Seed Oil vs. Tallow Debate: What’s Really Best for Your Health?

Are toxic seed oils destroying your health? Or are they just the latest nutritional scapegoat? And what's with all these people demanding that fast food chains bring back the tallow fries? Can't you just make french fries with potatoes, tallow? Is this a serious health movement? Or is it just nostalgia with a sprinkling of conspiracy? We're going to untangle one of the most heated and fascinating debates in the nutrition space right now, the seed oil controversy. Or at least, we're gonna start. Because before we dive in, I want to be upfront. This video will break down key points you need to know about the seed oil controversy in plain English, but if you want a deeper dive, if you want the nuanced details, the full human trial data, molecular breakdowns, and all the charts, I've got a written breakdown linked below that can be found at staycuriousmetabolism.com. For those who are real nuance nerds, that's where I want you to go after you watch this video. And credit to some other scientists, colleagues, physicians, friends for their input on this letter. Also, it may end up being a living document, updated based on inputs from our community, either on the newsletter or here in the comments. I want to keep this updated and an open conversation. Okay, with that, let's set the stage. The seed oil debate has become a keystone issue for the Make America Healthy Again movement. For example, Robert F. Kennedy Jr. has called seed oils on national television, "Seed oils are one of the most unhealthy ingredients that we have in foods." And that, and similar comments in the movement, has sparked a whole counterculture movement to replace industrialized plant-sourced fats, also known broadly as seed oils with animal fats like butter and tallow. In fact, there are public calls to bring back the tallow fries to fast food chains like McDonald's. It's basically the dietary version of "Make fries great again." And honestly, the market is responding. Restaurant chains are responding. Some have literally started R— bleeping the fries, meaning swapping seed oils for beef tallow for presumed health benefits. But let me be clear, this video isn't really about French fries. It's about how we dissect conflicting data in nutrition and why there's so much confusion around animal versus plant fats, especially when it comes to seed oils. Because the real problem is this: different sources of evidence tell different stories, and each side thinks their argument is airtight, Rather than trying to resolve the inconsistencies in the data, we shout past each other, we dismiss and bicker. But today, in this video and in the associated letter, I want to slice through the noise. No oxidized thinking allowed. We're gonna talk through the physiological rationale behind the seed oil controversy. Then we're gonna zoom out to talk about some of the human data, including studies showing health risks and also ones showing potential health benefits of seed oils. We'll look at the contradictions, where they come from, and how we can start moving towards resolving them. Finally, I'll share how I personally approach cooking fats, seed oils, and food choices in general. Alright, with that long preamble over, let's get into it. Let's start with the bold claim you might have seen on social media. Some influencers and science communicators are arguing that foods cooked in that seed oils, including French fries, are as bad for your health as smoking cigarettes. Jeez, bold claim, right? Well, what's this argument based on? It starts with the chemistry of plant fats and seed oils. Many seed oils, basically all of them, are rich in omega-6 polyunsaturated fatty acids, or PUFAs for short, with linoleic acid being the most common omega-6 PUFA. But here's the issue: PUFAs like linoleic acid, they're chemically fragile. They are. So when exposed to high heat, like in a deep fryer, they're highly prone to a process called oxidation. Oxidation can transform these fragile fats into harmful substances called lipid oxidation products. Things like aldehydes, some of which are known to damage cells, damage DNA, and promote cancer, carcinogenesis. In contrast, saturated fats, like those found in tallow and butter, are much more stable under heat. This isn't theoretical. If you compare, say, sunflower oil, one of the so-called "hateful 8" seed oils, to butter or tallow in a lab setting at typical frying temperatures, about 180°C, you see way more harmful aldehyde formation from the seed oil. And here's where the cigarette comparison comes from. According to the WHO, World Health Organization, the maximum safe daily intake for one harmful aldehyde, acrolein, is around 525 micrograms per day. But a single standard serving of potato chips or French fries can contain 1,000 to 1,500 micrograms. That's roughly the equivalent of the aldehyde exposure from smoking 25 cigarettes per day. Now, to be clear, crystal clear, I'm not saying eating fries is literally the same as smoking 25 cigarettes per day. I think that's an oversimplification, but that is one origin of the claim. And honestly, it's not entirely unconvincing. What do you think? So based on that physiologic rationale, the pushback to bring back the tallow fries, it kind of makes sense, doesn't it? Better taste, fewer carcinogens, win-win! Well, maybe. But let's buckle in, because the story gets much more complicated. Let's start by extending the logic. If seed oils as a broad class, plant fats, and omega-6 are fragile, prone to oxidation, and are going to generate harmful byproducts, they must be bad for your health, right? The elites have misled us. Animal fats like tallow are the real health food, and omega-6 fats should be avoided at all costs. Sounds simple, but as you can probably tell, I'm being intentionally hyperbolic, although I bet somebody's gonna take that out of context and make it a clip. But anyway, that aside, this is not black and white. This black and white thinking is exactly where people fall into traps and get trapped in echo chambers. Here's why the story isn't so simple. Many human studies, not just in test tubes, but real-world human data show that, believe it or not, higher levels of linoleic acid, the same omega-6 found in seed oils, are associated with better health outcomes. That includes linoleic acid circulating in the body and in tissues like fat