What Are Trans Fats? Are There Cis Fats?

(Last Updated On: August 4, 2020)

What Are Trans Fats?

What Are Trans Fats?

You’ve probably abstractly heard of trans fats as basically the food boogeyman. But nobody ever really sits down to explain or talk about why trans fats are bad beyond something related to cholesterol. Which, to be fair, is probably all we need to know or care about. “Thing bad, don’t do thing; thing good, do thing.” Throw in some moderation while you’re at it. But what are trans fats, really?

Why Are They Called Trans Fats?

Well you probably figured that trans fat was short for something, particularly trans-unsaturated fatty acid or just trans fatty acid. Depends on whether or not it’s saturated. 

What does saturated mean? Glad you asked, it’s an organic chemistry thing. A key trait of fats are long hydrocarbon chains, which just means chains of carbon with hydrogens attached to them. One of carbon’s fun chemistry traits is consistently making 4 bonds. Which makes a chain of hydrocarbons a bunch of carbons attached to each other in a line, meaning each carbon is attached to two other carbons. The remaining bonds (2) are filled in with hydrogen, except the end, which has three.

You can end up with carbons in the chain not bonded to 2 hydrogens, instead they might be bound to just the 2 other carbons and 1 hydrogen. In that case, you get a double bond, because carbon needs to make 4 bonds or it has a certified not good time. Basically that means the carbon has bonded twice to another thing, which is carbon in the chain (hydrogen doesn’t do double bonds). When this happens, the hydrocarbon chain is unsaturated. A chain where there are no double bonds is saturated. 

Organic molecules can also be cis or trans, which dictates what side things are on. When you see those diagrams with all those squiggly lines, there’s actually a reason. You can have two (important) parts of a molecule be on the “same side” as each other. This molecule is designated “cis,” while a molecule with its parts on the opposing side is “trans.” 

What About Cis Fats?

Cis fats do exist, and most unsaturated fats do exist in their cis forms. Typically, they do the opposite of what trans fats do to you, namely increasing levels of beneficial types of cholesterol while decreasing levels of the bad kind. It’s not uncommon for us to turn cis fats into trans fats by cramming them full of hydrocarbons–turning them into saturated trans fats.

Why? Well we can look at oleic and elaidic acid. They’re made up of the exact same atoms, they share a chemical formula. Oleic acid is in its cis form, while elaidic acid is in its trans form. Maybe you’d think they’d be astoundingly similar, since they share the same formula. But judging by the fact that they have different names, you’ve likely figured out that they are more likely astoundingly different.

Oleic acid melts at a far lower temperature than elaidic acid. In fact, oleic acid is a liquid at room temperature, while elaidic acid is not. Generally speaking, that’s why the food industry prefers trans fats. Because saturated trans fats are basically the molecular equivalent of straight lines, they can pack themselves a lot closer together–making food more dense, but also making it less likely to melt. Better packed molecules tend to melt at higher temperatures. 

As a result, trans fats tend to last longer than their cis counterparts. They’re also generally easier to store, as they won’t melt at room temperature. That’s why you see so many trans fats being artificially created in comparison to their cis counterparts.

Alright, so What Do Trans Fats Do?

Well, before we get super into it, yes, they’re absolutely terrible for you. So bad, that the American Food and Drug Administration gave corporations until 2018 (in about 2015) to force food manufacturers to stop artificially making trans fats. Unfortunately for our bodies, they weren’t able to get them all, with the date of compliance extended to 2020 and 2021 for some artificial trans fats. Thanks, food industry. 

The World Health Organization has also since launched an anti-trans-fat campaign in 2018.

While trans fats can occur naturally, they don’t typically do so in very large amounts. Normally you find them in things like beef and lamb. There hasn’t been a lot of research on these trans fats, probably because the artificial ones are overshadowing them.

We know that there are good and bad types of cholesterol, the bad type being low-density lipoprotein (LDL) while the good kind is referred to as high-density lipoprotein (HDL). The latter takes excess cholesterol back to your liver, while the former is the kind that clogs up your arteries. The good old artery cement.

Trans fats generally raise LDL levels while lowering HDL levels. Meaning it makes it easier to clog your arteries, while also making it harder for your body to clear out that cement. This cement can form more significant clots that jam your heart up, which is why cholesterol is linked to heart attacks and other cardiac issues. 

While more research needs to be done linking trans fats to cancer and maybe diabetes, we know that they can damage your blood vessels and are already terrible for your heart. So cutting back on those will probably do us a healthy favor.

We did fats by food and chemistry, see if you can do them by movies here.

About the Author:

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Kyler is a content writer at Sporcle living in Seattle, and is currently studying at the University of Washington School of Law. He's been writing for Sporcle since 2019; sometimes the blog is an excellent platform to answer random personal questions he has about the world. Most of his free time is spent drinking black coffee like water.