SlimeMoldTimeMold (Who's article series the Contamination Theory paper is based on) has wrote a post about the seed oil hypothesis. They also cover Jeff Nobbs' series.
Excerpt from the end
The literature on seed oil consumption in humans consistently shows that seed oils cause no more weight gain than other fats. When we took a closer look at some of these studies, we found serious problems with several of the analyses. The evidence here is weak at best.
This doesn’t mean that seed oils, or vegetable oils, or whatever you want to call them, are good for you. They may still be very bad for you, and the case for other health effects (including a connection with cancer) seems stronger. But it doesn’t look like they could be a major cause of the obesity epidemic, and probably, they play no role at all.
How do you reconcile your theory with the fact the vegans are slimmer than omnivores by a large margin? They supposedly changed all animal fat for vegetable oil.
No clue, that would be a tough data point, taken as given that they got skinnier while also using more vegetable oil. I don’t know much about vegans so I’ll look into it, if you had to steelman it what would you say?
Perhaps they switch to oils relatively better for our health such as olive oil. My cursory googling points to this as a possibility.
Fighting the strongest version of this argument: let’s say someone does lose weight replacing meat with lots of soybean oil. If soybean oil primarily induces us to eat more, then veganism counteracts it by vastly reducing the choice set of palatable food, coming out slightly net positive for losing weight. In this scenario you’d expect veganism to be very, very hard to stick to assuming you add a lot of vegetable oil to your diet. In this scenario, veganism would have no special sauce vis a vis other diets, and would actually be a pretty uphill battle to lose weight.
Overall, my arguments would still leave a lot to be desired, the existence of healthy vegans chowing down on vegetable oils would certainly be a net negative for the plausibility of this theory
I could well imagine that there are there are strong selection effects at play (more health-concerned people being more likely to give veganism a shot), and the positive effects of the diet just outweighing the possible slight increase in plant oil usage. And I wouldn't even be so sure if vegans on average consume more plant oil than non-vegans - e.g. vegans probably generally consume much less processed food, which is a major source of vegetable oil.
Theory: Olive oil is fine and vegans are more likely to cook their own food and so they take a higher olive oil to seed oil ratio than average.
It would also dovetail with the other mysteries: despite investigation we can't seem to figure out exactly why processed sugar seems so much worse for you than matched amounts from fruit and dairy. Similarly, despite investigation, we can't seem to figure out why highly processed protein is so much worse for you than non processed protein. My guess is that alterations to the molecular structure of substances winds up in a negative goldilocks zone: not altered enough that the body rejects it thus getting incorporated as functional structure (cell walls, say), but altered enough that some bio processes either don't work or work at significantly reduced efficiency or with weird side effects. This will eventually be measurable, we don't have the right proxy metrics currently.
Interesting, that would definitely jive with processed foods being bad. I think you could make a great argument that it’s more primarily processed foods too, vegetable oils included. Now in these findings, are they under isocaloric conditions? I ask because you could certainly posit that processed foods are bad because they avoid satiating us somehow, but that wouldn’t necessarily hold in situations where we get the same number of calories from them. I think that’s an easier hurdle to start with, it’s very easy to imagine structures in food that our body measures satiety with getting broken down under any type of processing, but your idea of reduced efficiency or side effects would be next on my list after that.
what constitutes a processed protein here? I thought everything was getting broken down into amino acids anyway?
Processed protein is something that there isn't a great definition for precisely because our models are missing something. There's something about preserved and processed meats that does something bad but we don't know what.
Similarly we aren't sure why natural short chain carbs (honey, high GI fruits) seem to elicit less negative effects than processed short chain carbs. Our causal models are missing something.
Does it seem likely that soybean oil in particular is special? I think I could pretty straightforwardly eliminate it from my diet - I never cook with it and am not specifically attached to snacks that contain it - but I'd have a harder time if I also couldn't use canola, sesame, avocado, coconut... Let alone other soy products like tofu.
FWIW I mostly eliminated (>90% reduction) corn, soy, canola, and most other highly processed oils from my diet in January 2020. I kept or increased olive, avocado, coconut, some sesame and nut oils, and butter (from mostly-grass-fed cows). No idea about long term health impacts, but since about 6 months from that shift I've found that if I did eat those oils in significant quantities at a meal (especially things like battered fried food), I consistently notice substantial negative effects on mood, energy level, and nasal congestion, typically for the rest of the day. This does not happen if I eat the same foods made with other oils, nor if I eat actual corn, or other soy products like tofu.
Also: this change led to a bit of initial weight loss (from ~235 down to ~220), but that's mostly where I've stayed for the past 2.5 yrs. BMI says I need to lose another 40 pounds, but I disagree and haven't been that weight since I was 16. I would like to get down to ~195.
As for the other soy products, I have heard some concerns about the lectins, which are poisonous. Vegetables in general have toxins, which are usually there to protect them from insects. Humans, like most animals that eat plants, have adaptations to deal with this, so vegetables in general are not thought to be unhealthy, and probably not all of their effects are harmful, so I'm not sure what to make of this.
Most legumes, nuts, whole grains, and nightshades (e.g. tomatoes) contain a concerning amount of lectins, but cooking and fermentation can mostly break them down, and soaking and rinsing can also get rid of them. Most lectins break down with heat, but those found in peanuts and soybeans seem to be an exception, and might explain why allergies to these two foods are so common. Maybe some types of lectins are harmful and others are not, at natural doses.
I'm also suspicious of canola, but avocado and coconut oil have very different properties from soybean oil.
Canola is from recently developed cultivars of rapeseed, is high in pro-inflammatory omega-6 polyunsaturated fat, which also oxidizes (becomes rancid) more easily, and since canola is usually extracted with solvents and heat, it usually contains some amount of very unhealthy trans fats. This gets worse if you cook with it. If your only goal was to avoid saturated fats, then it sounds good on paper, but it's probably bad for you.
