Figure 1. Notice that around each carbon (C) there are a total or four lines (chemical bonds). That is because carbon likes to be surrounded by four electrons (shared electrons make up the bonds). Each hydrogen (H) likes to be surrounded by one electron and each oxygen (O) likes to be surrounded by six electrons (two are shown as bonds and the other four should be shown as dots around the oxygen but are not shown here). A single line represents a single bond. A double line represents a double bond, which basically means that there is not a hydrogen there so the electrons form another bond with the closest element.
Saturated Fats (mmm, my favorite)
Saturated fats are important. Sorry but it’s true. I know it sucks to think that you could eat butter and eat red meat every now and then but hear me out. An article from the American Journal of Clinical Nutrition reviews the all too famous Framingham study, which followed thousands of people for decades, and stated that it shows no good evidence that saturated fat causes heart disease. Oops, American Heart Association! In fact, saturated fats can enhance HDL levels (you know, the good cholesterol) and is actually preferred by the heart for energy. Oops again AHA! Maybe there was a secret culprit in that silly study by Ancel Keys back in the 1960’s that said we should only eat unsaturated fats that you didn’t notice (like trans fats maybe?) I could go on for pages about the importance of saturated fats but I’ll save that for another article.
Notice on the saturated fat molecule shown above that there are no double bonds between the carbons. Each carbon in the carbon chain (the string of carbons with H’s) has as many hydrogens as it can bond to without exceeding the four electrons carbon likes around it. That is what we call “saturation.” No more hydrogens can be added.
This makes the saturated fat very stable. It is saturated with hydrogens and a bond with hydrogen is more stable than a double bond with another carbon. This means that under reactive conditions, like heat, there will be less change in the molecule. Change could be in the form of oxidation (yes the opposite of anti-oxidants are oxidants). So saturated fats are better to cook with, especially at high temperatures because less oxidation occurs! Even without high temperatures, oxidation can occur from sunlight or oxygen and saturated fats stand up to these tests with superiority as well.
Notice on the unsaturated fat molecule shown above that there is a double bond between the 3rd and 4th carbon from the right. Well this double bond can be in any number of places on a mono-unsaturated fat (meaning there is only one double bond). Where the double bond is will determine its name. In a poly unsaturated fat there will be two or more double bonds and where those are will decide its name as well.
Since unsaturated fats have those more reactive double bonds, they are actually more likely to change oroxidize during cooking. Oxidation is what causes damage to our arteries, increases the aging process, and stresses our bodies, causing us to need to eat more anti-oxidants. Oops again AHA! Did you consider that people might heat those oils? The more unsaturated an oil is, the more likely it is to get damaged from heat, light, or air, and it may even form trans fatty acids.
This is not to say you shouldn’t eat unsaturated fats. We need them too. There are actually some very important essential fatty acids that are unsaturated, like the so important DHA and EPA. “Essential,” means our body cannot make them so we have to eat them. Ultimately we want a good balance of these types of fats. The important thing to remember about unsaturated fats is that they are more susceptible to being oxidized from heat and sunlight, so should be eaten cold or cooked with very low heat.
Figure 2. Example of Cis and Trans configuration for fat molecules
Trans Fats – A History of Profit
Trans fats (figure 2) have two hydrogens across from each other surrounding the double bond. Trans just means “across,” from each other in the unsaturated bond in this term. What? Trans fats are unsaturated? Yes, they are. Look at the double bond shown in the picture. There is room for two more hydrogens around that bond. This does not occur in nature, meaning if you grab some nuts to munch on or slice up an avocado (both are rich in unsaturated fats) there will be no trans fats. Trans fats occur when scientists sloppily blast hydrogens into unsaturated fats.
Why would a scientist do something like that? Well, ironically, right around the time of the was famous now increasing infamous Ancel Keys’ study suggesting that saturated fats were unhealthy, there were a lot of food companies that were making a lot of money off of industrialized foods. Food industrialization was all the rage (who didn’t want those fancy new packaged foods?) and vegetable oils were cheaper for food manufacturers to use. The problem was that they were often unsaturated which meant they went bad faster than the commonly used animal fats of that day.
Food manufacturers wanted to make foods that would be shelf stable. You know, like those snack cakes that can sit until the end of time and not go stale? And they wanted to do it with cheap oils to maximize profit. It’s quite interesting how that study that Ancel Keys did on saturated fats was not solely with saturated fats. There were trans fats mixed in. This is something he mentioned but did not expand upon, to the detriment of many. The study showed a possibility for the increase in heart disease and saturated fats were the scape goat. Great news for the food manufacturers. Bad news for everyone eating trans fats.