Eat “good” fats and avoid “bad” fats – this is a piece of advice so broad that it often creates more confusion than clarity. But what if there are aspects of fats that go far beyond the simple label of “good” or “bad”?
What makes a fat, good or bad?
This is where we move past the vague dietary chatter of good and bad, and enter into the precise world of science to understand what truly feeds our body.
Understanding the term ‘Essential Fatty Acids’
When we think of fat, we often think of a single substance—the oil in a bottle, the ghee on our paratha, the butter on our toast, or as a number on a nutrition label. But if we go a layer beyond the surface, the “fat” in our food is not a monolith. It’s a precisely constructed molecule built from smaller, more fundamental components.
The vast majority of what we call fat—over 95% of it—exists in a specific structure called a triglyceride. The name itself gives you the blueprint:
- “Tri-“: Meaning three.
- “-glyceride”: Referring to a backbone molecule called Glycerol.
So, a triglyceride is simply one glycerol molecule holding three fatty acid chains attached to it.
Now, while the glycerol backbone is the consistent anchor, it’s the fatty acids—the three chains—that give a fat its specific identity and health properties.
Think of it like three different tools attached to the same power drill. The drill (glycerol) provides the base power, but it’s the specific attachments (the fatty acids)—a drill bit, a screwdriver, a polishing head—that determine the actual function.
What are fatty acids?
A fatty acid is a chain of carbon atoms decorated with hydrogen atoms, featuring a reactive acid group at one end (which gives it the “acid” part of its name). The length of this carbon chain and the nature of the chemical bonds connecting them can vary dramatically. This variety creates a vast alphabet of different fatty acids, each with a unique shape and function.
This structural diversity allows them to perform incredibly specific jobs in the body:
- Dense Fuel: They can be broken down to provide a highly efficient source of energy.
- Structural Integrity: They are the primary architectural components of every cell membrane, governing its fluidity, flexibility, and what passes in and out.
- Cellular Signaling: They serve as precursors to an entire class of powerful, hormone-like signaling molecules (called eicosanoids) that regulate critical processes like inflammation, immunity, and blood clotting.
Whether a fat is classified as saturated or unsaturated, whether it behaves as inflammatory or anti-inflammatory, and most importantly, whether it is essential or non-essential—all of this is determined by which specific fatty acids are part of that structure.
It’s worth noting that our body is an incredibly sophisticated chemical plant. Given the right raw materials like carbohydrates and proteins, it can skillfully manufacture many of the fatty acid chains it requires for general energy and structure—specifically, most saturated and monounsaturated fats. It has this part of the job covered.
Right raw materials: like yarn goes into making sweater
However, that manufacturing capability has a critical limit. There is a special class of fatty acids, with a unique chemical structure, that our internal factory a.k.a. our body cannot build from scratch- we must get them from our diet.
Such fatty acids are called the essential fatty acids. In nutrition, the term essential is not a suggestion—it’s a strict classification. An ‘essential’ nutrient is one that is absolutely required for your body to function, but which it cannot synthesize on its own. You must obtain it from an external source, i.e., your diet. It is a biological mandate.
Luckily for the human race, the list of essential fatty acids is not long. For all the complexity of human biology, the entire system hinges on two—and only two—fundamental families, which act as opposing forces in a delicate balance.
The two essential families: A tale of opposing forces
To understand the profound importance of the two essential fatty acid families, let’s step away from nutrition for a moment and consider a real-world crisis: you get a sharp cut on your finger.
Instantly, your body is faced with multiple, simultaneous threats. You’re losing blood. The protective barrier of your skin has been breached, leaving you vulnerable to invading bacteria and viruses.
In this moment, your body deploys a highly coordinated, two-phased emergency protocol.
First phase is the emergency response:
- Sound the alarm: Release chemical signals inform other parts of the body about the breach
- Quarantine the area: Trigger acute inflammation—the familiar redness, swelling, and heat—to form a physical barrier, preventing pathogens from spreading.
- Stop the bleeding: Signal for blood to clot and blood vessels to constrict.
- Call in the troops: Attract white blood cells to the site to attack any invaders.
The first phase prioritizes immediate survival over long-term comfort – saving the house on fire but also causing some damage.
Once the immediate threat is neutralised, the second phase of resolution and repair begins:
- Sound the all-clear: Release a different set of chemical signals that the breach is handled.
- Dismantle the barricades: Actively reduce the inflammation, calming the affected area.
- Clean up the site: Clear away the debris of the dead cells and leftover biochemicals.
- Begin reconstruction: Lay the groundwork for new, healthy tissue to be built, restoring the finger to its original state.
For you to heal perfectly, your body needs to be brilliant at both phases. A weak emergency response could lead to a life-threatening infection. But an inability to call off the alarm and begin reconstruction leads to a different problem: chronic inflammation, a state where the body remains stuck in a low-grade, destructive emergency mode. This is a system defined by balance, a dynamic push-and-pull between crisis and resolution.
This is precisely where the two essential fatty acid families come in. They are the raw materials your body uses to build the molecules that command these opposing forces/phases.
