New research is showing that it’s not fat itself that can be dangerous for your health — its the type of fat. Here, Miranda, one of our resident nutritional scientists, breaks down what we now know about healthy fats and how to get them in your diet!
Last Updated: June 19, 2019
Does the phrase “healthy fats“ sound like an oxymoron to you? It does? Well, then, hi-there my fellow 1990s kid!
You and I grew up in full-blown fat-phobic world.
Do you remember the unbridled obsession with lean, white meat?
The country-wide switch to 2% milk?
The sudden appearance of low-fat cheese?
And fat-free junk food: cookies, cakes, chips?
Oh, and don’t forget the fat-free ice cream! Just writing about it brings back the minty, sweet, gooey weirdness of fat-free chocolate mint ice cream! Mmm, tastes like childhood!
If you’ve been following health and nutrition news for the last couple of decades, though, you cannot help but have noticed a serious change in the wind.
Fat has undergone a complete health makeover.
Now you see stories about butter (pure fat!) being healthy. And the phrase healthy fats is used — non-sarcastically — all over the place!
But are healthy fats a real thing? If so, how do they differ from unhealthy fats? And how do they help make you healthy?
I’m so glad you asked!
Are Healthy Fats a Real Thing?
The short answer here: yes!
While certain fats are associated with increased health risks — like high cholesterol, heart attack, stroke, and sudden cardiac death — other fats have the exact opposite effects. They protect against cardiovascular disease! Actually, they protect against a whole bushel of diseases!
So, what’s the difference between healthy and unhealthy fats?
Their chemical structure.
Healthy Fats vs. Unhealthy Fats
Both healthy fats and unhealthy fats are made up of molecules called fatty acids. Fatty acids are long chains of carbons and hydrogens with an organic acid on one end. In general, they look something like this:
In healthy fats, the fatty acids have a unique twist on this structure. They have at least one so-called cis-double bond.
If you remember from your high-school chemistry class, a carbon-carbon double bond forms when two carbons each ditch a hydrogen atom. Then, they form a bond to each other instead (Figure 2).
Since each carbon has two hydrogens to choose from, there are two ways a double bond can form. The healthy way is when both carbons ditch a hydrogen atom from the same side of their bond. That creates a cis-bond that looks like this:
Cis-bonds put a kink in the fatty acid (Figure 3). This makes it easier for your body to use them for making cell membranes and producing hormones.
Unhealthy fats, on the other hand, are really straight — with no kinks. There are two types of fatty acids that have this straight structure.
The first is the type of fatty acids without any double bonds. These fats are called saturated fatty acids. (Figure 1 shows a saturated fatty acid, palmitic acid.)
The second is a type of fatty acids called trans-fatty acids. Trans-fatty acids are the unhealthy way a double bond can form — with the carbons losing hydrogens from different sides of their bond (Figure 4):
This keeps a kink from forming, making a “straight” double bond (Figure 5). It behaves like a saturated fatty acid in your body.
Healthy, Healthier, Healthiest
Now, while all fats with a cis-double bond are healthy, some are healthier than others depending on how many cis-double bonds they have and where they are in their carbon chain.
Monounsaturated cis-fatty acids — or fatty acids with a single cis-double bond — are healthy.
Polyunsaturated cis-fatty acids — fatty acids with two or more cis-double bonds — are healthier.
And omega-3 polyunsaturated cis-fatty acids — fatty acids with more than two cis-double bonds and their first double bond between the 3rd and 4th carbon (Figure 6) — are the healthiest.
Why does having that first double bond on the 3rd carbon make these fatty acids so healthy?
To answer that, we need to get even more biochemistry-y for a second and talk about how your body uses polyunsaturated fatty acids and the importance of the omega 6:3 ratio.
Polyunsaturated Fatty Acids and the Omega 6:3 Ratio
One of the main things your body does with polyunsaturated fatty acids is to turn them into hormones that regulate your immune system. To do this, your body uses a series of enzymes. These enzymes turn fatty acids from your diet into the important hormones called prostaglandins and leukotrienes.
Now, what’s interesting is these enzymes use whatever polyunsaturated fatty acid you give them. They can’t tell if the double bonds start at the 3rd carbon or somewhere else (say, the 6th carbon).
They just go along, turning them into prostaglandins and leukotrienes. And they can’t move the double bonds from the original fatty acid to anywhere else in the carbon chain.
So, if you start with an omega 3 fatty acid, you get a leukotriene or prostaglandin with double bonds starting on carbon three. And if you start with an omega 6 fatty acid (where the first double bond is between carbon six and seven), you have a leukotriene or prostaglandin with double bonds starting on carbon six.
Alright, so why does it matter if your leukotrienes and prostaglandins have a double bond at carbon three or six? Because leukotrienes and prostaglandins that have their first double bond on carbon six are way, way more powerful immune stimulators.
That means that if you have too many omega-6-made leukotrienes and prostaglandins, your immune system becomes over-stimulated. It produces too many inflammatory chemicals and your body develops unhealthy chronic inflammation.