Sesame is a seed oil like canola. It's even higher in omega-6. Sesame oil tastes fine when cold-pressed, so trans fats would be less of a concern in that case. It's probably still bad for you overall.
Coconut oil is mostly saturated fat. It's resistant to oxidation, shouldn't contain trans fats, and is safe to fry with. Are saturated fats bad for you though? Some say so, but I'm not sure if I believe them.
Avocado oil is mostly monounsaturated fat, which isn't the supposedly unhealthy saturated fat, and is more resistant to oxidation and heat than polyunsaturated fat, though not as resistant as saturated fat. It should be safe too cook with as long as you're not using high heat. Its composition is actually really similar to olive oil. If you're going to add oil at all, avocado oil is probably one of the healthiest choices. Olive is good too for the same reasons, but it might have additional beneficial compounds when it's fresh.
Jeff Nobbs (one of OP's sources) says polyunsaturated fatty acids are the real culprit and provides a helpful chart. Tl;dr coconut oil is great, olive and avocado oil are pretty good, avoid canola/peanut/rice bran/corn/sunflower. (Sesame isn't on the chart but IME it's used in pretty small quantities anyway).
It's hard to get much oil from whole versions of the source foods. My quick calculation say you can add '5 tbs soybean oil requires six blocks of tofu'.
Soybean oil grew the most in the USA, and some studies in mice make it look quite bad. I’m not positive, but my takeaway is that it is very low downside and quite easy to cut it out of my diet. On the one hand it is new, and our ancestors were fine without it, whether it is bad or not. And two, it’s highly concentrated in processed junk that everyone agrees to avoid anyways. As for general soy products, not my area of expertise but I’m not going out of my way to avoid them if they’re not highly processed
it’s highly concentrated in processed junk that everyone agrees to avoid anyways.
One hypothesis I heard recently is that most natural whole foods are either high in both fiber and carbohydrates (vegetables), or in both fat and protein (animals), but the combination of fat+carbs without the fiber and protein is common in processed foods, which results in much less satiety per Calorie. The whole foods, on the other hand, are much harder to overeat. This explains why both low-carb and low-fat diets work: they both cut out the fat+carbs junk foods.
Butter your steak, not your potatoes?
So it may be the recent addition of cheap seed oils to our staple carbohydrates that explains most of our problem. That's just a hypothesis though. I really don't understand what's happening.
I don’t think anyone does! Now nature isn’t always right, but I tend to think you need a good reason to deviate from it. Something about the primarily processed foods is killing us en masse. I tend to think it’s acting mainly along some satiety axis, as otherwise your body should adjust towards a healthy homeostasis, but in many it isn’t. People are being given a signal to eat in excess of what’s healthy—quite literally killing them, and they seem unable to do anything about it in the long run of their own accord. Does that point to damage in the hypothalamus, a change in hormones, or are some highly processed foods simply sneaking through the gates? I don’t know. As for your theory, I find it interesting—people really seem to agree that processed foods are bad, and some are only processed to the extent that a few components are consumed separately. If two components are inextricably tied for all of human history, the body would only need to measure one to get a good idea of where it stands. Certainly something to think about. What would have to be true for that theory to be true? Well, it should be really hard to overconsume protein to gain weight, but quite possible to become overweight primarily with fat. Easy to get fat on white bread, hard to get fat on vegetables high in fiber. Easy on cheese, hard on eggs. But why does our brain love this energy injection when we are positing that it can’t measure it? Perhaps it can’t measure it well, all you need is for it to be a little off to the tune of about 3600 calories a year. But why wouldn’t it be able to just measure the amount of fat and downgrade appetite? Well, we’ve already established that we’re talking about only a pound a year in the average American, that could be kept up as a continuous process—you could do that in two days relatively easily. That simple mental experiment definitely sets off some bells though
One thing that jumped out at me from the [Stephan Guyenet post](http://wholehealthsource.blogspot.com/2011/08/seed-oils-and-body-fatness-problematic.html) Scott cites: the increasing linoleic acid content of human fat.
Mostly I'm intrigued because I've basically never heard anyone talk about body fatty acid composition before at all. For all I knew, the human body converted all its fats into a standardized human fat before storing them.
And this kinda seems like a big deal, just intuitively? It definitely makes me update in favor of vegetable fat consumption having some kind of cumulative effect.
Good stuff, I'm still digesting it all! This adds to my idea that different types of oils/fats and different types of w3 and w6's act quite differently in studies. I see very little bad about olive oil, and virtually nothing about soybean oil in particular even though it's used most intensively in the US. People tend to talk of them in monolithic ways, but when you get down to it something like olive oil almost always stacks up well. As for the intuition, same here, not sure what to really make of this stuff other than it I don't see a downside to excluding seed oils from my diet--our ancestors were certainly fine without them, and they're found mainly in processed foods. The other low downside takeaway I have is that this should be studied more. When zoomed out, it definitely looks like a preponderance of the evidence is against seed oils, but when you get lost in the really specific studies you always come away thinking that whatever pathway they chose wasn't quite proven.
Also, re: China being an outlier of high vegetable oil intake with low obesity, apparently soybean oil has been used there for millennia. Adaptation?
Obesity rates in China are rapidly rising, I doubt that there is a strong corresponding increase in soybean oil.
https://www.indexmundi.com/agriculture/?country=cn&commodity=soybean-oil&graph=domestic-consumption
These guys say yes
https://www.statista.com/statistics/946501/china-soybean-oil-consumption-volume/
These guys say not really
Haven't started playing with time series data yet, you may be interested to know that there is something fundamentally different about the patterns of consumption between Asian countries and GDP--that is to say there is no correlation in my data, but a very strong for Ex-Asia and GDP
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212740
Very interesting, that could give us a pretty good test case. At first blush, it rings as consistent with this theory. However, it seems the Chinese in the USA are more obese than in China, but not as obese as white or black or Latino Americans (they still have plenty of time to catch up). That would imply:
Or something else, but that evidence is somewhat hard to rectify with soybean oil completely causing all this. On that macro level, just comparing USA obesity to China obesity, that could explain a lot. When I think about Chinese in the USA, it comes a little undone. There is plenty of precedent in racial differences in reaction to foods, such as dairy and alcohol.
