A Contamination Theory of the Obesity Epidemic

If we were to hypothesise that some environmental factor is causing a significant fraction of the obesity problem then how would we test it?

The statistical silver bullet you're looking for, assuming you can't run multi-decade RCTs or convince entire countries to dramatically change their water policies (sounds a bit tricky?), is variance components analysis.

You want a variance component analysis equivalent to heritability, but for water/obesity. This is a perfect match: you have a very high-dimensional measurement (GC-MS of drinking water & foodstuffs), whose components you can't observe because you don't even know how many there are much less which ones (like the unknown chemicals that the original contaminants may react into along the way**), where direct prediction/regression would fail because it requires absurd amounts of data (especially given the statistical issues they outline), and where your original research question is not "where is the needle in the haystack" but "does this haystack have any needles at all".

In behavioral genetics, if you plot pairs of people by their genetic similarity and their phenotypic similarity, you will find that people similar on both tend to cluster; and the more heritable the trait is, the more they cluster. You can do this for kinds of similarity which aren't 'genetic'. The idea of variance components is to switch from directly correlating/regressing the specific chemical levels in water, trying to measure the exact direct effect of each chemical on obesity, to instead asking, "how similar, in terms of overall water chemical composition, are similarly far or thin people? Do the chemical spectrums of fat people tend to look similar, and the spectrums of thin people look similar? Do they co-vary, and cluster?"

Think of the water GC-MS as a sort of fingerprint or high-dimensional summary. It doesn't need to contain the actual critical datapoint, just a lot of correlates/proxies thereof (eg you can just shine some light on leaves and it'll work!). The point is not to directly measure the culprit, but to indirectly measure how distant the datapoints are; perhaps chemical A shows up and chemical B does not show up clearly, and B is the real cause, but as long as chemical A correlates with chemical B (maybe it's a different reaction product, or just gets manufactured or used in close correlation with B), then you will see that fatties tend to have close-together water spectra (because of A) and you will have strong evidence that "there is something in the water" because where the bad water clusters the fatties cluster.

So, you'd do something like record the BMI of 10,000 people, take a sample of their drinking water, GC-MS it (ideally, but many other analytical techniques could be used and maybe some would be better here, I'll defer to any actual analytical chemists on that topic), and then plug into a mixed linear-model. You can plug in covariates as necessary (families/pedigrees to jointly model genetic heritability, ZIP codes, age, sex, local mining/factories, already known harmful contaminants the GC-MS detected, that sort of thing). This can be done at multiple levels: individuals nested in households, within regions, within countries, etc. The amount of covariance between the water spectrum and BMI measures the amount of variance the contents of the water en masse can explain, and depending on measurement error and whatnot, given the genetic heritability bounding how much water-heritability can explain, you should get somewhere <30%. Under most theories of obesity, it's difficult to see why one would predict a water-heritability different from 0%*, especially if one has already included altitude/SES/household/region as covariates (which should cover all the obvious confounders like "maybe contaminated water is just a proxy for living in a poor region / having mining nearby / being poor"), so anything >0% is highly suspicious.

This doesn't require any RCTs (or interventions of any kind), longitudinal datasets, n in the millions, or any of the barriers to most of the proposed tests. You only need a cross-section of obesity/water-samples. Individual level is ideal, but doing it with geographic units can be useful too if that is what is available across enough units (individual n are much nosier than k, but also much easier to get high statistical power with). This may even already exist! Drinking water is often tested for many reasons, and obesity health data is standard medical data collected in almost any relevant research; so there ought to be a lot of possible cross-references.

* you could do this with food as well but I focus on water because water is a lot more consistent day to day, and food results would be ambiguous. A single day's food is still not very representative of individual consumption (maybe your wife cooks healthy at home but then you eat processed garbage at the office, and the sample comes from the weekend), so it provides a very poor measurement of the overall diet's chemical signature. And if you demonstrated a large food-heritability of obesity, this would just be taken as proving that "see? sugar / fat / calories / highly-palatable processing causes everything, just like we said all along!", and be weak evidence for contamination at best.