The Healthy Omega 6:3 Ratio
So, how many omega 6’s and omega 3’s in your diet let your body make the healthiest ratios of leukotrienes and prostaglandins?
Based on the current research, scientists think your body is healthiest if you consume no more than two omega 6 fatty acids for every omega 3 fatty acid you eat.
This makes sure you make enough omega-3-made leukotrienes and prostaglandins to keep chronic inflammation at bay!
Health Benefits of a Healthy Omega 6:3 Ratio
What happens to your body if you eat lots of healthy polyunsaturated fatty acids in an omega 6:3 of less than 2:1?
Well, naturally, you reduce systemic inflammation.
And what does that do to your body? A whole bunch of positive things!
Let’s check out 4 of the most important!
Healthier Blood and Blood Vessels
One of the roles immune-stimulating leukotrienes and prostaglandins have on your body is to slow down your blood flow and make your blood ready to clot.
When your immune system is in full-gear, it means you have an infection.
A good chunk of the time, it is an injury that let the infecting germ get in your body. So, your blood vessels are pre-programmed to get smaller and slow down blood flow (to help keep you from bleeding to death)!
And your blood is pre-programmed to respond to an active immune system with ready-to-clot blood to close off a wound!
Of course, this is great news if you are actually wounded. But if you’re not, these responses are dangerous.
Narrow blood vessels can keep blood from flowing the way you need to keep your cells healthy. And if you combine this with clot-happy blood, you’ve got a real mess!
Ready-to-clot blood is, of course, more likely to actually form a clot. And clots, in turn, are more likely to get stuck in narrow blood vessels.
Combined, this puts you at huge risk for a heart attack or stroke.
Read Next: How Aging Affects Your Cardiovascular System
By making sure your diet has a healthy omega 6:3 ratio, you can nip this entire process in the bud. You protect your blood, blood vessels, and cardiovascular health!
Inflammation in your brain keeps your nerves from working the way they are supposed to! In fact, inflammation is thought to be one of the key contributors to the development of depression, anxiety, attention deficit hyperactivity disorder (ADHD), and dementia.
Yet another effect of too many pro-inflammatory chemicals from an over-activated immune system is insulin resistance.
Certain inflammatory chemicals mess with your cells’ ability to respond to insulin. They keep signals from your insulin receptors from actually getting into your cells.
So, even though you have insulin telling your cells, “Open up! There is sugar out here!”, they don’t. This lets sugar build up in your blood and puts you squarely on the path to developing type 2 diabetes.
Reducing inflammatory chemicals in your body by eating a healthy ratio of omega 6:3 fats in your diet can help you take an early exit from the diabetes highway!
Healthier Immune System
This final health benefit might not surprise you much! An immune system that is not over-stimulated is a healthier immune system!
But the effects are really important. An unbalanced immune system is not only bad for your blood, brain, and metabolism — it’s bad for your immune system, itself!
If your immune system stays over-stimulated for a long period of time, it’s more likely that it will tip over into a full-blown autoimmune disorder.
Related Reading: Good Gut Health: The Secret to Preventing Autoimmune Diseases
Autoimmune disorders occur when your immune system starts recognizing and attacking your body’s own healthy cells as if they were dangerous (Check out this article to learn more about how this happens — and why your gut health likely plays an important role.)
By keeping your immune system calm with plenty of healthy omega 3s, you can help ensure it doesn’t spiral out of control into an autoimmune disease!
What Does a Healthy Fat Diet Look Like?
First off, a diet with a healthy balance of fats will have very low amounts of straight-chained saturated and trans fats. Luckily, saturated and trans fats are pretty well concentrated in just a couple of food groups:
- processed junk foods
Limiting your intake of these three types of food instantly skyrockets the percentage of fat in your diet that is made up of healthy, unsaturated fatty acids.
And how do you get a healthy omega 6:3 ratio?
Typically, those eating a standard American diet are getting far, far too many omega 6 fatty acids and not enough omega 3s. (Remember I said a ratio of 2:1 is good? Most Americans get more like 16:1).
To drive that number back down to healthy levels, you need to do two things:
- Fill up your plate with foods rich in omega 3s.
- Cut (or reduce) foods rich in omega 6s.
Which foods fall into those categories?
Foods rich in omega 3s include:
- fatty fish (salmon, anchovies)
- flaxseed and flaxseed oil
- leafy green vegetables (spinach, arugula, collard greens)
- Brussel sprouts
(Check out my list of healthy (vegan!) omega 3 fatty acid sources for more inspiration for ways to get these healthy fats in your diet!)
Foods rich in omega 6s include:
Aim every day to consume plenty of omega 3-rich foods and keep an eye on your portions of omega 6-rich foods. You’ll see your ratios hit healthy levels in no time!
Take Home Message
We’ve come a long way from the fat-phobia of the 1990s!
Now we know that not only not all fat is unhealthy for you, but that some of it is actually very healthy.
Polyunsaturated cis-fatty acids help protect your body from disease, especially if they are found in your diet in the super healthy omega 6:3 ratio of 2:1 (or less!).
Such healthy fat intakes can protect your blood, blood vessels, brain, immune system, and metabolism.