Japan is interesting:
https://www.indexmundi.com/agriculture/?country=jp&commodity=soybean-oil&graph=domestic-consumption
Consumption falls between 06 and now, as does obesity in boys
And this is quite interesting too, but doesn’t entirely support our theory, it’s hard to tell what the trend is there. If it’s trending up, you’d have to posit that the oil only modulates obesity in young people, which isn’t the most ridiculous idea ever, however it would be another hurdle.
https://twitter.com/kevinnbass/status/943719131181920256?s=20
Overall, Japan seems to somewhat vindicate our idea here, that is really quite striking that obesity and soybean oil decline at the same time in boys, and I think overall obesity looks to have flatlined in adults in that timeframe. Also, they mostly missed the obesity train despite being industrialized relatively early on; due to their adaptation.
Any other thoughts? I definitely feel like I haven’t quite thought this through quite right logically, or I’m missing something. Thanks for the new info.
Thanks for pulling all that data!
That study says third-generation Chinese-Americans—presumably the ones eating the most typically American diet—are actually slightly more obese than white Americans! At face value that pretty much torpedoes any genetic adaptation theory (and I have no particular reason not to take it at face value).
Theories 1 and 2 are both quite possible.
Re: Japan, it looks like soybean oil doesn't dominate vegetable oil intake like in the US; rapeseed is more common and did not decline in the same way, and palm oil is also significant, so their overall trend in vegetable oil consumption isn't so easy to eyeball. Though I think those numbers are consumption in the economic sense, not in the 'eating' sense—not sure how to account for that.
Ah interesting, nice catch there. Wonder what's going on with 3rd gen Chinese, given that the equivalent all Asian is .86 whites vs their 1.08.
though 2nd and 3rd generations of Asians were also associated with reduced obesity prevalence as compared to other races, the magnitude of the association decreased compared to the 1st generation of Asians.
So in aggregate, it would lend itself a bit to our theory here
Also, you may be interested to know that there is no correlation between consumption and GDP in Asian countries, while Ex-Asia GDP is very highly correlated. I noticed the difference just eyeballing the chart in the OP--at the very least the linkage between GDP and consumption is fundamentally different between Asia and Ex-Asia. When you separate the data you start getting other really interesting stuff too, I'll definitely be putting that on my substack soon.
Either way, I don't put an absolutely massive amount of stock in this, but it is certainly plausible, I was reading this article:
https://pubmed.ncbi.nlm.nih.gov/24977108/
So we would be getting closer to a mechanism--there is a genetic difference between African Americans and
(FADS) cluster are determinants of long chain polyunsaturated fatty acid (LC-PUFA) levels in circulation, cells and tissues.
Can't find a lot of stuff on Asians or Asian Americans.
Re: Japan
Yeah, I haven't had time to really dig into how intake differs between countries; one of many reasons why I didn't put much stock in the data I gathered. The best numbers are consumption, but it is really hard to figure out what exactly that entails when it comes down to calories in bodies.
Some of the other top causes of obesity include endocrine disruptors, Adenovirus-36, antibiotics (especially in childhood), C-sections, foods that spike blood sugar (carb-heavy), certain medications (antipsychotic drugs, anti-depressants, steroids, birth control)
Whatever the cause is, I’d bet it’s probably modulated by genetics as well. The Peery paper goes into it too. I have most of those factors other than maybe the virus and I pretty effortlessly maintain a 22 BMI unless I’m drinking 5+ beers a day for months. Obviously anecdote but I know I couldn’t get down to 18 BMI without a ton of effort, just as an obese person can’t get down to 23 without a ton of effort too. Or perhaps the damage is done as a child or in the womb, hard to say.
This is definitely an interesting topic, and I too would like to see a continued discussion as well as more research in the area. I also think that Jeff Nobbs' articles are not a great source, as he seems to twist the facts quite a bit in order to support his theory. This is particularly the case for part 2 of his series - looking into practically any of the linked studies, I found issues with how he summarized them. Some examples:
(note I wrote this up from memory, so possible I've mixed something up in the examples above - might be worth writing a post about it with properly linked sources)
I still think he's probably right about many things, and it's most certainly correct that oils high in Omega6 in particular aren't healthy (which might indeed include Canola oil, which I was not aware of before reading his articles). Still he seems to be very much on an agenda to an extent that it prevents him from summarizing studies accurately, which is not great. Doesn't mean he's wrong, but also means I won't trust anything he says without checking the sources.
Suppose someone wrote an essay that sought to uncover the cause of climate change. Admitting that the explanation may be multiplex, they mention automobiles, TVs, and light-bulbs. "Any of these could be the real explanation for why the globe has warmed," they explain, "but personally, my bet is on automobiles," before laying the striking correlation between automobile adoption and global temperature.
Now you check and—indeed—they never once mentioned the role of greenhouse gasses, which is the factor connecting all of the candidate causes together. In that case, I would be quite exasperated by such an essay, as it would seem to distort, rather than clarify, the underlying mechanism driving climate change.
Similarly, I am exasperated by this essay in your neglect to mention the role of calories. We have overwhelming evidence that weight is determined directly by caloric intake and energy expenditure. There are, of course, sensible questions pertaining to how much of one's weight can be explained these factors, but no doubt about whether the answer is at least "a great deal."