tissue. For example, a meta-analysis of 30 studies found that people with higher linoleic acid levels in their blood or fat tissue had lower risk of heart disease. This included a reported 34 to 40% reduced risk of dying from cardiovascular disease. And another meta-analysis of randomized controlled trials showed that swapping saturated fat for PUFA, like that in seed oils, reduced the risk of coronary heart disease by 10% for every 5% increase in PUFA intake. Weird. So according to these data, your arteries might actually like walnuts. And yes, even some seed oils, a lot more than Twitter does. So the human data trumps the test tubes, right? And the animal data? Well, not quite. Confused yet? Good. That means you're paying attention. We've got seemingly contradictory lines of evidence. On the one hand, omega-6 fats, like linoleic acid, are chemically fragile, prone to oxidation, can form toxic byproducts that may promote disease. But, On the other hand, a decent body of human research shows that higher omega-6 levels in the body are associated with better heart health. So who's right here? What's the real answer, the biological truth? Well, who's right? Both. And neither. Here's how we start to resolve the confusion. First, context matters. A lot. One of the most overlooked factors is that many studies showing benefits from omega-6 fats also include increases in omega-3 fats, like those found in fatty fish, which are established as anti-inflammatory and heart-healthy. In fact, in one ingenious meta-analysis, they separated studies based on whether the intervention increased both omega-3 and omega-6 fats, or just omega-6 alone. Now, what were the results when you partitioned the studies in this way? When both omega-3 and omega-6 intake was increased, there was a significant 22% reduction in heart attack and heart disease deaths as a combined outcome. But in trials that increased only omega-6, there was the opposite trend, actually a trend towards increased cardiovascular risk. Isn't that interesting? The takeaway: it's not just about one isolated nutrient, say omega-6 or linoleic acid. It's about the bigger dietary pattern that really matters. So let's keep going. Another critical factor is the difference between whole food sources of fats and highly processed industrialized oils, and often these get lumped together in studies. Let's just take an example: sesame seeds and cold-pressed sesame oil. Technically, they're really rich in omega-6 and linoleic acid, but they also contain certain natural antioxidants that help protect those fats from oxidation and forming those lipid oxidation products, even under heat. In that sense, and this is going to sound weird, but sesame oil behaves more like tallow or butter than your typical processed seed oil when it comes to heat and stability. The same holds true for nuts, seeds, and other whole plant foods rich in omega-6 fats. The walnut is not the same as the deep fryer oil at McDonald's. And it's often not the fat itself that's the problem, just to double down on this, it's how we process, refine, and cook it. And then, to complicate matters further, there's you—your individual biology. It's often said that you are what you eat, but that is not true. A better version is you are what your body does with what you eat. Your genetics, your metabolic health, your hormones—they all influence how your body processes omega-6 fats like linoleic acid, which changes circulating and tissue levels. In effect, this means there are conditions where lower linoleic acid, lower omega-6 levels in the body, they can actually result from states of ill health because they're being processed differently. This can potentially lead to an association whereby lower levels of omega-6 in the body associate with poor health outcomes, but it's not because sick people are eating less omega-6 per se, but because it's processed differently in the body. Now, I'm not claiming that alone explains the discrepancy in the data, I'm just trying to highlight— this is not simple. Now, all of that said, I'm not here to bash Tallow either. If you follow me, you know I've defended, for lack of a better term, saturated fat as well. See these two videos if you want examples. I can walk the walk, not just talk the talk, although I guess I'm talking in the videos. But anyway, bottom line, it's complicated. Oversimplification The headlines like "seed oils are toxic or healthy" or "animal fats are toxic or healthy," they ignore the reality that nutrition and metabolism is full of nuance. So now, just getting into the practical, here's how I approach this seed oil topic in my actual life. First, I don't fear whole food sources of omega-6. Nuts, seeds, they're staying in my diet. Second, for high heat cooking, I stick to stable fats. This means yes, tallow and ghee and butter and coconut oil, also avocado oil and macadamia nut oil. These are lower in fragile PUFA if I'm heating the fat. Third, I care more about my overall metabolic health and my markers, my biomarkers, than demonizing one nutrient. That means I measure my markers and I update my approaches based on my personal data, not based on the biggest megaphone on social media and what it tells me. And finally, finally, French fries They're french fries. Whether cooked in seed oils or tallow, they're not a health food. But hey, if RFK Jr. wants to fund a $10 million randomized control trial comparing tallow fries to seed oil fries, I would happily offer to acquire the IRB, recruit and run the study, and for science exclusively, I'll even taste test them. So, to wrap up, seed oils aren't poison, and tallow isn't salvation. In the French fry wars, Honestly, they just reveal how nutrition science gets flattened into black and white soundbites. Truthfully, biology does not care about caps locks or hashtags. So if you take one thing away from this video, it's context matters, metabolic health matters, food processing matters, and science communication, it needs more nuance. Anyway, thanks for watching, and again, if you want the full deep dive with the detailed study breakdowns, the graphs, all the technical details, and what I suggest concretely for moving the field forward from both the scientific angle and the social media communication angle, please see the newsletter link below. And if you're gonna eat french fries, just skip the ideological wars and enjoy the fries. Stay curious. Peace.