12 ms·

A Contamination Theory of the Obesity Epidemic

89 points by jasonhansel 5y ago

alejohausner 5y ago
I was looking forward to this. It's the conclusion to a discussion posted here earlier [1]. 1. https://news.ycombinator.com/item?id=27796557 https://news.ycombinator.com/item?id=27796557
retrac 5y ago
Edit: The following is mostly a non sequitur. My response was based in part on a misreading of the article's arguments. They're concerned primarily with the "consolidation" of obesity since about 1980 without any obvious changes for why. The changes for why were in the previous decades and the chickens should have come home to roost by 1980. Yet we are indeed much more obese than in 1980 but not more sedentary. So... why? This I have to say, is in fact somewhat mysterious. I have a contention with the "obesity hasn't been reversed in any population" claim. Here in Canada, child obesity has in fact decreased in recent years, after several decades of continual increases. Given that childhood obesity, and obesity in general, has been a major social issue everyone is aware of and has been working hard on (I assume), the small decrease in proportion to the amount of energy invested, is rather depressing. Still, maybe cause for some hope. > Something seems to have changed. But surprisingly, we don’t seem to have any idea what that thing was. We don't? While exactly how much this is a factor is contended, I thought it was near-consensus at this point that it's because we are less physically active. The timeline certainly fits - beginning about 1890 and ending about 1975 -- that is the period from the beginning to universal adoption of the car. Between home appliances, powered vehicles and industrial automation, many modern people don't actually have to do anything physical. Hauling their corporeal form between various chairs is literally all the exercise many people get. This would be unfathomable to my great-grandparents. They walked to the store then hauled the groceries home. They walked a few miles every Sunday to go to church. They walked to work. They tended the fields largely with manual labour and a horse. They mowed the garden and yard, by hand. Every nail in the home, driven by hand. Ground meat for dinner? Minced by hand. And by then, industrialization had already completely changed things for them, to their own grandparents, giving them what they must have thought an amazing amount of free time and leisure. (My great-grandparents clothes were almost certainly machine-woven, for example.) If we're eating as many calories, or slightly more, as our grandparents did, while barely moving in comparison to them, is it any surprise we all got really fat? In fairness to the paper, I suppose one could view this social change as a mimetic contagion of a sort.
- chillpenguin 5y ago
  I'm pretty sure we are eating more calories than our grandparents did, too. Portion sizes for common things are much larger now. You can look at muffin sizes for example and how the average muffin is physically larger today. Same with burgers, soft-drink cup sizes, etc. But yeah I agree with everything you said as well regarding lack of physical exercise.
  - krona 5y ago
    > I'm pretty sure we are eating more calories than our grandparents did, too It varies from country to country. In the UK for instance, calories per household decreased 15-30% from 1980 to 2009 (https://ifs.org.uk/bns/bn142.pdf https://ifs.org.uk/bns/bn142.pdf). The trend has continued since.
- yeuxardents 5y ago
  Certainly the addition of ubiquitous sugary snacks and drinks everywhere as well contributes, how is that discounted so easily. So much processed food within a 2 minute car rides reach, and it only require 30 paces into and out of the store for 2000kcals in treats!
- nickthemagicman 5y ago
  This is certainly true from an personal anecdotal perspective. The minute I went from college where I was very active to an office job the pounds piled on. What's interesting is that if you're poor modern Capitalism doesn't allow much free time to exercise, which might explain why the obesity epidemic effects the poor more.
- zosima 5y ago
  The mystery is not the modest increase of obesity from 1890 to 1975. This increase is very likely caused by reduced activity and increased caloric consumption. It is the dramatic increase in obesity from around 1980 and onward that is a mystery. And part of the mystery is that animals living around humans, in the wild or in the lab, seems to have gone through a similar increase in body weight. The article goes through why this dramatic increase can not just be due to reduced exercise or increased caloric consumption, but must have some other, unknown factors, to explain it.