The simple theory, as in the case of climate change, would begin by identifying how any potential cause connected to caloric intake and energy expenditure. Now, I may have missed something, but I did not see you do this. From the point of view of someone who already understands this background mechanism well, perhaps this omission makes sense. But as a casual reader, I didn't quite understand why you believed this theory to be plausible.
I find the "Calories In, Calories Out" paradigm really exasperating. It may be technically correct, but it's a red herring, useless in practice, because it completely misses the real issue.
The body has a multitude of feedback mechanisms to maintain homeostasis. Weight is usually pretty stable. If you exert willpower to count calories and eat fewer of them, then the predictable response of the body is to reduce energy expenditure and to become hungrier. Neither is pleasant.
The mistaken mainstream scenario goes like this: You have sinned. You've been a glutton, but just a little bit. Occasionally, over the years, you've indulged yourself in the pleasures of eating and had just a bit too much. But a little here and a little there adds up over the decades and now you're definitely overweight!
Calories In, CaIories Out. But exercise seems to barely burn more than breathing, unless you're literally running marathons, so it's really just about Calories In.
So, if you want to lose the excess weight, then you simply have to Eat Fewer Calories. Ultimately, that's the only way any diet can work. So let's try the direct approach: fasting two days in a row per week will do it. (You can still have water, which has no Calories.) Couldn't be simpler. You exhaust your glycogen stores the first day, so your body has not choice but to switch to burning fat on the second. (Fasting for even longer periods works even better, but there are risks. 48 hours is perfectly safe unless you've got a weird medical issue. People do it religiously all the time.)
Continue until you're back to normal weight. Problem solved, right? Just do it again in a few decades when your gluttony catches up with you again. Right?
Except it doesn't work like that.
If you try this, and you're not already so overweight that you fail to sustain the program to hit your target, then when you stop you'll probably gain most of it back within a year. Not the decades it took you in the first place. If you're sufficiently overweight, then you'll lose some, but then gain enough of it back each week between fasts that you stop making progress.
Why?
Somehow the body's homeostasis program for weight got out of whack. That's the real issue. That's the part I'm interested in. Not the guilt/repentance cycle, because that never works. If things are working properly in the first place, then when you indulge, you have more energy and are less hungry. Homeostasis! For normal, healthy people, gaining weight seems to be as hard as losing it!
Why did the "set point" go up, permanently? Why don't you just get more fidgety and burn it off? Why don't you just get less hungry for your next meal? I don't fracking know.
There are a lot of interesting hypotheses. Maybe it's the fats. Skim the milk! Go vegan! Except whole milk works better for weight loss. Maybe it's the carbs. Atkins/Keto/Carnivore. /Paleo? No vegan! Maybe it's only both at once? Maybe it's the excess fructose building up fat in your liver. Maybe the antibiotics killed off an important strain in your gut flora, and no diet can work until you get it back. It's a ratchet. Maybe it's the emulsifiers emulsifying your gut lining, causing irritation. Maybe it's the omega-6, causing inflammation. Maybe it's just the ratio with the omega-3? Moar fish! Except mercury. Less fish! Maybe it's the high–glycemic index foods causing insulin spikes causing insulin resistance. Maybe it's the low–glycemic index foods not causing spikes not causing satiety. Maybe it's just not enough fiber. Moar beans. Grains must be made Whole. Maybe it's the lack of fiber that killed off the strain (and no diet can work until you get it back). Would fermented foods help? Some other probiotics? Which ones? Maybe it's mysterious chemicals in our packaging. Could be the plasticizers? Preservatives? Pesticides? Maybe it's the lectins. Beans are bawal. No moar beans. Grains are unWholy. Don't get me started on all the deadly nightshades. In fact, all the New World Plants are a Paradox. Unless you're Latino. GMOs are perfectly safe! Except they sometimes add pest-resistance, I mean "natural" pesticides, I mean lectins. Oops. Unless you cook them. Unless they're soybeans. Or peanuts. Other nuts must be roasted. Other gurus will be roasted too. Because they're nuts. It's a racket. And that A1-casein looks suspiciously lectin-like. You need special organic cows instead. Or switch to goat milk. It's the only way to be sure.
I am not making this up. I have evidence for all of this.
I notice I am Confused about this. No, I am very confused about this. So is everyone else. I think the global warming metaphor has thoroughly broken down. It's like when no-one knew what was causing scurvy and thought vitriolic elixir, vinegar, or seawater might help. We are that confused about this. No-one knows what the hell is going on, and even if they do, I've got ten more hypotheses that sound just as plausible. And have studies. That maybe haven't been replicated. Le sigh.
I notice I Am Confused about this. So are you.
Never be too sure.
I don't think I can respond to everything in your comment, but let me try to address the main point. As I understand, you say that something is left unexplained by the "Calories in, Calories out" paradigm. That something is explained by your question,
Why did the "set point" go up, permanently?
I think the most likely explanation is simply that modern food is tastier than the more bland food eaten in the past. "Taste" here should be interpreted as capturing all dimensions of the satisfaction of eating, including texture, mouthfeel, and aftertaste. There is also a simple explanation for why typical food has gotten tastier over time; namely, food science has gotten better, corporations have become more efficient at producing and marketing processed foods, and consumer incomes have gotten higher—thus enabling more access and greater choice.
This explanation also perfectly predicts your long paragraph addressing possible causes. Is it fat? Carbs? High-glycemic index foods? Not enough grains? I ask: why couldn't it be all those things at once?
If the reason why we eat more is because food has gotten tastier, then we should also expect the "cause" to be multifaceted. After all, most people don't think that there's only "one thing" that makes food taste good. Taste is more complicated than that, and varies between people.
Reducing the question of "why are we getting obese?" to "why do foods taste good?" doesn't solve the problem, of course—we still don't have a full theory of why food tastes good. But, in my opinion, if it's correct, then it totally deconfuses the proximate mechanism here.
