I am always suspicious of mono-factorial explanations of any complex phenomenon, whether it be obesity or climate change. Yet for any such phenomenon there seems to be a population of people, call them philosophical monists, who stridently insist that the sole explanation for A must be B and B alone, and that anyone who claims otherwise or cites contrary evidence is in the pocket of Big B.
I think it’s important to distinguish between processed foods and *highly* processed foods. Even hunter gatherers used fire to cook meat to make it easier to chew and digest. Potatoes would kill you if eaten raw, so we cook them in all kinds of ways to make them safe, edible, and (most importantly) delicious. Avoiding foods that are processed in any way is basically a raw food diet, and I don’t think there’s any conclusive evidence that this is optimal for human health. Hunter gatherers were certainly lean, but they also very likely suffered long periods of nutrient scarcity, which (probably) took a toll on their lifespans. That said, I try to be mindful of my vegetable oil consumption and prefer to use less “processed” alternatives as often as I can. My wife’s fried chicken is just too damn good to pass up.
Great write-up! Now, can you do a follow-up on the "ultra processed food" craze?
This sounds like the latest and greatest nutrition ultra-mega-boogeyman.
In other words, is "ultra processed" really just a shortcut for "eat better qualify food"? Or is it really, truly about the "ultra processing?" (I suspect the former)
Drilling down a bit more, I'm curious about the dynamics of processed meats. Yes, there are damning studies. Yes, nitrates seem not good. But one can get no-nitrate processed meats. Is that OK? But, no, they're heavily salted! That's bad, right? But, wait! New views on existing studies appear to indicate that salt (like cholesterol) may be a victim of correlation vs. causation.
The entire field of nutrition seems to be creating/caught up in a bit of a crisis.
I appreciate this. I, too, have recently gone down a seed oil rabbit hole. There's a lot of enthusiasm and a lot of (very motivating) good results, but the causal factors remain quite unclear.
From Hannah Rithcie's Most Excellent "Not the End of the World"
Researchers at Harvard University have loudly pushed against this backlash. A meta-analysis covering 30 studies found that omega-6s lowered the risk of heart disease: those with more in their bloodstream were 7% less likely to develop
Another study followed around 2,500 men for an average of 22 years, and found that those with the highest blood levels of omega-6s had a much lower risk of dying from any disease. Studies show that they lower cholesterol and blood sugar. And the American Heart Foundation found that getting 5% to 10% of your calories from omega-6s reduces your risk of heart disease.
I've been following this debate for some time and I've landed in a similar place. My bird's eye takeaway for dietary wisdom has slowly coalesced into something like a smattering of loosely-related Rule of Thumb heuristics:
1. Don't drink your calories; instead, drink almost exclusively water
2. Eat mostly ingredients; avoid foodstuff with inscrutable origins
3. Refined carbohydrates, sugar and trans fats are on the naughty list
4. Err on the side of low-carb, err towards higher protein consumption
5. Don't eat gluten if you've got IBD (or any of the associated/adjacent conditions)
6. Prebiotic, soluble fiber might be good for you, but most fiber probably isn't
I grew up in a household that demonized mainstream medicine and lionized Dr. Oz, and since then I've had to eat a lot of crow as my personal investigations have overturned my previously unexamined beliefs, handed down by my parents; such subjects as iodized salt, fluoride in toothpaste and tap water, psyllium husk as a dietary supplement, colloidal silver and other homeopathic remedies that my mother/grandmother used to proselytize.
Probably the most contentious of the numbered list above are numbers five and six, both of which should be considered /strong opinions held loosely/ because they are based mostly on personal anecdote. I've had gastrointestinal issues since I was born, but I wasn't given an official diagnosis of IBD 'til well into high school, and it took them another decade to upgrade that diagnosis to full-blown Ulcerative Colitis. I've been through several phases of wacky self-experimentation, but my condition has been perfectly under control for the past five years now. And this is AFTER it had gotten so bad that I was pretty sure I'd be facing down a colectomy. The things that had the most tangible impact were FMTs (mostly this was a one-and-done sorta deal), cutting gluten completely out of my diet (I have since reintroduced gluten in very small, occasional amounts and it no longer triggers immediate adverse affects although it's still not pleasant) and avoiding fiber almost entirely.
Staying inquisitive, skeptical and genuinely oriented towards the truth has made all the difference. The heuristics that I listed above could be inverted if I discovered strong enough evidence, although the overall trajectory of my gut health has weighted my priors down pretty heavily in some regards. You've done an unusually good job capturing just how difficult it is thinking about diet, since it's almost impossible to have anything resembling a complete picture. I've tried to keep the odds of harm/benefit on the correct sides of the Pareto Principle where my takeaways are concerned, but quite likely I'm just plain wrong about something.