trhway 5y ago
>So what changed in 1980? Effects of the agriculture policies starting 1973 which resulted in HFCS everywhere? Including sugar replacement with HFCS due to tariffs https://scholarworks.montana.edu/xmlui/bitstream/handle/1/2554/WiltgenT1207.pdf https://scholarworks.montana.edu/xmlui/bitstream/handle/1/25... "On the demand side, high fructose corn syrup (HFCS) was beginning to make inroads as food and beverage manufacturers sought to replace sugar with a less expensive input. As prices dropped, the International Trade Commission opened hearings to determine whether or not imports were the source of “serious injury or threat thereof” (USDA, December 1976, 15) to the domestic industry and, in March 1977, recommended that imports be restricted. President Ford, anticipating this recommendation, increased the tariff on raw sugar from 0.625 cents to 1.875 cents per pound in September 1976. When the 1977 Food and Agriculture Act took effect on November 8, 1977, a price support/ loan rate program was established (see “Price Support Loan” section). To reduce government expenditures on this new program, President Carter raised import fees to 2.7 cents per pound for raw sugar and 3.22 cents for refined sugar. The import fee, coupled with the import duty, served to control imports in the late 1970s. Both the fee and duty reached their peaks in early 1979, when the fee for raw sugar was 3.22 cents and the import duty was 2.8125 cents per pound. "
- PaulHoule 5y ago
  Or glyphosate and/or neonicotinoids.
- smegcicle 5y ago
  preservatives prevent the natural breakdown of food, so it doesn't seem surprising that they could have a negative effect on digestion
getpost 5y ago
My money (and my dietary choices) are on excess PUFA as a key contributor to obesity. https://www.youtube.com/watch?v=pHnPinYI2Yc https://www.youtube.com/watch?v=pHnPinYI2Yc https://fireinabottle.net/torpor-sloth-and-gluttony-scd1-causes-humans-to-store-fat/ https://fireinabottle.net/torpor-sloth-and-gluttony-scd1-cau...
- alejohausner 5y ago
  Polyunsaturated fats are known to suppress thyroid function, this leading to lowered metabolism and weight gain. A quick search brought up this: ANTI-THROID EFFECTS OF PUFAS (POLYUNSATURATED FATS) AND HERBS January 2012 Trakya University Journal of Natural Sciences 13(2) Authors: Başar Altınterim Malatya Turgut Özal University
- jnwatson 5y ago
  This is consistent with the elbow of the increase in obesity being about 1980. Canola oil was invented in the 1970's and really hit its stride in the US in the 1980's.
- nikolay 5y ago
  According to Ray Peat, any amount of PUFA is toxic, but especially so in quantities of more than a gram a day. And most of us today get tons more than 1g. One of the reasons is the desaturation of cardiolipin in mitochondria, leading to instability and dysfunction.
DiabloD3 5y ago
I prefer the other theory I've heard: the body's gauge on starvation is not based on caloric intake, but based on nutritional intake; ergo, low nutrition diets that have sufficient calories (such as the Standard American Diet) make the body think winter is coming soon, and time to get extra plump. This is mainly the basis of my dieting. I reached a peak of 340, and in exactly a year, while maintaining the same CICO, but changing from the SAD to strict non-Keto Paleo, became 214, and then eventually slimmed down to the 175-185 range. I now eat mainly focused on nutritional density, and keeping the weight off is easy.
- nickff 5y ago
  CICO meaning calories-in-calories-out? Please avoid undefined and uncommon acronyms. Did you do food diaries/journals as you increased weight, and as you lost weight? I have lost significant amounts of weight by reducing caloric intake, and noticed that my records on the way up and down were very different.
  - thefourthchime 5y ago
    I believe so. It sounds like he doing paleo without keto. I may be wrong, but basically just eat food on the perimeter of the super market. Veggies, meat, dairy. Nothing processed.
  - temp_praneshp 5y ago
    In this context, it's a common acronym. Maybe you are just not as well read in this area as in others? Googling CICO on an incognito window are 100% hits for calories-in-calories-out.
    - nickff 5y ago
      That's how I figured it out, but I consider 'this context' to be Hacker News, where 'API' is common, but 'CICO' is not.
      - imwillofficial 5y ago
xxxtentachyon 5y ago
This might have been covered in some part I skimmed over, but they never seemed to offer a mechanism for contaminated water in a drainage basin entering the local food supply via processed foods in a way that wouldn’t also impact a plant-based (e.g. potato-only) diet. Did anyone get any insight there or is that really a gap in their explanation? As an aside, I have an unfortunate and deep association between Microsoft Word-typesetting and graphs with papers I wrote in high school that put me in a skeptical stance from the start
- joe_the_user 5y ago
  The thing about the article is it's not really offering any air tight explanations. It looks at a significant amount of data and asks what's correlated and what isn't - many common explanations simply don't fit the data at all. So it comes down to contaminants and psychological effects. But it is not making any definitive pronouncements about which contaminants or how.