In that sense, I think my CO2 analogy holds quite well. There are many reasons why people omit CO2: electricity, temperature control, transportation etc. And as we've gotten richer, those justfications have become more salient, as people can afford to purchase service that provide those benefits, omitting CO2 as a byproduct. Simply knowing this doesn't mean you've solved climate change, of course, but it gets you a lot further than "Why are people burning more CO2 than before? I don't know; could be anything."
I think that analogy maps quite well. In both cases we have a net retention of energy--measured in temperature on earth and in weight in humans. I believe there's the possibility that I'm writing about the metabolic equivalent of CO2 in humans here (both graphs go up and to the right with industrialization). See, we know that the net balance of calories in humans or joules retained on earth is going up. The question is why. I think the answer to "why" is CO2/possibly vegetable oils. As for "how," from what I understand that is the source of your exasperation--in climate change the answer to "how" is the greenhouse effect--the mechanism. What is it about these substances that cause the energy to be retained? As for this theory, there are a many reasons that I don't fully and completely understand, so I didn't want to muse on about them in the OP. I am certainly at fault for your exasperation here.
The following are studies (not an exhaustive list) followed by what I would consider the statements that most closely map to "mechanism"
Here is perhaps the most direct answer for weight gain
https://pubmed.ncbi.nlm.nih.gov/22334255/
Here we posited that excessive dietary intake of linoleic acid (LA), the precursor of AA, would induce endocannabinoid hyperactivity and promote obesity.
Here's one for inflammation, which from what I know is quite correlated with weight gain:
https://pubmed.ncbi.nlm.nih.gov/22570770/
Omega-6 (n-6) polyunsaturated fatty acids (PUFA) (e.g., arachidonic acid (AA)) and omega-3 (n-3) PUFA (e.g., eicosapentaenoic acid (EPA)) are precursors to potent lipid mediator signalling molecules, termed "eicosanoids," which have important roles in the regulation of inflammation.
Here's the really crazy study in mice:
https://pubmed.ncbi.nlm.nih.gov/31912136/
To test the hypothesis that soybean oil diet alters hypothalamic gene expression in conjunction with metabolic phenotype
https://pubmed.ncbi.nlm.nih.gov/26200659/
Metabolomics analysis of the liver showed an increased accumulation of PUFAs and their metabolites as well as γ-tocopherol, but a decrease in cholesterol in SO-HFD. Liver transcriptomics analysis revealed a global dysregulation of cytochrome P450 (Cyp) genes in SO-HFD versus HFD livers, most notably in the Cyp3a and Cyp2c families. Other genes involved in obesity (e.g., Cidec, Cd36), diabetes (Igfbp1), inflammation (Cd63), mitochondrial function (Pdk4) and cancer (H19) were also upregulated by the soybean oil diet. Taken together, our results indicate that in mice a diet high in soybean oil is more detrimental to metabolic health than a diet high in fructose or coconut oil.
And finally in terms I can really understand intuitively:
https://www.jeffnobbs.com/posts/why-is-vegetable-oil-unhealthy
The primary fatty acid in most vegetable oils is linoleic acid, a type of omega-6 fat. The omega-6 content of vegetable oils is what makes them so problematic.
Omega-6 fats, while necessary in extremely small amounts, contribute to general inflammation when eaten in excess. While chronic inflammation is cited as a source of many of the diseases we face today [1], it’s just the tip of the iceberg. The unstable, reactive properties of dietary omega-6 create a host of other downstream effects that have been causally linked to poor health and chronic disease, including heart disease, the leading cause of death in the world [2].
Now that seems like a wall of proof, and if it were in defense of greenhouse gases, you would probably have good cause to be mostly convinced. From what I can tell in nutrition, that is probably not the takeaway that you should have, necessarily. You could probably make just as convincing a case against saturated fats or fructose or something. I am partial to a somewhat "zoomed out" approach, I'd love to just see more studies of humans over long periods of time eating vegetable oil in good experimental conditions. As I said, there's a disproportionate lack of them, especially given how prominent they now are in our diet. Those sources were strong for this theory too. Here's one, PDF warning.
https://www.bmj.com/content/353/bmj.i1246.full.pdf+html
Only a handful of randomized controlled trials have ever causally tested the traditional diet-heart hypothesis. The results for two of these trials were not fully reported. Our recovery and 2013 publication of previously unpublished data from the Sydney Diet Heart Study (SDHS, 1966-73) belatedly showed that replacement of saturated fat with vegetable oil rich in linoleic acid significantly increased the risks of death from coronary heart disease and all causes, despite lowering serum cholesterol.14 Our recovery of unpublished documents and raw data from another diet-heart trial, the Minnesota Coronary Experiment, provided us with an opportunity to further evaluate this issue.
I do think I was mistaken to not have included this stuff, I kind of assumed people would read the sources but that probably didn't happen lol
My primary claim was that we already understand the main proximate cause of the obesity pandemic. It has something to do with people maintaining calorie a calorie surplus—the difference between our calorie intake and our energy expenditure.
If I understand your reply correctly, you are essentially saying, "vegetable oils likely cause our bodies to retain extra calories than they otherwise would." A reasonable conjecture, but let me offer another.
Assume that our bodies do not retain more or fewer calories depending on what we eat. Instead, our calorie surplus is measured reasonably well by the number on the nutrition label. Then, naturally, the problem is simply that we're eating too much.
Of course, this theory leaves a lot to be explained, such as why we're eating so much in the first place. However, we also have a simple answer for that: modern processed food generally tastes good, gets people hooked, and causes us to have more frequent and more intense food cravings. As far as Occam is concerned, I don't see why we need much more than this theory.
