Fats are organic molecules made up of carbon and hydrogen elements joined together in long groups called hydrocarbons. The arrangement of these hydrocarbon chains, and their interaction with each other, determines fat type.
The simplest unit of fat is the fatty acid. Fatty acids are composed of simple hydrocarbon chains with special chemical groups at each end: a methyl group on one end and a carboxylic acid group at the other. There are two general types of fatty acids, based on the level of saturation (the number of hydrogens associated with each carbon along the hydrocarbon chain): saturated fatty acids and unsaturated fatty acids.
Unsaturated fatty acids can be broken down into monounsaturated fatty acids (in which only one carbon is unsaturated) and polyunsaturated fatty acids (in which more than one carbon is unsaturated).
The often-discussed omega-3 and omega-6 fats are both polyunsaturated fatty acids; the specific locations of unsaturated carbons along the fatty acid chain give them their name and different functions.
Fatty acids can be joined together to form what are called triglycerides. As the name implies, three fatty acids join together with a glycerol molecule to make up a triglyceride. Triglycerides are the major form of fat in the diet, and the major storage form of fat found in the body.
Dietary fat has six major roles:
Most dietary fat comes in the form of triglycerides. Triglycerides contain three fatty acids attached to a glycerol backbone. So different fatty acids can join up to form various permutations of triglycerides.
In other words, most dietary fat sources are made up of some combination of saturated, polyunsaturated, and monounsaturated fatty acids. For example, while most people consider eggs and red meat to be foods rich in saturated fat, eggs actually contain more monounsaturated fatty acids than saturated fatty acids. Indeed, 39% of the fat in eggs is saturated, while 43% comes from monounsaturated fat, and 18% from polyunsaturated fat. Beef contains 55% saturated fat, 40% monounsaturated fat, and 4% polyunsaturated fat.
Overall health is determined by the balance of fatty acids consumed. For example, saturated fat appears to be fine when refined carbohydrate intake is low and when a healthy intake of unsaturated fat is also present. Just don’t combine a diet low in unsaturated fat with one high in saturated fat, sugar, and refined carbohydrates (which, unfortunately, characterizes much of our modern North American diet).
Food sources of fat include the following:
Some of our essential vitamins are fat-soluble, which means you need to eat some dietary fat in order for them to be properly absorbed into the body. A fat deficiency could in turn cause a deficiency in vitamins A, D, E and K.
A deficiency of essential fatty acids – Omega 3 and Omega 6 – could cause cognitive/brain development problems, vision impairment, skin problems, and delayed healing. There are also some links between Omega 3 fatty acids and mental health, so a fatty acid deficiency could lead to depression or other negative feelings.
However, your individual response could be different. If you suspect a health problem or deficiency in certain nutrients, please see your primary health care provider (doctor, naturopath, etc). They can help unravel the complexity of your physiology.
Note: Most Americans are deficient in Omega 3 fatty acids.
Dietary fats – even healthy fats – tend to be highly caloric, so an abundance of fat-dense foods could lead to weight gain.
Eating a surplus of saturated fat could cause diabetes, high cholesterol, heart disease, and even certain types of cancer.
However, your individual response could be different. If you suspect a health problem or an excess of certain nutrients, please see your primary health care provider (doctor, naturopath, etc). They can help unravel the complexity of your physiology.
Note: Trans fats also need to be mentioned here. Trans fats are created through hydrogenation and are quite dangerous. A diet high in trans fats has been associated with a higher risk of alzheimer’s disease and lymphoma, suppression of the excretion of bile acids, increased liver cholesterol synthesis, competition for essential fat uptake, and exaggerated essential fatty acid deficiency. Even a single meal with a high trans fat content can diminish blood vessel function and elasticity, which can contribute to the progression of heart disease. But, when consuming a diet based on natural, unprocessed, whole foods, cumulating high amounts of harmful trans fat is nearly impossible.
For recipes rich in fats, check out any of the Encyclopedia of Food entires for food items listed above!
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Fats are made up of carbon and hydrogen elements joined together in long groups called hydrocarbons. The simplest unit of fat is the fatty acid, of which there are two types: saturated and unsaturated. Dietary fat plays a number of important roles in the body: it provides energy, helps manufacture and balance hormones, forms our cell membranes, brains, and nervous systems, and helps transport certain vitamins. It also provides two essential fatty acids that the body can’t make: linoleic acid (an omega-6 fatty acid), and linolenic acid (an omega-3 fatty acid). Dietary sources of fat include nuts, seeds, coconut, avocado, olives, and egg yolks.