- jeffbee 5y ago
  What makes you suspect this was typeset in Word?
- jaggederest 5y ago
  You have to segment the claims in two: Claim one (We have eliminated mechanisms aside from contamination for the obesity epidemic) rests essentially on anthropological studies with "uncontaminated" populations and conversely on the fact that animals in close contact with humans are also becoming obese rapidly even when holding calories constant (e.g. lab rats) Claim two posits some substances that might be responsible, and I think roughly is oriented around: a) antibiotics are intensively used in animal cultivation in a way that might leak into the food supply and water table downstream. b) PFAS accumulate biologically after exposure at parts-per-billion levels, and become increasingly more concentrated as you go up the food chain and downstream, but e.g. potatoes are not exposed to enough PFAS to hit the thresholds for deleterious effects. c) I don't think that lithium is actively taken up by plants to the degree that would affect pure unprocessed plant consumption, it's mostly about direct exposure and water contamination downstream. I think the claim one hypothesis is really strong. I've had a similar hypothesis for a few years now, though mine was more oriented around infection than contagion, but similar in terms of structure - the more people you put close together the more likely they are to cross-contaminate with some substance that makes them obese, and the clearer difference we have between baseline humanity ~100y ago and modern ones suffering from the obesity epidemic. I think the claim two hypothesis is a little bit weaker, but it's interesting that they have 3 proposed mechanisms that range from known effect, known presence (antibiotics), known presence but unknown effect (PFAS), and unknown presence but known effect (lithium), so I think they roughly descend in order of likelihood of explaining the obesity epidemic. I would guess, obviously, the answer is "all three", based just on the severity of the epidemic, but I'd guess it's quite likely antibiotics have a small effect, and also somewhat likely PFAS have a large effect, while I think the lithium hypothesis is the weakest of the three, but would be interesting to analyze further.
Gatsky 5y ago
From meticulously monitoring macronutrients and body composition over periods of 3 months, I find I can eat say 3/4rs of my calculated energy requirements and still get slowly fatter over time. This slow fattening effect is associated with poor sleep, occasional massive calorie bombs due to social events and, for me at least, eating a lot of starches often in snack foods. The sleep is particularly important, when deprived I develop incessant cravings for low quality food. If I sleep well and restrict carbs, I can lose 5kg+ without trying despite no exercise.
- axiosgunnar 5y ago
  It‘s a good point. Sleep more :-)
ellyagg 5y ago
What kind of proof would it take for people to agree that the obesity epidemic is due to food being dramatically cheaper and more palatable than in our environment of evolutionary adaptedness?
- brianberns 5y ago
  Did you read the linked paper? They consider this possibility and reject it.
  - ellyagg 5y ago
    Sure. Did you realize that epistemically they don't have the power to reject explanations? It would certainly be news to Stephan Guyenet if they did have in this case.
- imtringued 5y ago
  Distance to cheap food stores vs organic stores.
- kixiQu 5y ago
  How would that explain lab animals gaining weight?
  - ellyagg 5y ago
    The most likely explanation for this is some combination of 1) lab animals being fed more over time because researchers themsevles have been normalized to bigger food portions, 2) incomparable data of lab animals feeding over time, and 3) fraud because of the pressure to show unusual results.
    - kixiQu 5y ago
      The theory calories-in-calories-out doesn't explain why animals fed controlled diets over time could exhibit a change in weight, pretty much by definition. So instead of trying to extend that paradigm in some way that would explain it -- or even to acknowledge that there could be some auxiliary cause for this phenomenon while saying it's irrelevant to the trends in human obesity, which I think would be a fair argument -- you're saying 1) they aren't actually being fed the same thing, 2) they aren't actually being fed the same thing, 3) they aren't actually being fed the same thing or they aren't actually gaining weight. This is only "most likely" if you begin by assuming the truth of what's to be proved, i.e., begging the question.
zelienople 5y ago
Nonsense. Utter rubbish. People are fat because they eat more calories than they burn. The only reason that studies do not reflect this is that they rely largely upon self-reporting and people lie.