That's certainly fair enough! I really don't think that I have any qualms with your logic, my reason for posting and exploring this is partially that maintaining a calorie surplus didn't seem to be a very satisfactory answer, analogous in your argument to saying we know the proximate cause of climate change because more energy is coming in than out--and that opinion was shared by a lot of other people here. In particular, the mysteries of the Peery paper were definitely getting some discussion going.
I'd refer you to the comments on this post--I think a lot of others said it better than I why we at least think this merits more discussion.
https://www.lesswrong.com/posts/fD8jXHvLJrEdSLQrE/obesity-epidemic-explained-in-0-9-subway-cookies
Sounds like both of you think: something in modern food is causing our weight set point to go up.
You think it's the taste, he thinks it's some novel chemical.
I say 'weight set point to go up' rather than 'we eat too much', because I think you both agree that after a successful diet, weight goes quickly back up to where it was, rather than slowly like it would do if we just carried on eating too much.
Is this fair?
CICO is properly applied to a system defined by a boundary. The complete equation is:
inputs - outputs = accumulation + depletion (adjust signs as needed)
where these parameters are as compared to the system boundary.
Inputs for a mammal system are food, water, oxygen, and heat. Outputs are heat, sweat, urine, feces and CO2. Accumulation/depletion within the system would include muscle, fat, plasma, bone, organs, and microbial ecosystem.
Energy inputs to the system can go to the primary host body (e.g. fat accumulation) or to the microbes' ecosystem or output in sweat, urine/feces or heat. The microbial ecosystem requires energy and dietary components as it blooms, changes, dies-off, etc.
Most of the posts/commentary I've seen in the rationalist arenas have never mentioned "CICO" system analyses that include intestinal microbial ecosystem or urinary/fecal output. Here are some studies that address those two areas of the system analysis:
doi:10.1093/ajcn/31.7.1149 "Metabolic Effects of Fiber" Human cross-over design comparing fiber intake. Two diets with the same total kcal, protein, fat. Carb difference of about 20gms and in the amount of fiber: lower vs higher. Almost 1000 kcal more calories excreted in feces with the higher fiber diet compared to lower. About 10gms more fat excreted in feces with higher vs lower fiber diet.
DOI: 10.1016/j.tem.2020.06.002 "Role of Energy Excretion in Human Body Weight Regulation"
DOI:10.1097/MCO.0000000000000696 "Dietary fibers reduce obesity-related disorders: mechanisms of action." "Dietary fiber prevents and treats obesity-related disorders. Mechanisms for this protection include decreased absorption of macronutrients and enhanced satiety. Changes in the gut microbiota and short-chain fatty acids are emerging mechanisms to explain why high fiber diets protect against obesity and have a role in obesity treatment."
DOI: 10.1080/10643389.2014.1000761 "The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology" Includes tables of data from, for example, high/low income countries vs fecal mass output, references to diet type vs fecal mass output, factors affecting fecal output.
Example scholar.google search terms "fiber mechanisms obesity"
From the microbial ecosystem factors side of the "CICO" systems analysis:
doi: 10.1073/pnas.0407076101 "The gut microbiota as an environmental factor that regulates fat storage"
doi: 10.1038/nature11552 "Functional interactions between the gut microbiota and host metabolism"
doi: 10.1073/pnas.0808567105 "Effects of the gut microbiota on host adiposity are modulated by the short-chain fatty-acid binding G protein-coupled receptor, GPR41"
doi: 10.1038/nature18846 "Diet-microbiota interactions as moderators of human metabolism"
doi: 10.1038/s41591-020-0801-z "Effects of underfeeding and oral vancomycin on gut microbiome and nutrient absorption in humans" ..."These results indicate that nutrient absorption is sensitive to environmental perturbations and support the translational relevance of preclinical models demonstrating a possible causal role for the gut microbiome in dietary energy harvest."
DOI: 10.1126/science.1241214 "Gut Microbiota from Twins Discordant for Obesity Modulate Metabolism in Mice" ..."These findings reveal transmissible, rapid, and modifiable effects of diet-by-microbiota interactions."
doi: 10.3945/ajcn.110.010132 "Energy-balance studies reveal associations between gut microbes, caloric load, and nutrient absorption in humans" This is an human, inpatient clinical trial. ..."Furthermore, the observed associations between gut microbes and nutrient absorption indicate a possible role of the human gut microbiota in the regulation of the nutrient harvest."
DOI: 10.1113/jphysiol.2009.174136 "The core gut microbiome, energy balance and obesity" Comparison of human mono- and dizygotic obese and lean adult human twins.
doi: 10.1073/pnas.0605374104 "Mechanisms underlying the resistance to diet-induced obesity in germ-free mice" Mice without microbes don't become obese when fed a Western-style, high-fat, sugar-rich diet. Conventional mice do become obese on the same diet.
scholar.google search terms: "microbes mechanisms obesity"
There is a lot more in this area of the system analysis. I'm going to stop here for now.
EDIT: 8/12 added a paragraph with a link to my post with more stats under the regression
Copied and pasted in its entirety from my blog
Time to try my hand at another unsolvable crisis of the modern world. It is my opinion that something doesn’t add up about the increase in obesity and in all metabolic disorders in industrialized countries. There are a bevy of different theories out there, and it was my initial intuition that the problem, like many others plaguing complex systems, was multi-faceted. In addition, if there was an easy solution, epistemic humility would force me to contend with the fact that I’m just a layman in terms of nutrition, and other people should have stumbled upon the solution.
I’ll lay my biases out right now: I didn’t have a particular horse in this race diet-wise (as you can see from my initial reaction to the LessWrong post), but I definitely do want this to be an easy fix. Something along the lines of the prospect of plastics building up in us with no recourse is not a pleasant one to think about for me, I’d much rather we could just substitute an ingredient here or there.
Nevertheless, there is a theory that is so compelling that I would be remiss not to give my take here.
