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As it has become clear that dietary fat is not inherently evil and may even promote better health and weight management, the media has explored the macronutrient class in greater depth. Fat is a very non-specific term, referring in the most basic sense to a large group of chemicals that are composed of a string of carbon molecules ending in an acid terminal (fatty acids). The acid-end is like chemical Velcro that attaches to an alcohol group on the molecule glycerol (along with two other fatty acids) in the storage form, called a triglyceride. To burn fat as a calorie source, the fatty acid is cleaved (separated) from the glycerol molecule by enzymes and broken down in a complex series of reactions in the mitochondria. Fat is a very efficient source of energy, which is why there are so many calories in fat as compared to carbohydrates and protein.
However, as alluded to above, fat is not fat. Scientists have discovered a number of fatty acids, but even the most common (palmitic acid, stearic acid, etc.) are not household names. As with celebrity and politics, some fatty acids have gained a limited amount of public awareness due to media exposure. These include essential fatty acids (EFA) and omega-3 fatty acids. Essential fatty acids are used by the body to create hormone-like molecules; these fats cannot be created by the body, but must be consumed in the diet. EFAs include linolenic acid and linoleic acid; many include oleic acid as an essential fatty acid, as humans can only produce marginal amounts on their own and will become deficient in oleic acid if they are deficient in the other essential fatty acids.
Taking A Look At EFAs
Briefly, let’s look at the EFAs, including the conditional EFA oleic acid. These fatty acids fall in the categories of omega-3, omega-6, and omega-9 (omega 3,6 and 9 respectively). The omega designation refers to the first double bond (a type of chemical bond between two carbon atoms in the fatty acid chain) found, counting from the end opposite from the acid.
 Linolenic acid (ALA) is the essential dietary omega-3 fatty acid, found in seed oils and nuts. Flaxseed and hemp are excellent sources of ALA; the acronym ALA refers to the designation alpha linolenic acid, as opposed to gamma-linolenic acid (GLA), which is an omega-6 fatty acid most commonly found in evening primrose oil. Again, ALA cannot be synthesized by the body and must be consumed in the diet. ALA can be incorporated into the membrane of cells, converted into other fatty acids or used for hormone (eicosanoid) production. ALA converts, in part, to EPA and DHA, the omega-3 fatty acids found in fish oil.2
Linoleic acid (LA) is the essential dietary omega-6 fatty acid, found in seed oils but also prevalent in many other food sources.3 People rarely experience a deficiency in omega-6; rather, they tend to have a relative excess of omega-6 to omega-3. Those interested in learning more are directed to read the dated but very informative book Fats That Heal, Fats That Kill by Udo Erasmus.4 Like ALA, LA can be incorporated into cell membranes, converted to other fatty acids (such as the previously mentioned GLA) or used to produce hormone-like molecules. The omega-6 and omega-3 fatty acids compete for some of the same enzyme pathways, so when the balance between omega-6 and omega-3 in the diet is way off, certain conditions are promoted. A diet excessively high in omega-6, particularly arachidonic acid, is suggested to promote inflammation and increase the risk for related conditions.5
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Research and Review 