** They also raise the problem of interactions & nonlinear responses. These are issues in behavioral genetics too, of course, with dominance/epistasis particularly, and can be dealt with similarly in the water context: "narrowsense" vs "broadsense" heritability covers simple additive vs interactions, and you can do things like DeFries-Fulker, I think, for nonlinear responses. My guess is that contamination would be 'additive' mostly, for similar underlying reasons as genetics tends to be 'additive': many interactions are just constants because they are done on a fixed background of chemistry, and promiscuous interactions average out to additive effects. But this is the sort of thing to worry about only after having done the straightforward work.

Have you ever seen or even heard of a person who is obese who doesn't eat hyperpalatable foods? (That is, they only eat naturally tasting, unprocessed, "healthy" foods).

This seems like the occam's razor expanation to me. Some of our new flavour/texture combinations are so rewarding that they easily overcome the natural stop signals, leading to excess caloric consumption in most (to a variable degree), which leads to weight gain in some.

A study which gave its participants a 1000cal/day dietary surplus found while some participants gained 14kg of fat over the course of the study (I think it was for 3 months), others gained as little as 4kg. As one would expect, there is genetic variance in one's vulnerability to the effects of a harmful caloric surplus, and there is probably also genetic variance in one's susceptability to hyperpalatable foods. 

Oh, huh -- looks like this paper is the summary of the blog series that "Slime Mold Time Mold" has been written about it? Guess I can read this paper to skip to the end, since not all of it is posted yet. :P

The altitude correlation would seem to suggest drinking water in particular as a culprit, and suggests a simple and straightforward study that would settle the question once and for all: randomize a group of households to either receive reverse osmosis filters on their taps, or not, then track whether the people in those households become obese.

I checked whether this study has been performed, and as far as I can tell, it hasn't. There have been studies that randomly installed reverse osmosis filters, but they were checking for something else and didn't track peoples' weight.

↑ comment by gbear605 · 2021-07-25T04:01:11.401Z · LW(p) · GW(p)

Another effect of altitude is the atmosphere, and there is evidence that the active ingredient in altitude decreasing weight is the thin atmosphere. For example, "One study on rats found that they ate 58% less one day after being transported to Pike’s Peak, and were still eating 16% less per day two weeks afterwards." The immediate effect strongly suggests that it's not caused by anything in the water source.

Replies from: Bob Baker

↑ comment by Bob Baker · 2021-07-25T04:13:07.622Z · LW(p) · GW(p)

See page six of the paper for the authors dealing with this point. It's certainly a potential explanation, but the map of obesity in the US does seem to suggest that being, say, at the mouth of the Mississippi basin is much worse than being on the west coast, despite them both being at sea level.

Replies from: Natália Mendonça

↑ comment by Natália (Natália Mendonça) · 2022-05-06T14:25:36.194Z · LW(p) · GW(p)

The mouth of the Mississippi basin is much poorer than the West Coast, and has a lot fewer Asians (who are exceptionally thin). I'd guess those things probably play a role. 

Replies from: Natália Mendonça, Natália Mendonça

↑ comment by Natália (Natália Mendonça) · 2022-07-22T17:24:11.307Z · LW(p) · GW(p)

Educational attainment is strongly correlated with obesity rate across US states: 

I used this obesity dataset from the CDC and this educational attainment dataset from the USDA.

↑ comment by Natália (Natália Mendonça) · 2022-05-09T01:38:00.971Z · LW(p) · GW(p)

Also, the mouth of the Mississippi basin does seem to be at a lower elevation than the West Coast:

Replies from: thomas-kwa

↑ comment by Thomas Kwa (thomas-kwa) · 2022-05-09T01:50:47.526Z · LW(p) · GW(p)

That's a map of highest elevation by county. I don't think most people in LA County (third from bottom on the California coast) live above 6800 feet, because most people don't live on mountains even if one exists in their county.

Replies from: Natália Mendonça

↑ comment by Natália (Natália Mendonça) · 2022-05-09T02:25:14.373Z · LW(p) · GW(p)

Oops, sorry. 

The map of average elevation by county looks similar, but you are right that this matters very little because people are disproportionally likely to live in low elevations. 

Heads up: the given link to the paper seems to be broken, because it links to a 4 page paper called "The Beginning of Time" which is entirely unrelated to nutrition and your post.

Note that Korea and Japan have very low obesity rates (around 2-3%), despite being highly developed and having widespread availability of hyper-palatable food. Definitely worth to check whether some chemicals are more present literally everywhere else  than in those two countries. 