First, it is important to appreciate that there is something really weird (the Peery paper) about obesity in the modern world (PDF warning). The good people of LessWrong also seem to think so. I highly recommend skimming both those articles before you go forward with mine. I very much agree with their assessment of the weirdness of the epidemic. I also think our current explanations are quite lacking.
Where There’s Smoke
I’ll cut to the chase, I think the smoking gun in this whole thing is the addition of vegetable oils to our diet. I go into it a bit in my comment here, but all that info will be the same as this post.
Firstly, I highly recommend reading this series of posts by Jeff Nobbs. He is more responsible for the meat and bones of this post than I am, I’m just relating it to the Peery paper and musing a bit. It lays out an excellent and compelling case for at least looking at vegetable oils as the culprit.
That about sums it up, I was quite convinced initially. From nearly nothing to 20% of our diet! The correlation is very striking, but the causal mechanisms aren’t studied well at all in humans. It’s actually quite weird how few good studies there are of vegetable oil in humans. The ones that are good are further in Nobb’s series, and they seem to be really bad for vegetable oil.
Line by Line
As I find the assessment of the issue and mystery of obesity compelling in the Peery paper, I will use that as a starting point, attempting to rectify the thesis of vegetable oil with their diagnosis of the symptoms of the obesity epidemic. They list the following mysteries of the epidemic:
Changed over the last hundred years
Yep, here’s an article going into its origin in the American diet. Note the potential conflicts of interest. Not a buyer of a conspiracy here, but there are cards on the table.
With a major shift around 1980
For the 1980 thing, I think they focus on that date a little too much, it’s a monotonic increase in both oils and obesity all the way up. Nobbs cites this guideline, 1980 on the dot, that says “Avoid too much fat, Saturated fat, and cholesterol.” As he notes, the public actually did an alright job following all these guidelines. We largely replaced the fats with soybean oil.
Additionally,
-It could be a threshold that got passed around that time—it looks like that’s about when the average man went from just under to just about overweight BMI per the chart in the Peery paper.
-Perhaps a large cohort was hitting a certain age around that time?
-Global trade really starts kicking off, essentially jumping from 10 to 15% of GDP in 1980. The US grows most of its own soybeans, but this could explain why other industrialized countries go up around then as well.
And whatever it is, there is more of it every year
Per Nobbs, it has been exploding. Here’s another source.
It doesn’t affect people living nonindustrialized lives, regardless of diet
Global trade, new invention from USA, ticks this box for me. In particular, the evidence from Cuba and the pacific islands in Peery really points towards the issue being primarily in something that is imported.
But it does affect lab animals, wild animals, and animals living in zoos
This is one of the most interesting points that the Peery paper goes into. If truly wild animals are having the same issues we are, then it would point towards their thesis of an environmental contaminant. However, I looked through their source, and it seems that:
It primarily looks at animals in labs or under the direct supervision of humans. I didn’t read every single source in that paper, but you can see for yourself. The animals look to be eating food made by humans. When they looked at city rats, they got less obese than labrats. This would be consistent with the hypothesis that it is vegetable oil in human foods causing this, if wild rats eat less food made by humans as a proportion of their diet.
I dug through this paper a bit more, called “Canary in the coal mine.” It also cites this paper as evidence of
This was what I was really looking for. Fat cats and raccoons make sense, what about the deer?
But the source says:
I don’t see the evidence here that contaminants in the environment from humans are causing an increase in the weight of animals that don’t eat food made by humans. That paper was all about climate change and deer getting smaller, I’m not even able to figure out why they were really citing it anyways.
Overall, I am not convinced that truly wild animals, eating their own food sources, are being taken for the obesity ride for us. I think all of this evidence is completely consistent with the vegetable oil hypothesis.
It has something to do with palatable human snackfoods, unrelated to nutritional value
The Peery paper says ‘diet’ or ‘nutritional value,’ but it mainly seems like they mean ‘macronutrients’ and sometimes sugar when they say that diet can’t be the answer. Nonetheless, this is still consistent with the vegetable oil hypothesis—go look at the ingredients for doritoes, froot loops, or even store-bought bread.
It differs in its intensity by altitude for some reason
They go into some mechanisms, give it a read if you haven’t. Maybe Colorado is an outlier. It definitely has a lot of young people who like the outdoors and crunchy granola. I don’t know if this should make or break any theory of obesity per se. But it’s certainly interesting. There’s a lot of talk of lipids and oxidization in papers about veggie oils:
Perhaps that’s something—less oxygen, less oxidization, less CVD? I don’t have the expertise—really no clue there. Oxidation does involve the addition of Oxygen to a molecule, and there is about 20% less oxygen at 6000 ft vs sea level. If you look at a map and squint, that’s roughly the proportion that Colorado is less obese than an average US state. Interesting, but I truly have no idea about this. I think you’d be hard-pressed to use this as a linchpin in an argument against vegetable oils. I think they make some really cool arguments pertaining to lithium, definitely check it out, but it just wasn’t quite clicking for me in the way that vegetable oils do.
And it appears to have nothing to do with our diets
I really think it does. That would be the simplest explanation, vegetable oil or otherwise, and the introduction of vegetable oil is the simplest and most obvious change from what I can see. Given the timeline, and the spread of obesity with trade and industrialization, I find myself disagreeing here. Most experts seem to think it’s some combination of diet and exercise and genetics.
It is still adding up
Alright, so I think vegetable oils explain almost if not all the mysteries of the Peery paper. A few more thoughts, citing the Peery paper:
Well, not the fat or sugar contents. I think we have plenty of studies that show low fat vs low carb etc is kinda a wash. At least, no one can decide on it. But surely there’s plenty of vegetable oil in all those cafeteria foods.
