Saturated and Unsaturated fats


One hears a lot about the battle between saturated vs. unsaturated fats in nutrition. But what are they? And, chemically speaking, what is the difference between them?


Warning: Some scientist talk ahead – bear with me.


The ties that bind

To begin with, let's talk about how atoms get bound together. This can happen in many ways, but here the important mode is called covalent bonding. Here a pair of electrons is shared between two atoms.

This shared pair holds the atoms together. Expanding on this, there are different ways to describe this bond based on the number of electrons shared.


Hydrocarbons – the backbone of life

In the chemistry of life, carbon is the foundation of everything. Sometimes these carbons form a ring ...


… and sometimes a chain.


Octane (the main ingredient in gasoline) and Teflon come in chains, as shown above.


Carbon has a taste for four bonds (shared pairs of electrons) in total. So carbon can share electrons with four other atoms, with one pair each, or two atoms with two pairs each, etc.


The fat life

So what is fat – or fatty acid as the proper term has it? Simply this, fat is a carbon chain surrounded by hydrogen atoms except for one end with a particular group of atoms called a "carboxyl group."


Saturated and unsaturated fats

Now for the meat of the issue.


Saturated fat is a fat molecule where all the carbons in the chain are connected by single bonds (single pairs of shared electrons) to its neighbors in the chain or nearby hydrogen atoms.

In the above diagram, the dark spheres are carbon and red oxygen. Single lines are single bonds, and double lines double bonds.


Unsaturated fats are just that, fats that are not saturated. Or rather, they are fats where some of the carbons have a double bond (2 pairs of shared electrons) between them.


What difference can it make?

Okay, one might say, so a pair of carbons share two pairs of electrons vs. just one.


Big deal!


Well, it actually is a big deal.


The reason is that the double bond is a kind of loose cannon. The reason is that double bonds contain a second electron pair that can react with other molecules, corrupting the fat molecule. This makes unsaturated fat molecules much less stable and more corruptible. As a result, pure unsaturated fats tend to have shorter shelf lives.


In contrast, saturated fats like lard and coconut oil are chemically very stable with their single bonds. How stable? Ask Hans Feldmeier, who opened up a 64-year-old can of lard that was still good.


In hindsight, the stability of these kinds of fats should come as no surprise. The human body needs to be able to store energy, long term, in a warm body. A fat with a long “shelf life” is definitely desirable. A wise creator certainly provided for this need.


What conclusions can be drawn regarding the health benefits of consuming one type versus the other?


I will let the reader decide for themselves.


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