PUFA: The Preponderance of the Evidence

Why I'm not 100% sure PUFA did obesity, but I'll probably never eat seed oils again

Typical PUFA shill at work

If you’ve read this blog for a while, or interacted with me on Twitter, on Reddit, at work, or at the grocery story, I’ve probably talked your ear off about seed oils.

I suspect seeds oil are behind the modern epidemic of “diseases of civilization”: obesity, diabetes, heart disease, stroke, Alzheimer’s, maybe cancer. Probably more.

What I call Modern Pufa Theory (MPT) seems to fit the 8 Mysteries of Obesity as laid out by Slime Mold Time Mold better than anything else I know of.

We have an epidemiological match, a match for the historical trend, we have various mechanisms, we have studies in both mice and humans, and, anecdotally people on the internet doing crazy internet diets seem to do really well if they’ve cut out seed oils for at least a few months.

Why I’m not 100% sure PUFAs cause obesity..

Time frame of experiments

Any good hypothesis needs to be falsifiable. Pro-seed oil people sometimes accuse MPT of being unfalsifiable, but that’s not true - it’s just very difficult to falsify. But then we pretty much have to expect any correct theory of obesity/diabetes to be somewhat complicated or difficult to try, or we would’ve figured it out ages ago.

What makes MPT both attractive (in terms of what it can explain that other theories can’t) and difficult to falsify is the fact that PUFAs you consume will be stored as body fat. If you subsequently stop eating seed oils entirely, those stored PUFAs will still constantly enter your blood stream from your adipose tissue. It might take years to fully resaturate your body fat, with estimates ranging anywhere from 4-7 years, depending on how much PUFA you had stored to begin with.

For reference, in weight-stable people, the half-life of adipose tissue PUFAs was just under 2 years, meaning if you want to lower your adipose PUFA from 16% to the “ancestrally correct” 2%, you’d need to strictly avoid PUFAs for… 6 years.

Obviously it’s difficult to run a randomized controlled trial on a group of people for 6+ years. So while MPF might not be unfalsifiable, it’s definitely tricky to validate.

That said, several people in r/saturatedfat who’ve been avoiding PUFA like heck for years now report that, basically, “any diet works now” and foods that previously made them obese and diabetic are now totally fine. I suppose I’ll let you know in 6 years ;)

Been wrong before

Another big one is that I was previously 100% convinced that “carbs did it” and keto was the solution. I was so convinced of this that my faith lasted about 4-5 years into having gained back 100lbs while still on keto. Talk about zeal!

I did have the added benefit that ketosis has therapeutic effects for me, putting my Non-24 into total remission.

Maybe that was a trap in terms of obesity: keto delivered such outstanding therapeutic results that I was willing to ignore the reality of constant weight gain on “dirty keto.”

In any case, it’s hard to be 100% convinced PUFAs did it when you’ve been wrong before. I don’t know if it’s 95% or 98% or what, but I’m only “pretty convinced” instead of totally, 100%, positively convinced.

..but I'll probably never eat seed oils again

In the just over 1 year I’ve been cutting out seed oils seriously, I’ve experienced a bonanza of great health benefits:

• Lost 66lbs

• Down from a 46 jeans to a size 36

• Down from 3XL to L/XL shirts (depending on brand)

• Way reduced gum bleeding at dentist

• My vision is back to what it was in my 20s

• Dramatically reduced sunburn (45min used to burn me to a crisp, now 2h in straight summer noon sun barely turns me pink)

• Digestion went from what I perceived as good to “perfect”

• No more stomach acid reflux

• Haven’t really had a headache in… can’t remember?

• General well-being dramatically improved

• Often times spontaneously full of physical/mental energy, requiring me to go outside for a walk or write a long rant on this blog or reddit

You know what makes a man pretty convinced seed oils are the devil? All of the above.

What’s the upside of seed oils, anyway?

As far as I can tell, there’s no upside to eating any seed oils, ever, and no downside to cutting them out.

Even most “healthy, whole food, cArOliEs” people don’t actually advocate for eating seed oils, and they’ll point out that the government food pyramid/plate/recs/whatever they call it now don’t suggest you chug seed oils, just to avoid saturated fat.

Pretty much the only change attributable to seed oils seems to be that they lower your LDL when compared to similar saturated fat intake. But after over a decade of high-fat paleo + keto I’ve been exposed to so much data and so many anecdotes saying the opposite, I don’t believe lowering LDL is in any way beneficial.

Just for safety, I’ve taken a CAC (coronary artery calcium) scan and got the perfect score - 0 calcification - several times now. I suppose I’ll repeat that every few years, just in case.