Same location, new lifestyle? If they didn’t also move, and there’s no indication they did, then I don’t see why you should say it’s in the water or the air, when a new lifestyle entails a complete diet makeover. I think this is actually one of the strongest points in favor of a dietary reason over environmental contaminants. Note that these oils do all these things to rats.
Diet won’t work—but a diet of only potatoes did. Chris Voigt ate only potatoes and he prepared them in a variety of ways, only one of which involved “a bit of cooking oil.” Whole food diets seem to help a lot. Those get rid of vegetable oils for sure. But so does fasting, so it’s hard to say. Switching from fats to carbs won’t get rid of the vegetable oils that are in near all processed foods though. There is near universal agreement that processed foods are bad, could this be the reason? Processed foods being bad seems weird to me anyways, what if something just gets chopped up?
Oils are in doritos (ingredient 2), in froot loops (!!), presumably in ‘fried pork skins’. As for wedding cake, couldn’t find a good label on the internet, if it’s store bought it’s probably there though. Seriously, there’s vegetable oil in my Whole wheat bread.
Still on the Peery paper, which I really enjoyed reading, I actually doubt it’s chemical contaminants—you’d think China with the factories and air pollution, or the Congo with mines and terrible water would be worse than us. How polluted are New Zealand and Canada—they have quite high obesity. People in the USA are fatter in rural areas, and the USA really cleaned up its air and water in the past 60 years or so. I totally see where they’re coming from with some of their possible explanations, definitely check the Peery paper out. It’s a great read. However, I really think we should render unto Occam what is Occam’s—a group of added industrial oils went from nearly 0% to 20% of our daily calories, and it completely coincides with our issues.
I ran a really quick and dirty regression, with some sources:
Y axis is obesity %
X axis is vegetable oil intake per capita kg/cap
EDIT 8/12: Here's a post about more stats, I felt like it wouldn't be hard to add GDP to the mix, and it doesn't turn out well for our theory here--GDP seems to explain obesity best. Please do check it out if you know anything at all about instrumental variables, I tried that as a hail mary too.
It’s been a long while since I’ve done any stats, so again, stressing the quickness and dirtiness of this regression. In this case, I’m sure vegetable oil is a very, very strong proxy for the general “processedness” of any countries’ food supply. Eyeballing it, I’m sure GDP per capita could explain at least a good portion of this too. Nevertheless, that certainly looks like something. I’d be especially interested in analysis of individual outliers here, is Saudi Arabia because they only count citizens in one data set? Is China using a ton of oil in factories? I sure don’t know.
I certainly think whatever the true cause(s) is/are, it’s probably some addition of the modern world. Just a century ago, diseases of civilization were vanishingly rare. Whatever the solution is, my money is on a solution via negativa as Nassim Taleb would put it. And a food only created 100 years ago certainly isn’t Lindy.
A call for further study
Alright, elephant in the room time: Scott Alexander already did an excellent piece on this.
But I’m gonna nitpick a bit here. Keep in mind, love his work. The first half could be interchanged with my essay here and you’d probably come away better informed than I just made you.
Theory seems to refer to this idea of vegetable oils being bad—a theory with which we have ample evidence to at least suspect is true, as he says. Evidence that he goes into mostly pertains to high saturated fat diets and why they’re not necessarily good. Also note that I’m particularly concerned with Soybean oil as that is the bulk of the increase, and his study discussions don’t involve it.
For the second part I don’t see any reason why we shouldn’t be nearly completely agnostic on high saturated fat diet, from my reading here, my takeaway is to avoid processed foods at the very least, and to especially avoid vegetable oils. I haven’t seen anything to necessarily go in the direction of a saturated fat heavy diet in particular. I don’t see why we don’t have the option of a little olive oil, or just not completely submerging all our food in some kind of fat or oil for 20% of our daily calories. From what I can tell, there’s a fair bit of room in the middle—see the mediterranean diet, which is one of, if not the most universally lauded diets ever studied. Its defining feature is probably the generous use of olive oil and omega 3’s in the meat—two things entirely consistent with our theory here. I don’t see why we should write this off on the intricacies of saturated fats vs PUFAs when the overall body of evidence is scant to begin with—and our primary focus, zoomed out, is in my opinion the question of new vegetable oils, which have other factors inherent to them.
My main point in this entire essay is not that PUFAs are bad per se, it’s that these new vegetable oils are probably bad. I think Scott would agree, we have nearly the same takeaway, but the reason I’m addressing him is because everyone who read that seemed to come away with the impression that this was a dead end. Clearly I disagree with that, I spent all day on this.
Alright, so what did we learn here? Vegetable oil is a new, highly processed addition to our diets in the industrialized world, and stands to potentially explain a lot of the quandaries that continue to baffle us about the crisis of modern health. It’s in damn near everything, we get 20% of our calories from it, up from near 0%, and for some reason, no one seems to mind that and we all just argue about carbs and stuff. People haven’t provably applied this theory to lose weight, but also no one seems to be trying. I don’t see why it shouldn’t be our prime suspect, however we don’t seem to know the causal reason for why this may be from quality human studies, although the Nobbs piece and its associated sources put forth plenty of possibilities to choose from.
I don’t know for sure what the answer is, any implication that I did was simply so I didn’t have to qualify every single statement. I’m largely just trying to get the conversation going, and I’m by no means an expert.
For giggles: conditional on us solving the obesity crisis by finding one primary cause, I’d give the addition of vegetable oils 45% likelihood of being that cause. If we’re in an essentially multi-factor scenario, I think it still has a large role to play, based off of what I’ve seen so far. I definitely would like to know more about the gears of the science here, and I’d like to hear some good rebuttals to this as well, I didn’t find many that I found required addressing in this initial post, but that’s mainly because this is only on the radar of people screaming into the void.
I’d like to express my gratitude to everyone who reads this blog, and to all the sources I cited. Without exception they were fascinating and well written. We’re all in this together, trying to figure out just what in the world is going on here.