Contra the obvious genetic hypothesis,  genetically similar China and Taiwan have very high rates of obesity.  I don't know whether Koreans and Japanese might be genetically closer to each other than to Han Chinese. 

Given the Confucian influence on the culture of Korea and Japan, maybe it is peer pressure that keeps people from becoming overweight? Plausible, so it might be worth to look into the case of hikkikomoris, which is the Japanese phenomenon of  refusing to leave your room/apartment  for months or years while being supported (usually) by your parents. As such, they are likely not actively managing their weight. They are obviously a hard group to survey, but these studies looked into characteristics of hikkikomori and neither mentioned overweight,  so that is a point for cultural or genetic reasons.

However, your linked paper says that Japanese that move to America do tend to gain weight, so it cannot all just be genetics. 

I wonder whether Asian kids adopted by non-Asian parents are more often overweight than kids raised by Asian parents.

EDIT: My complete thoughts are here: https://goodtosell.substack.com/p/a-response-to-a-contamination-theory

https://www.jeffnobbs.com/posts/what-causes-chronic-disease

I’ll add more and fix this up tomorrow at my pc. Sorry bout the sloppiness and the formatting, you’ll see why I was so excited. I really can’t stress just how much this adds up. It’s really quite uncanny. I encourage anyone to just read that instead of me, but I gave this a shot for when you’re done with that.

Just found this, it reminded me of your post, as I’d been thinking about it a ton.

Looks to me like it’s vegetable oils. Practically fits everything perfectly. The new addition to our diet. They were only invented about a hundred years ago. They’re in nearly everything packaged in the supermarket—hence why it looks environmental, why the rats got fat, why the processed food looks bad, even why the Cubans got skinnier, since these oils are highly implicated in global trade.

If you look at what soybean oil does in mice studies it’s kind of ridiculous. Not a medical professional, so who knows. Especially how it solves most of the points addressed in that paper.

1. Changed over the last hundred years

Yep

2. With a major shift around 1980

For the 1980 thing, I think the author focuses on that date a little too much anyways, it’s a monotonic increase in both oils and obesity all the way up.

-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

-Perhaps a large cohort was hitting a certain age around that time

-Global trade really starts kicking off

3. And whatever it is, there is more of it every year

Yep. See source.

4. It doesn’t affect people living nonindustrialized lives, regardless of diet

Global trade, new invention from USA, ticks this box for me.

5. But it does affect lab animals, wild animals, and animals living in zoos

Lab animals fed store bought food, yep. Wild animals, no source from what I can tell, surely raccoons are eating plenty of cheetos nowadays.

6. It has something to do with palatable human snackfoods, unrelated to nutritional value

Yep. Unrelated to carb or fat content.

7. It differs in its intensity by altitude for some reason

Also think they’re a bit too focused on this one, maybe there’s a mechanism, maybe Colorado is an outlier. 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. Maybe it’s something else for that.

8. And it appears to have nothing to do with our diets Not so sure about that one

Some quotes and my rebuttals:

But again, it’s not just the contents. For some reason, eating more fat or sugar by itself isn’t as fattening as the cafeteria diet

Well, not the macronutrient contents. I think we have plenty of studies that show low fat vs low carb etc is kinda a wash. But surely there’s plenty of vegetable oil in all those processed foods.

For an abrupt shift, 1980 is when the USA started guidance going against saturated fats….and we replaced lard and butter with veggie (soybean) oil.

When humans switch from an ancient to a Western lifestyle,” he says, “they experience increased waistlines, reduced insulin sensitivity, higher blood pressure and a host of related disorders and diseases.“

Same location, new lifestyle? If they didn’t also move, I don’t see why you should say it’s in the water, vs a complete diet makeover. Note that these oils do all these things to rats. The oils also seem to act on their brains, messing with the hypothalamus which from what I could tell seems somewhat implicated in set point type stuff.

Diet won’t work—only potatoes did. Whole foods does. Those get rid of veggie oils for sure. Switching from fats to carbs won’t get rid of the veggy oils that are in near all processed foods though.

“palatable supermarket food”; not only Froot Loops, but foods like Doritos, pork rinds, and wedding cake.

Oils are in doritos (ingredient 2), in froot loops even, 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.

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. The USA really cleaned up its air in the past 60 years or so, no dice on that in my book.