Fact is, we don’t see ketards and carnivores dropping left and right of heart disease. If saturated fat and high LDL were really as bad as suggested by the LDL haters, we should see a drastic effect. We don’t. There’s literally 1 guy (The Carnivore Kid) that everyone points to, and he had a heart attack only a few months into carnivore, which he himself attributes to his prior Standard American Diet.

In addition, lower LDL is actually correlated (which is the best we have) with HIGHER all-cause mortality. Now this might just be because being sick is terrible for your LDL, but hey, that’s kind of the crux with epidemiology, is it? Works both ways.

In conclusion, I don’t see a single reason to eat any seed oils whatsoever. I didn’t consciously eat seed oils in the 7+ years of keto, I just didn’t realize how much I was getting from commercial salads, prepared “dirty keto” foods, and fatty chicken/pork like bacon.

This is not a criminal court, and I don’t need to be certain beyond a reasonable doubt

The next reason is: I don’t need to be certain beyond a reasonable doubt. I’m not deciding to send a potentially innocent man to the chair.

Since there’s basically no downside to dropping PUFAs except possibly maybe slightly increasing CVD risk (see LDL above), and a slight inconvenience to myself, I just don’t think it’s a big deal.

Even civil court cases don’t use “beyond a reasonable doubt” but “preponderance of the evidence.”

So if the PUFA-deniers argue that I can’t prove with human RCTs how seed oils caused everything, my reply is: I can’t and I don’t have to. I’m just making an informed decision in an environment of uncertainty, and the risk/benefit analysis of cutting out seed oils aggressively seems pretty obvious to me.

There is currently no hypothesis that can be proven “beyond a reasonable doubt” with acceptable RCTs, but in the absence of certainty, I still have to eat. We can’t all fast until The Science figures this out.

No Null Hypothesis

Another thing that tends to annoy me when discussing nutrition with more “mainstream” people who demand more serious proof: we don’t have a null-hypothesis, or at least we can’t agree on one.

We know people weren’t all obese and diabetic and dying from heart attacks in the 1960s, and it was even better in the 1920s, and basically it was better the earlier we go.

We just don’t know what’s different now. What got worse?

With a diabetes rate of 12%, an obesity rate of 43%, and an overweight (incl. obesity) rate of 74% in this country, I’d say that the ship is on fire and what we’re doing is OBVIOUSLY not working.

So you can demand serious proof and that’s cool and stuff, but if there is one thing we don’t need any more proof for - what we’re doing isn’t working.

The idea that “PUFAs are innocent until proven guilty” doesn’t apply. Something’s clearly catastrophic in our food environment. There’s a dead body on the floor, and a smoking gun next to it. We know something in the environment is extremely messed up, and nobody gets to leave the building until we know who did it.

You can demand certainty beyond a reasonable doubt after the fact in a criminal court. You can’t apply this standard while you’re still locked in the mansion with the killer on the loose.

I think Kenneth Branagh makes a fantastic Poirot, despite his.. “interesting”.. accent

The Preponderance of the Evidence

So what is this preponderance of the evidence? I’ll admit that I, like the seed oil-doubters, believe each of these is imperfect, and we can’t fully prove PUFA did it yet. But we do have a whole bunch of evidence to preponder.

• Epidemiology: There are hunter-gatherers that eat mostly fat (Inuit), protein (Masaii), and starch (Tukisenta). One thing the healthy ones all have in common: they don’t eat industrial seed oils. How could they, they don’t have hexane.

• Historical trend: Looking back, PUFA consumption was practically zero prior to 1900, and has risen steadily ever since.

• Mechanisms: There are plenty of mechanisms documented in which PUFAs contribute to all kinds of mayhem, including obesity, diabetes, heart disease, and more. We have these in the short-term, e.g. 4-HNE, a lipid oxidation end product of linoleic acid, stimulating the endocannabinoid system and giving you “the munchies.” We have them in the longer term, e.g. mitochondrial walls built with oxidized PUFAs being unable to maintain the energy gradient necessary for full function. And we have many more.

• Anecdotes: Plenty of people on Twitter and r/saturatedfat report results that seem incredible, if I hadn’t experienced many of them myself.

• Small crazy internet diet trials: You know what the ex150 trial, the potato diet, the Glass Noodle Diet trial, the most successful half-tato trialist, and many of the most successful people on the potato riff, had in common? You guessed it right: avoiding PUFAs.

Until somebody makes a better case..

Maybe something else about ex150 is doing all these magical things. It might just be the protein restriction. It might be heavy cream is magical. It might be reducing vegetables really helped. Who knows, maybe the trick is to alternate tomato & alfredo sauce.

But until somebody comes up with a hypothesis that fits the data better, I’ll stick to cutting out all the seed oils.

And even then? What would I gain? Oh great, I can eat fried chicken again. French fries at McDonald’s. Do I really miss those? Absolutely not.