The Fats We Eat And The Things They Do to Our Bodies

What’s the first thing that comes to mind when you read or hear the word “fat?”

I’m a cook, so I picture a tub of lard. Tallow, maybe. Golden-yellow duck fat on special occasions. You know, in those white plastic buckets with the thin handles that sink into your skin and twist between your fingers.

If we asked a chemist, I bet you they’d picture something very different from you and me. To them, “fat” evokes an image of chalk-scribbled formulas on a whiteboard. Long chains of Cs, Hs, and Os — for carbon, hydrogen, and oxygen — both separated and linked together by straight lines.

Some lines are single, like em dashes. Others are double, akin to equals signs.

Those lines, as it turns out, and the things they tell us about the fat’s composition, can make all the difference in the world in terms of our wellbeing.

Take saturated fats. Coconut oil, duck fat, lard, palm oil, schmaltz, tallow are all examples of cooking fats with a high saturated fat content. They’re so solid at room temperature, you can scoop them up with a spoon and spread them over a slice of bread, like butter.

To a chemist, saturated fats look neat and orderly. Their formulas appear “right,” as if Mother Nature took a break from her usual mood of experimentation when creating them and sat down on the drawing board to create a formula for fats so proper, you’d think they were artificially created by a researcher in a lab:

In this formula, each C, H, and O represents a carbon, hydrogen, or oxygen atom (“atoms” being the single units of matter considered to be the building blocks of all material things).

We call these “fatty acids” because, in their simplest form, they are a chain of carbon atoms (Cs) with hydrogen atoms (Hs) attached to them, with a carboxyl group ( — COOH) at one end.

Notice the lines — apart from the double line between the C and the O in the carboxyl group, which indicates one end of a fat, all lines between two adjacent Cs are single.

That’s how to tell you’re looking at a formula for saturated fat. The Cs are connected to other Cs with single lines only.

Mother Nature was back in full-on experimentation mode when she conceived of unsaturated fats. “Hmm…” she mused, a look of wit and concentration on her face, “What if somewhere in the middle of the formula, we made the bond between two carbon atoms double?”

And so, unsaturated fats were born.

Unsaturated fats are fats that have at least one double carbon bond, meaning two Cs connected to each other with a double line. Unlike saturated fats, which have straight-line formulas, the formulas for unsaturated fats are windy, like that Snake game we used to play on our Nokias before the late Steve Jobs brought us the iPhone.

Unsaturated fats can be monounsaturated, with just one double carbon bond, or polyunsaturated, with two or more double carbon bonds. The more the double carbon bonds, the twistier the formula — some of these things are funkier than an 80s disco legend on the dance floor.

Almonds, avocados, cashews, hazelnuts, olives, pumpkin seeds, and sesame seeds are common sources of monounsaturated fats (and so are their oils). Chia seeds, corn, flax seeds, hemp seeds, herring, salmon, trout, tuna, and walnuts, on the other hand, are common sources of unsaturated fats (and, consequently, so are their oils).

If our eyes can see the difference from afar, imagine what our cells must be thinking when presented with the challenge of breaking these things down. Our cells, after all, are some busy creatures. They toil 24/7 to break apart the nutrients we feed them with and either use them as building blocks for creating other molecules or store them somewhere in our bodies for a rainy day.

As it turns out, our cells need more energy to break down unsaturated fats than they do to metabolize saturated fats.

It’s logical, when you come to think of it. Say your job is to solve puzzles all day (if you’re reading this and you’re hiring, DM me!). The simpler the puzzle, the easier it is to solve, and the less time that solving takes you. Saturated fats, with their single carbon bonds and their straight formulas, are that simple puzzle for our cells. Unsaturated fats are trickier. More complex. Those double carbon bonds and the twisty chains that they result in are more challenging.

But here’s the thing: like the neurons in our brains, the rest of the cells in our bodies love a challenge. They live for it.