I think you've debunked it well enough. If you need to look TOO hard, you'll find what you're looking for because you get sloppy (as shown by your GDP data). The correlation that is easier to see is with "highly processed foods," meaning vending machine stuff, packaged muffins, that sort of thing. Obesity skyrocketed in Mexico after NAFTA made it possible to import said junk food in large, inexpensive quantities. I'll add this separate point: palm oil use is decimating jungles in Indonesia and other places, where jungles are being cut down for palm plantations. So... choose your (or the Earth's) poison.
Nice write-up. What is your source for the linoleic acid % in body composition over time? That's a very striking graph, but I'd like to know the source/methodology.
I have done a deeper dive on this than I care to admit, and where I landed was:
1. Olive oil and avocado oil are your best bet for everyday use in most applications.
2. Animal fats are okay *in moderation*. Don't go crazy. Avoid the non-animal highly saturated fats like coconut oil and palm oil.
3. Try to get some omega-3s. They are preferentially processed as compared to omega-6s, and the metabolic channel doesn't have infinite capacity. If you are processing omega-3s, you aren't processing omega-6s.
4. Avoid seed oils to the extent possible. But there's no need to be a zealot. Have some chips and queso when you're at the Mexican restaurant. It will be okay. There isn't a really good reason to believe that low level PUFA intake results in increased risks.
In practical terms, the regimen above is fairly conventional advice on diet (avoid junk food and eat lean proteins and vegetables and olive oil...Who knew??), and the downside risks seem to be slim to none.
My working theory is, more or less, PUFA intake above a certain threshold can interact with other diet and lifestyle factors to result in metabolic dysfunction that can cascade in lots of negative directions. It's tough to evaluate it all because, from an empirical perspective, the systems are absurdly complex and multi-variate and also because the impact of the hypothesized metabolic dysfunction is more in the way of long term chronic issues (diabetes, obesity, increased inflammation / cancer, etc.), whereas the benefits of replacing bad saturated fats with PUFAs is in the form of acute harm reduction (avoiding strokes, heart attacks, etc.).
The origin of schools of thought like the seed oil one are pretty fascinating. Like why did people skip by the more straightforward stuff like calories in and out, glycemic index, highly palatable food, and nutrients? I mean, I guess I know the answer - it's because the basic answers are kind of boring and it's much more fun to have access to special knowledge that makes you special and also presents a workaround to boring stuff like eating less. And sometimes the special knowledge turns out to be true.
Overall, I guess I'm glad that we have people going off on weird tangents like seed oils, lithium in the water, and potato diets, but most of the time they're going to come to nothing. They're very low probability, high payoff bets.
I also continue to be amazed by how hard it is to really know anything in epidemiology. We've done, what, 30/50/100 studies on seed oils? And the answer we come out with after careful consideration for what seed oils do is, "Hmm, not quite sure, probably nothing in particular." I guess that's just how it is, but sometimes it makes me laugh/cry.
Great post, but isn’t using BMI for global comparisons problematic due to between-race variance in how well it correlates with obesity/bad health outcomes?
On the wider and more interesting question of "what went wrong", I agree that singe-cause explanations are not very believable. But in very broad terms, in the last century or so humanity has been hyper-optimizing all sorts of things. From capital usage, competition and advertising, to land yields and fabrication recipes, everything is now hyper optimized, or it just can't compete in the mainstream. Not to idealize or simplify the past too much, but nothing used to be so relentlessly optimized. Cultures would vary from one place to the next instead of being all in contact and competition, innovation was slow, expectations were much lower, and there weren't just that many people around to be fed and sold to.
And what happens in a dynamic system when you optimize for a subset of parameters, is that the *rest* of the parameters just jump around randomly. If there was some kind of cultural selection pressure keeping them within some bounds, it gets overwhelmed and is no longer operative.
So I'm not surprised that the result is what some people nowadays call a "polycrisis". Everything that isn't being directly optimized for by the economic system is just slowly going out of whack, from the Earth's climate to our physical and mental health, to the sanity of cultural output. It's Cory Doctorow's enshitiffication, but on the broadest scale.
And on the practical terms of "what can I do with the moderate amount of effort that I'm willing to put on this", I basically agree with Dynomight and other commenters' suggestions. At home we just use cold-pressed olive oil for everything; it's not some hard won virtue over here in Spain, it's just what my parents and their parents used to do, we're lucky the this particular continuity didn't get broken. Drink mostly water or teas (herbal or regular), eat plenty of vegetables, etc. And for home usage I try to avoid stuff with ingredients someone's great grandma wouldn't recognize - we get enough of that shit when eating out.
Thank you for that excellent analysis.