The essential Omega-6: Fuel for the emergency response
Omega-6 is a family of essential polyunsaturated fatty acids that our body needs for survival but cannot create on its own. While the term ‘Omega-6’ refers to a whole family of fats, the one we primarily consume through our diet is the parent molecule, Linoleic Acid (LA).
So, how do we consume it? The fats we eat are mostly in the form of triglycerides—a glycerol molecule attached to three fatty acid chains. In many common vegetable oils, a high percentage of these fatty acid chains are Linoleic Acid.
When you use oils like sunflower, safflower, or soybean oil, you are feeding your body a significant amount of Omega-6.
Once consumed, this Linoleic Acid is converted by the body into the more biologically active Arachidonic Acid (AA). This AA is then stored in our cell membranes, ready to be used as the key to many of Omega-6’s functions.
The functional role
As we discussed, this is the body’s emergency response team. Its primary job is to act as an ‘On Switch’ to deal with immediate threats. When a cell is triggered by injury or infection, the stored AA is released and converted into powerful signals called eicosanoids, which act like local hormones to:
- Initiate acute inflammation: The necessary, helpful swelling and redness that quarantines an injury and calls immune cells to the site.
- Promote blood clotting: Signals platelets to become sticky and seal a wound.
- Activate the immune response: Acts as a broadcaster to alert and mobilize your immune system against pathogens.
Good food sources of Omega-6 (Linoleic Acid) are abundant and include walnuts, sunflower seeds, poultry, and soybean oil, to name a few. When you eat these foods, your body frees the Linoleic Acid from the fat, absorbs it, and gets it ready for its vital role as the body’s first responder.
The essential Omega-3: The Resolution & Repair crew
Just as Omega-6 acts as the body’s essential “on switch,” the Omega-3 family of polyunsaturated fatty acids acts as its indispensable counterpart: the “off switch,” or the resolution and repair crew. It is the second of the two essential fat families that our body cannot produce on its own and must obtain from our diet.
The Omega-3 family
Thinking of Omega-3 as a family is even more crucial than for Omega-6, because unlike Omega-6, the different members of Omega-3 have very distinct roles and sources.
The parent molecule of this family is Alpha-Linolenic Acid (ALA). This is the essential Omega-3 found in plant-based foods. When we feed ALA to our body through various omega-3 rich plant-based foods, our body uses a similar LA to AA transformation to convert ALA into Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA).
Plant based Omega-3 sources
These are the most biologically active forms and are directly responsible for most of the health benefits we associate with Omega-3s.
However, only about 5 percent of ALA converts into EPA and DHA due to our body’s natural inefficiency. It therefore becomes crucial for us to consume omega-3 in potent EPA and DHA forms.
The functional role
If Omega-6 sounds the alarm, Omega-3 is the crew that cleans up, rebuilds, and restores peace. Its primary job is to resolve inflammation and promote healing. It does this by creating its own set of powerful signaling molecules (including a different class of eicosanoids, as well as resolvins and protectins) that:
- Actively resolve inflammation: They don’t just block the “on” signal from Omega-6; they generate a powerful “stand down” and “clean up” signal that actively dismantles the inflammatory process once it’s no longer needed.
- Support cardiovascular health: They help make blood platelets less sticky, improve the flexibility of blood vessels, and support healthy triglyceride levels.
- Provide structural integrity: This is a key role for DHA. It is a primary structural component of our cell membranes, especially in the brain’s grey matter and the retina of the eye. Its presence keeps membranes fluid and flexible, which is vital for cellular communication.
Dietary sources: A two tiered approach
Because the conversion from ALA is so inefficient, we have to think about Omega-3 sources in two distinct categories:
- Major sources of ALA (The Parent Fat): These are important but remember that only a fraction will be converted.
- Flaxseeds (Alsi) and flaxseed oil
- Chia seeds (Sabja)
- Walnuts (Akhrot)
- Soybeans
- Direct sources of EPA & DHA (The Active Fats): This is the most effective way to get these critical nutrients.
- Fatty Fish: Salmon, Mackerel (Bangda), Sardines, Herring, and Hilsa (Ilish).
- Fish Oil Supplements: A concentrated source of EPA and DHA.
- Algae Oil: The best plant-based source of direct EPA and DHA, as algae is where fish get their Omega-3s from in the first place. This is an excellent option for vegetarians and vegans.
The challenge of our modern diet is that it’s often flooded with Omega-6 fats from processed foods and certain vegetable oils, while being deficient in Omega-3s. This can leave the body’s alarm system stuck in the “on” position, without enough of the calming, repairing influence of Omega-3s to restore order.
Your goal, therefore, isn’t to fear or eliminate Omega-6, but to create harmony. By making conscious choices—moderating processed foods while actively incorporating sources of Omega-3 like flaxseeds, walnuts, and fatty fish or algae oil—you shift the balance back in your body’s favour.
Congratulations for making it this far. You are officially no longer a beginner. You are now equipped with the fundamental knowledge to understand how fats truly work, empowering you to make choices that nourish your health from the most essential level.