Finally, I don’t have a horse in this race, i posted some thoughts a few weeks ago here too with an entirely different explanation. I don’t usually get emotional about science, and try to kill my bias. But something smells here. This works way too well, it’s new, it’s simple, why is this not one of the first things anyone thinks of? The people who wrote the paper in the OP didn’t address this at all, when veggie oils are in nearly everything and absolutely exploded from nothing about a hundred years ago. I’ve done a fair bit more digging, there are allegations of corruption—especially of Proctor and Gamble (crisco) buying out the American Heart Association essentially. I’m skeptical, but it does seem like they were throwing some money around in support of Crisco.

Per the source:

Throughout our decades-long battle with chronic disease, Americans have closely followed everything the CDC, AHA, and USDA have told us to do. We're smoking less, drinking less, exercising more, eating less saturated fat and sodium, and eating more fruits and vegetables. Still, chronic disease and obesity rates continue to rise. All the while, vegetable oil has steadily and stealthily made its way into our pantries, restaurants, and packaged foods, now contributing 699 calories per day to our diets, or about 20% of everything we eat.

Tldr, vegetable oils were invented about 100 years ago, highly promoted around when they started to turn on saturated fats, and line up with close to every mystery the authors assert. It’s also a way simpler explanation.

1. Diets produce modest reductions in weight over the span of weeks or months, but the weight comes back over time. There's been a lot of searching for effective diets, but they're all about the same in large populations.

I think this problem is extremely real but the academic studies overstate them, because people who succeed with their first diet and keep succeeding don't sign up for diet RCTs. They're selecting diet-resistant people.

Adderall (and other similar stimulants) are known to suppress appetites. They're not a great choice to prescribe as an appetite suppressant, due to their major other effects and since it doesn't seem to affect everyone, but they do work.

No doubt environmental factors should be considered. Assuming for a moment it’s plastics in the water, say, I’m curious what mechanisms would explain why we don’t see really obvious trends by geographic area (independent of other factors). For example, it’s of course not all environmental because people in the same neighborhood/family have different outcomes.

To throw my hat in the ring: all things metabolic seem highly intertwined. I faced an interesting trillemma once upon a time—I had high blood sugar, high cholesterol, and low testosterone(alcoholism). I initially cut calories: that was tough because my testosterone declined even more, and burning fat also “releases” (not a technical term) cholesterol from the fat back to the bloodstream. But I improved blood sugar. After that miserable time, I messed around with a lot of different things, but ultimately settled on a general healthy whole-foods based diet, lifting weights, and hiit. Worked like a charm. What was interesting to me was how everything failed at once, and in roughly the same proportion: my cholesterol and blood sugar were just hitting the danger zone, and my testosterone was just about hypogonadal. Interesting, because you would think one acute stressor would affect, say, only blood sugar. But that’s not the case, it seemed as if the system was highly interconnected, and “slack” could be taken from one parameter to improve another. Along the same line, it seemed as if the whole system could be tightened up all at once as well, by a holistic approach. But focusing on blood sugar came to the detriment of cholesterol and testosterone. So one bad input could turn all the outputs, even the non-direct relationships, bad all at once. But the opposite was not true.

Another thing, anecdotally I’ve observed that generally people either stay at a good weight, or pretty much always decline monotonically, once they hit some sort of inflection, i.e. insulin resistance, past a threshold. Rarely do you see that their tendency goes from effortlessly maintaining 150lbs>effortlessly maintaining 155lbs. It seems more that they effortlessly maintain 150lbs, then something breaks, and they add weight until they are old enough to have even bigger problems. This may be why the acceleration at once, perhaps the average level of some cumulative damage /other measure went from just under to just over said threshold around 1980.

What am I saying? It’s probably fundamentally super complicated. I almost don’t even think we’re lacking in data or really in understanding of the basics—it seems we need a statistical revolution to really get to the bottom of this. My intuition tells me that the answer is there, it’s just not going to be a simple linear correlation. Same goes for most complex systems too, by the way. Or, equally likely, God just starts fucking with us when we try to figure out things that he simply wills, so he fudges the data

Perhaps it is carbon dioxide. Here is a paper on it:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3341709/

To summarize, the idea is that high partial pressure of CO2 causes blood pH to change, which influences the body's regulatory mechanisms and eventually leads to obesity.