I am always suspicious of mono-factorial explanations of any complex phenomenon, whether it be obesity or climate change. Yet for any such phenomenon there seems to be a population of people, call them philosophical monists, who stridently insist that the sole explanation for A must be B and B alone, and that anyone who claims otherwise or cites contrary evidence is in the pocket of Big B.
this is cool and interesting! thank you.
I think it’s important to distinguish between processed foods and *highly* processed foods. Even hunter gatherers used fire to cook meat to make it easier to chew and digest. Potatoes would kill you if eaten raw, so we cook them in all kinds of ways to make them safe, edible, and (most importantly) delicious. Avoiding foods that are processed in any way is basically a raw food diet, and I don’t think there’s any conclusive evidence that this is optimal for human health. Hunter gatherers were certainly lean, but they also very likely suffered long periods of nutrient scarcity, which (probably) took a toll on their lifespans. That said, I try to be mindful of my vegetable oil consumption and prefer to use less “processed” alternatives as often as I can. My wife’s fried chicken is just too damn good to pass up.
Great write-up! Now, can you do a follow-up on the "ultra processed food" craze?
This sounds like the latest and greatest nutrition ultra-mega-boogeyman.
In other words, is "ultra processed" really just a shortcut for "eat better qualify food"? Or is it really, truly about the "ultra processing?" (I suspect the former)
Drilling down a bit more, I'm curious about the dynamics of processed meats. Yes, there are damning studies. Yes, nitrates seem not good. But one can get no-nitrate processed meats. Is that OK? But, no, they're heavily salted! That's bad, right? But, wait! New views on existing studies appear to indicate that salt (like cholesterol) may be a victim of correlation vs. causation.
The entire field of nutrition seems to be creating/caught up in a bit of a crisis.
I appreciate this. I, too, have recently gone down a seed oil rabbit hole. There's a lot of enthusiasm and a lot of (very motivating) good results, but the causal factors remain quite unclear.
TY for this, especially the Distraction part.
From Hannah Rithcie's Most Excellent "Not the End of the World"
Researchers at Harvard University have loudly pushed against this backlash. A meta-analysis covering 30 studies found that omega-6s lowered the risk of heart disease: those with more in their bloodstream were 7% less likely to develop
Another study followed around 2,500 men for an average of 22 years, and found that those with the highest blood levels of omega-6s had a much lower risk of dying from any disease. Studies show that they lower cholesterol and blood sugar. And the American Heart Foundation found that getting 5% to 10% of your calories from omega-6s reduces your risk of heart disease.
I've been following this debate for some time and I've landed in a similar place. My bird's eye takeaway for dietary wisdom has slowly coalesced into something like a smattering of loosely-related Rule of Thumb heuristics:
1. Don't drink your calories; instead, drink almost exclusively water
2. Eat mostly ingredients; avoid foodstuff with inscrutable origins
3. Refined carbohydrates, sugar and trans fats are on the naughty list
4. Err on the side of low-carb, err towards higher protein consumption
5. Don't eat gluten if you've got IBD (or any of the associated/adjacent conditions)
6. Prebiotic, soluble fiber might be good for you, but most fiber probably isn't
I grew up in a household that demonized mainstream medicine and lionized Dr. Oz, and since then I've had to eat a lot of crow as my personal investigations have overturned my previously unexamined beliefs, handed down by my parents; such subjects as iodized salt, fluoride in toothpaste and tap water, psyllium husk as a dietary supplement, colloidal silver and other homeopathic remedies that my mother/grandmother used to proselytize.
Probably the most contentious of the numbered list above are numbers five and six, both of which should be considered /strong opinions held loosely/ because they are based mostly on personal anecdote. I've had gastrointestinal issues since I was born, but I wasn't given an official diagnosis of IBD 'til well into high school, and it took them another decade to upgrade that diagnosis to full-blown Ulcerative Colitis. I've been through several phases of wacky self-experimentation, but my condition has been perfectly under control for the past five years now. And this is AFTER it had gotten so bad that I was pretty sure I'd be facing down a colectomy. The things that had the most tangible impact were FMTs (mostly this was a one-and-done sorta deal), cutting gluten completely out of my diet (I have since reintroduced gluten in very small, occasional amounts and it no longer triggers immediate adverse affects although it's still not pleasant) and avoiding fiber almost entirely.
Staying inquisitive, skeptical and genuinely oriented towards the truth has made all the difference. The heuristics that I listed above could be inverted if I discovered strong enough evidence, although the overall trajectory of my gut health has weighted my priors down pretty heavily in some regards. You've done an unusually good job capturing just how difficult it is thinking about diet, since it's almost impossible to have anything resembling a complete picture. I've tried to keep the odds of harm/benefit on the correct sides of the Pareto Principle where my takeaways are concerned, but quite likely I'm just plain wrong about something.
Thanks for another solid article, Dynomight.
