Saturated Fat, Unsaturated Fat, And Trans- Fat - What Is The Difference?

Doctors all over the world, and especially in the United States, by and large have become obsessed with fat — and, more specifically, the idea that it's universally bad. Body fat is bad. Dietary fat is bad. Unsaturated fat is also bad, but saturated fat is worse, and trans-fat is worst of all. Or so most of us are told.

What's actually going on? If you're not sure what the differences between different types of fat are, that's something worth learning more about.

What's the Difference Between the Different Kinds of Fat?

On a purely chemical basis, the difference between the three best-known kinds of fat has to do with how predictably the body can process them.

Every molecule of fat can be drawn with a “backbone” of a string of carbon atoms. In saturated fat, each carbon atom in the molecule bonds to one carbon atom on either side, like this:

C – C – C – C – C – C

Since carbon atoms can form up to four bonds altogether, in a saturated fat, every carbon in the middle of the molecule bonds to two other atoms or ions and the carbons on the ends can bond to three. When a fat molecule is saturated, it doesn't have any room for unpredictability. The body has to process saturated fat the same way each and every time, and it is a lot more likely for the process to go wrong.

What Is Unsaturated Fat?

In unsaturated fat, at least one pair of carbon atoms is joined with a double bond, which looks something like this:

C = C – C – C – C – C

Carbon atoms, however, can form up to four bonds. This means that the human body can process unsaturated fat in many different ways, making sure that it is burned as fuel rather than converted into the forms of LDL cholesterol (contrary to popular belief, not all LDL cholesterol is actually harmful) that can harden and stiffen the linings of blood vessels throughout the body. That is why unsaturated fat is generally considered to be healthier.

What Is Trans- Fat?

In trans- fat, the carbon atoms don't line in a nice, neat row. They instead gather into a configuration that looks something like a broken arrow with a barb on one end. Here's a better idea of what that's like:

C

/

C – C – C – C

/

C

The problem with this kind of “broken arrow” is that it is the perfect configuration for getting stuck. Trans- fats tend to get stuck in the delicate membranes of the cells, part of the molecule going in, and part of the molecule sticking out. When this happens, the end of the fat molecule that isn't transported into the cell tends to be oxidized but not in a mitochondrial “furnace” of the cell. It simply burns a hole in the lining of the cell, leaving it vulnerable to damage.

But that's not the worst thing that happens with fat and cholesterol.

Fat, Saturated Fat, Trans- Fat, Cholesterol, and Calcification in the Arteries

The enemy of good cardiovascular health really isn't fat. Think about if for a moment. Fat is squishy. In the warm of the body, fat in the lining of arteries isn't substantial enough to impede the flow of blood (except in the most extreme cases).

Cholesterol is squishy, too. Many cold creams use pure cholesterol as a carrier. It would not be possible to slather them on your skin if cholesterol in its pure state didn't stay smooth and spreadable. But the cholesterol that causes clogged arteries is hard. When cholesterol hardens into plaque, the arteries lose their flexibility, and eventually a clot is almost bound to get stuck in the artery, where it can then cause a heart attack or a stroke.

Calcium Is the Culprit

How does that happen?

While the broken arrow of trans- fat make causes fatty substances to get stuck in the lining of the artery, it takes calcium to harden it into a dangerous plaque. When there is too much calcium in the bloodstream, it is available to harden into plaque.

So how do you get excess calcium out of your bloodstream? It's not like you should stop eating dairy products or taking calcium supplements. (Sorry, vegans, while the percentage of calcium in greens is in fact greater than the percentage of calcium in dairy products, greens are mostly water, far more so than dairy, and it's just not possible to get all your calcium or protein from veggies. You aren't a cow.) Ironically, however, people who take more than 1,500 mg of calcium supplements per day or who drink more than four glasses of milk per day are especially vulnerable to hardening of the arteries.