At higher altitudes the carbon dioxide fraction in the air is unchanged, but the partial pressure is lower. I'd expect that lower partial pressures of CO2 would mean less effect on blood pH.

My layman's understanding (and personal experience based on self-experimentation over the past decade trying to get to a healthy weight range) has been that this is a threshold problem. For generations we've been gradually making intentional and unintentional changes to diet, activity, and environment that make it a little harder for our bodies to regulate weight, until eventually we use up the slack and start actually gaining.

I think this is important, because if true, it means that there will never be a silver bullet, nor a single solution at either an individual or societal level. It also means the solutions don't have to look like the proximal cause that "pushed us over the edge" if it's easier to reverse changes that happened much earlier, or if we need to do other things to overcome sources of hysteresis in our bodies' weight-regulation systems. We have a lot of possible levers: Reducing pollution, eliminating exposure to certain chemicals, curing some infections, altering diet composition and methods of food preparation, altering timing and number of meals, altering speed and social context of eating, reducing various forms of stress, varying all the different dimensions of type and duration of exercise, changing how we sleep, changing indoor lighting and air quality, changing time spent outdoors, improving hydration, reducing chronic inflammation, and that's just what I thought of in two minutes. It is hard to do plan and stick to enough self-experimentation over a long enough time to find out what actually works for an individual, even for very smart and educated people.

I've called this the "phlogiston" theory of obesity - something systemic and undetected is at work.

It's not necessarily wrong, there's certainly some evidence that the same behavior 100 years ago would have had different results. On the other hand, the general alleviation of poverty and famines, as well as the presence of "hyper-processed" foods like Oreos are certainly part of the reason and are largely ignored.

If I had to guess what the "phlogiston" is, I would guess CO2 concentration. I don't have any evidence whatsoever, but it's a politically-convenient theory and the timing mostly works.

For a while I had a theory that "sugar in a beverage not paired with bulky food" added calories without the human brain/whatever noticing and having the satiety mechanism(s?) kick in when the right calorie consumption level was hit. The archetypal study here would involve carefully measuring how many calories like this, C, that a person consumed per week, and then C/3500 is how many pounds per week they should gain over time. 

I dunno if this is true, but it seemed close enough to likely to be true that I started rejiggering my habits and feelings about food to try to get my personal C "close to zero when left to my own habits and choices". If I'm just going to "drink" now, I try to basically only drink water or milk.  Not ALWAYS. Sometimes I find myself craving orange juice, but I try to eat other similar fruits first, before I fall back to a cup of delicious delicious citric acid flavored sugar water.

In this section there's a hunter-gatherer tribe for everything. I'm a little suspicious of this line of evidence because these small human populations could plausibly have evolved to tolerate their specific environment but, if you want a group of humans with zero-percent obesity who eat 60%+ carbs, or 60%+ fat, this paper has one for you. They have plenty of food, they just live happily and remain thin.

Is there a tribe that drinks a LOT of fruit juice?

The big obvious macrocausal elephant in the room is corn, and how corn is in everything, and how cows are fattened on it (so milk and burgers are actually corn), and then there's HFCS, and corn oil, and so on. Cheap edible calories, as far as the eyes can see. 

(You might link the "fruit" juice theory with the corn theory, because a lot of juice is just sugar water with fruit flavorants and a lot of sugar is corn based. If you're not careful, an attempt to drink apple juice will lead you to actually drink "corn" juice.)

If we follow the corn calories, I could imagine them cascading out, through pets, and lab animals, and into the garbage, and into mice and possums (and anything that eats mice and possums)... but NOT into deer nor any other non-garbage-eating herbivores.

4. It's not just humans: lab animals and wild animals appear to be getting fatter over time too. (A surprise to me, but casual inspection seems to confirm that this is really a thing that reviewed papers are noting.)

The wild animals seems surprising to me. I feel like I can probably suggest animals where it is NOT happening... like: I bet it is not happening in polar bears. How detailed was the analysis here? This seems like the place to find some "surprises" that constrain the causality more precisely.

After reading the whole thing I don't think he disposed of the hyperpalatability hypothesis. That was the weakest part of the series. 