I think you've debunked it well enough. If you need to look TOO hard, you'll find what you're looking for because you get sloppy (as shown by your GDP data). The correlation that is easier to see is with "highly processed foods," meaning vending machine stuff, packaged muffins, that sort of thing. Obesity skyrocketed in Mexico after NAFTA made it possible to import said junk food in large, inexpensive quantities. I'll add this separate point: palm oil use is decimating jungles in Indonesia and other places, where jungles are being cut down for palm plantations. So... choose your (or the Earth's) poison.
Nice write-up. What is your source for the linoleic acid % in body composition over time? That's a very striking graph, but I'd like to know the source/methodology.
I have done a deeper dive on this than I care to admit, and where I landed was:
1. Olive oil and avocado oil are your best bet for everyday use in most applications.
2. Animal fats are okay *in moderation*. Don't go crazy. Avoid the non-animal highly saturated fats like coconut oil and palm oil.
3. Try to get some omega-3s. They are preferentially processed as compared to omega-6s, and the metabolic channel doesn't have infinite capacity. If you are processing omega-3s, you aren't processing omega-6s.
4. Avoid seed oils to the extent possible. But there's no need to be a zealot. Have some chips and queso when you're at the Mexican restaurant. It will be okay. There isn't a really good reason to believe that low level PUFA intake results in increased risks.
In practical terms, the regimen above is fairly conventional advice on diet (avoid junk food and eat lean proteins and vegetables and olive oil...Who knew??), and the downside risks seem to be slim to none.
My working theory is, more or less, PUFA intake above a certain threshold can interact with other diet and lifestyle factors to result in metabolic dysfunction that can cascade in lots of negative directions. It's tough to evaluate it all because, from an empirical perspective, the systems are absurdly complex and multi-variate and also because the impact of the hypothesized metabolic dysfunction is more in the way of long term chronic issues (diabetes, obesity, increased inflammation / cancer, etc.), whereas the benefits of replacing bad saturated fats with PUFAs is in the form of acute harm reduction (avoiding strokes, heart attacks, etc.).
Have you reviewed the works of Fire in a bottle and the surrounding community? Lots of good meta research on this topic.
The origin of schools of thought like the seed oil one are pretty fascinating. Like why did people skip by the more straightforward stuff like calories in and out, glycemic index, highly palatable food, and nutrients? I mean, I guess I know the answer - it's because the basic answers are kind of boring and it's much more fun to have access to special knowledge that makes you special and also presents a workaround to boring stuff like eating less. And sometimes the special knowledge turns out to be true.
Overall, I guess I'm glad that we have people going off on weird tangents like seed oils, lithium in the water, and potato diets, but most of the time they're going to come to nothing. They're very low probability, high payoff bets.
I also continue to be amazed by how hard it is to really know anything in epidemiology. We've done, what, 30/50/100 studies on seed oils? And the answer we come out with after careful consideration for what seed oils do is, "Hmm, not quite sure, probably nothing in particular." I guess that's just how it is, but sometimes it makes me laugh/cry.
Great post, but isn’t using BMI for global comparisons problematic due to between-race variance in how well it correlates with obesity/bad health outcomes?
On the wider and more interesting question of "what went wrong", I agree that singe-cause explanations are not very believable. But in very broad terms, in the last century or so humanity has been hyper-optimizing all sorts of things. From capital usage, competition and advertising, to land yields and fabrication recipes, everything is now hyper optimized, or it just can't compete in the mainstream. Not to idealize or simplify the past too much, but nothing used to be so relentlessly optimized. Cultures would vary from one place to the next instead of being all in contact and competition, innovation was slow, expectations were much lower, and there weren't just that many people around to be fed and sold to.
And what happens in a dynamic system when you optimize for a subset of parameters, is that the *rest* of the parameters just jump around randomly. If there was some kind of cultural selection pressure keeping them within some bounds, it gets overwhelmed and is no longer operative.
So I'm not surprised that the result is what some people nowadays call a "polycrisis". Everything that isn't being directly optimized for by the economic system is just slowly going out of whack, from the Earth's climate to our physical and mental health, to the sanity of cultural output. It's Cory Doctorow's enshitiffication, but on the broadest scale.
And on the practical terms of "what can I do with the moderate amount of effort that I'm willing to put on this", I basically agree with Dynomight and other commenters' suggestions. At home we just use cold-pressed olive oil for everything; it's not some hard won virtue over here in Spain, it's just what my parents and their parents used to do, we're lucky the this particular continuity didn't get broken. Drink mostly water or teas (herbal or regular), eat plenty of vegetables, etc. And for home usage I try to avoid stuff with ingredients someone's great grandma wouldn't recognize - we get enough of that shit when eating out.
Saturated fat has no effect on overall mortality according to the meta
https://sci-hub.se/10.1002/14651858.CD011737.pub3