated fat if the bond between the carbon atoms is a double bond and the molecule can absorb more hydrogen atoms. Or, in other words, unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain.
Types of unsaturated fat
Unsaturated fat is further divided into two types: Mono-unsaturated fat and Poly-unsaturated fat. A fat molecule is mono-unsaturated if it contains one double bond, and poly-unsaturated if it contains more than one double bond.
Health Effects of Saturated vs Unsaturated Fat
Both the types of fat - saturated and unsaturated - are important for daily consumption. It is recommended to take both in a limited quantity. The American Heart Association has determined that Americans should limit their intake of saturated fats to 7% of their total calories in a day. While unsaturated fats can form 30% of the calorie intake.
Saturated fats are needed for the production of hormones, the stabilization of cellular membranes, the padding around organs, and for energy. A deficiency in the consumption of saturated fats can lead to age-related declines in white blood cell function, along with dysfunction of the immune system and even cancer. However, a diet high in saturated fat content can lead to coronory heart diseases and atherosclerosis and increase the chances of stroke.
Unsaturated fats (except trans fats) are usually considered good by dietitians. These fats are known to increase the levels of High Density Lipoprotein and hence decrease the bad cholesterol. Both types of unsaturated fat- mono-unsaturated and poly-unsaturated fats can replace saturated fats in the diet. Substituting saturated fats with unsaturated fats help to lower levels of total cholesterol and LDL cholesterol in the blood. However, intake of unsaturated fats in very high amounts can also increase the risk of coronory heart diseases.
Animal fat tends to be highly saturated with hydrogen, while vegetable fats are unsaturated to varying degrees. However, all foods contain a mixture of saturated and unsaturated fats. For example, poultry contains 30% saturated fat and 70% unsaturated fat.
Foods that contain a high proportion of saturated fat are butter, ghee, coconut oil, cottonseed oil, and palm kernel oil, dairy products (especially cream and cheese), meat, and chocolate. Foods containing unsaturated fats include avocado, nuts, and vegetable oils such as soybean, canola, and olive oil. In reality, many foods contain both saturated and unsaturated fats, but they're described as one or the other depending on which makes up the majority. So, a healthier unsaturated fat such as olive oil contains saturated fats, too.
Chemistry of saturated and unsaturated fats
Saturated and unsaturated fat differ in their chemical structure, specifically the proportion of hydrogen in the fatty acids. All fats contain carbon, hydrogen and a little oxygen to form what are called fatty acids. If the fatty acids contain all the hydrogen possible, they are said to be saturated.
Saturated fatty acids (the building blocks of saturated fat) have no double bonds and this lack of double bond means that there are no gaps in the fatty acid chain; it is packed with CH2 molecules. Unsaturated fatty acids (the building blocks of unsaturated fat), on the other hand, have double bonds and these double bonds break up the string of CHs and create gaps within the fatty acid chain.
If not completely full of hydrogen, then fatty acids are termed unsaturated.
Video explaining the differences