One other thing that was missing related to sugars and seed oils. I have not been able to find any 'native' poulation with access to large quantities of both. You do have some with access to large amounts of fruit or honey, as mentioned. And also some (Kalahari desert dwellers eat large amounts of Omega 6 rich mongongo nuts "why farm when the world has mongongo nuts") with access to large quantities of Omega 6 oils, one alleged culprit in seed oils. But I don't see any that have both, Processed foods are rich in both and this is novel.

Still it is worth reading IMHO and I find myself somewhat convinced that Li has a role.

My larger-bodied theory is that the "work-week" & all of its over-regulated time tables, don't properly co-relate to most people's biological needs. "Rushed" anything is seen as negative, I've never felt good a single minute when the word "rush" was in my head. With a work-week regulation of everything is the expectation, fall off the horse & your troubles become worse. Your peer evaluation goes down, the work will not be offloaded or considered too much for one person, it is compounded, or you must act like an "ubermensch" for as long as it takes to get caught up. Remembering that you fell off the horse precisely because of the weight you carried without these extra burdens, you must now "rush". I thinked the mental directive, "rush", triggers over-feeding because of it's base narrative of "need", which has overlap with survival instincts. This is the pyschological feed that turns the modern worker into a slave. Constant retriggering of the "need" directive, makes of man a mule & a yoke.

I also posit that overall population feeling is transferrable, at least for high-contact groups. Which is most to all people. Telepathy or not, I can feel the anxiety of someone through all of their cues & I pay the cost of giving my "attention" to their "direction" by inheriting a distinct percentage of their feeling, depending on my attention input weight. When people feel aggressive, their peers feel aggressed by inheriting a bit of the aggression. This is a telephone game, where average response to high stimulation by those whose "need" directives are perpetually retriggering decides the overall feeling state of those with professions that require high-contact & high #'s of people met per day.

Persistence wears down resistance, 
eventually the body's natural weight regulation "capacitors" break, or at least conform to the new norm, hence the semi-permanence of weight gain after the initial deflowering of the non-obese individual.

This secondary theory could use a lot of work, & costs a decent amount of energy for me to add clarity to, but I believe in everything I've written

One possibility not mentioned is the removal of an environmental contaminant:  1980 corresponds to phase-out of leaded gasoline.  Could it be that lead was making us (and all the animals) both dumber and skinnier?  

It's a long shot, but how about oxygen deficiency? Our cells' mitochondria use oxygen to produce ATP by 'burning' glucose. Could less oxygen mean less energy consumption and therefore more fat storage? All I could find about the evolution of oxygen concentration is on https://en.wikipedia.org/wiki/Oxygen#Later_history: Oxygen levels in the atmosphere are trending slightly downward globally, possibly because of fossil-fuel burning.

We'd expect altitude to be positively correlated with obesity, though.

There are studies, and studies of studies, showing that exposure to various PFAS chemicals are positively correlated with weight gain. I really think PFAS is the culprit. The extent that many municipal water systems are contaminated with PFAS has only recently been coming to light. People have been taking in a lot more PFAS contamination than they realize.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723340/

I'm currently living the "clinical & pristine" diet outcome that you have theorized would be worth studying. I drink only distilled water w/ a small amount of added electrolytles, & eat only foods that came out of the Soylent meal replacement boom(that also scored the highest on my [enjoyment, body-feeling, satiety, satisfaction, company ethics] matrix compared to their competitors.) eaten only at room temperature or above(I have a strong belief, from approximation by body reactions & a few co-opters in the form of Gwern & a few studies, that cold foods are not digested properly & may slow metabolism, thus creating whatever behavioral/biological domino effect that would have. Sub-optimal.).

I collapsed into this diet outcome after a ferocious bout with a feeling-set [depression, low-motivation, erratic eating habits, inability to formulate coherent strategies] that I recognized as externally motivated. I changed a few other things, but this was one of the outcomes that my BNN's gradient descent collapsed towards, I had never heard of microplastics or flouride being a nuerotoxin, which has led me to believe in the "mathematicians are often wrong about the details, right about the answer" form of epistemy. I think "something's in the water". It's a shame I'm not closer to the problem, but a few years ago I thought it was the gutter-or-the-grave, so baby steps I suppose.

If use is ever found for someone with my diet composition, I'd be more than willing to pony-up my bio-metric data. I have a strong suspicion that diet composition is well related. 

I'd wonder about the effect of atmospheric pollutants. Altitude would clearly also have an effect if obesity was being caused by pollutants in the air.