Study after study shows that increased intake of saturated fats spikes the bad cholesterol levels in our blood — while increased intake of unsaturated fats, as part of a balanced diet and in moderation, tends to not only increase good cholesterol but also fight bad cholesterol.

If you want to live a long, healthy life, this is very, very important.

Remember how we said that saturated fats are solid at room temp? If you try to rinse lard or tallow down the kitchen sink, they’re going to clog up the pipes under your sink so bad, you’ll need to use solvents to undo the damage.

Bad cholesterol (or, in chemical terms, low-density lipoprotein)? It does the same thing to your body: It builds up on the walls of your blood vessels and forms plaque that can lead to heart disease or even stroke. Good cholesterol (high-density lipoprotein) is like that solvent. It absorbs cholesterol in the blood and carries it to your liver, the organ tasked with the job of flushing it from your body.

It’s not all black and white, though. Recent research suggests that the saturated fats that show up in our food contain important building blocks and energy depots for our bodies. Which means we probably shouldn’t be cutting back on them completely — but rather limiting our intake of them.

The best way to limit saturated fat intake, scientists point out, is not to swap them out with carbs from plant-based drinks and rice cakes, but to eat more foods that contain unsaturated fat. The less processed that source, the better. Our cells like a challenge! Yes, extra virgin olive oil is great. It’s one of the staple foods of the Mediterranean diet. But, in a way, olives may be even better because it takes your body more energy to digest them. And you get not just the fatty acids, but also all the other good stuff naturally present in them.

What’s interesting here is that, when it comes to polyunsaturated fats — the kind with the double carbon bonds, or two or more pairs of Cs linked by a double line — we have a hell of a lot more to figure out.

Take omega-3s and omega-6s.

Omega-3s have their first double carbon bond at the third carbon atom from the methyl end (that’s the opposite end of the carboxyl group end we went over earlier):

(This simplified way of writing out formulas omits the Cs and Hs, putting the focus on the location of the double carbon bonds and carboxyl group at one end instead.)

In the case of omega-6s, the first double carbon bond is at the sixth carbon atom from the methyl end, like so:

Both omega-3s and omega-6s, being polyunsaturated fats, are naturally found in food and generally good for you. But some speculate that too much omega-6s, already abundant in the Western diet because of the seed oils we cook with and the processed foods we eat (think snacks, fast food, frozen pizza, freezer meals) can cause inflammation. “Speculate” is the right word to use here. The body’s relationship with omega-6 is complex, experts warn, and more research is needed before we can confidently weed out causation from correlation and conclude what’s true.

What does that leave us with?

I can’t help but make the layman’s observation that omega-3s seem more complex, structurally, than omega-6s. My research suggests that of the fatty acids most commonly found in food, omega-3s tend to have 3 to 6 double bonds, while omega-6s have 2 to 4 double bonds. Once more, our cells, all other things being equal, seem to love a challenge.

Look, I’m no expert in nutrition:

I’m just your regular guy who happens to know how to cook, loves to write, and cares about his health as much as his appetite and reluctance to work out allow him to. But from reading all the research that led me to write this piece, I can give you the conclusions I’ve drawn for myself.

My two top takeaways are that, (a) fats are not necessarily bad, and (b) less processed food is always — without exception — better.

For me, this means that as much as I like duck-fat fries and lard tamales, I’m opting for extra virgin olive oil (the real kind) for most of my cooking, except for when I’m cooking with high heat.

Even though the research about omega-6s is inconclusive, I’m limiting my use of seed/vegetable oils to searing and deep-frying (where I need a neutrally flavored oil that won’t impart a strong taste on my food and that’s capable of withstanding high heat).

Lastly, I’m rethinking the way I buy, cook, and eat food. More brown rice and quinoa, less bread and pasta. More nuts, fewer nachos. Cheese for flavor but not substance. Avocados, olives, sustainably caught fish, meat from grass-fed animals — all said to be sources rich in omega-3s.

As a doctor once said to me, “Your health’s like your credit card. One splurge won’t do you much harm. Splurging every day will put you in debt.”

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