- 542458 5y ago
  That’s not quite true. Your body can decide to do different things with the calories it gets, including storing them. There appear to be a number of things that influence if and how calories are stored, including the source/type of the calories in question. There’s also evidence that gut micro biome affects our ability to absorb calories and what happens to those calories once absorbed. Furthermore, there’s a large question as to why people eat so many calories. After all, we don’t typically see people drink water until they die. What biological process makes food different, that people are willing to overeat? Saying “people are fat because they eat too many calories” is like saying “that building collapsed because of gravity” - true, but not particularly useful when trying to get to the root of things. https://www.scientificamerican.com/article/how-lab-rats-are-changing-our-view-of-obesity/ https://www.scientificamerican.com/article/how-lab-rats-are-...
  - thebooktocome 5y ago
    I agree with you, but I think it's too charitable to assume that the goal in this societal conversation is "Getting to the root cause of obesity". Many people would rather ignore any evidence contrary to absolute, individual culpability and commence with the victim-blaming.
- bluedays 5y ago
  So like… you got some sorts credentials?
- deleted 5y ago
  [deleted]
- joe_the_user 5y ago
  The article cites the results of a number of studies in which people were direct observed.
kelvin0 5y ago
During the 1970s High Fructose corn syrup seems to have kicked off the issue. Low fat was the rage then, and companies needed something to add 'taste' to their various process foods. https://en.wikipedia.org/wiki/High-fructose_corn_syrup https://en.wikipedia.org/wiki/High-fructose_corn_syrup
maxk42 5y ago
Surprised nobody in this thread has brought up the link between obesity and increase in dietary sugar intake. [1] More and more research seems to show that replacing dietary fats with sugars is closely correlated to obesity levels. Most notably, fructose seems to be difficult for the body to metabolize since it has no impact on feelings of satiety. [2] [1] https://farm1.staticflickr.com/861/42814282105_85032f638b_b.jpg https://farm1.staticflickr.com/861/42814282105_85032f638b_b.... [2] https://news.yale.edu/2013/01/04/study-suggests-effect-fructose-brain-may-promote-overeating https://news.yale.edu/2013/01/04/study-suggests-effect-fruct...
- PaulKeeble 5y ago
  The paper deals with sugar intake and carbohydrates generally, total population in take of sugar has actually decreased substantially in the last 20 years but it had no effect on obesity which has carried on climbing. Its not the only evidence on this they present.
cactus2093 5y ago
This was an interesting read, but they really took some liberties in building up their case about why traditional explanations are so wrong. For instance, they never really refute the very common claim that it's the sugar & high fructose corn syrup in our diets. They attempt to refute it by comparing incredibly rare populations of modern hunter gathers that eat exclusively honey vs ones that don't, and then apparently make the leap that this difference must also apply to non-hunter gatherer societies? That makes zero sense, every single part of our modern lives are unrecognizably different from that of hunter gatherers. They also gloss over the purely thermodynamic aspect. There is a bit of discussion in the CICO section about how your body can do tricks to store more or less of the calories you eat. They they say people exercise more than they used to but are still gaining wait. Ok, but is that added exercise enough to burn off the added calories that they're eating? Clearly not, and it almost seems like a purposeful misdirection to set it up in this way without mentioning that there is a relatively simple basic calorie equation does, in fact, need to balance as a fundamental law of physics. There likely is something to the ideas that either people's base metabolic rates have declined, or something has tampered with our self-control or is impeding our natural impulse to stop eating at the right time. And it's a very interesting topic. But this over-the-top "mystery" angle really weakens the rest of their points.
- cm2012 5y ago
  The biggest evidence in the article against sugar and carbs being the cause is that US sugar and carb consumption (including hfcs) has gone down dramatically since 2000 but obesity has gone up dramatically.
zackmorris 5y ago
I've mostly stopped engaging online, but this is something that I'm passionate about after going through digestive issues that led to a severe burnout in 2019 which left me unable to work for about 6 months. There was a gut-serotonin connection there that I still don't fully understand. A few data points: * the radiation levels where I live in southern Idaho were 80 times higher than normal after Fukushima, so some of us may have received an additional lifetime dose of radiation in 2011 (we'll never know because they stopped reporting radiation levels) * some proteins like gluten (and the larger lectin family) are similar to ones in the thyroid and trigger the immune system against it, which could lead to or exacerbate diseases like Hashimoto's * lectins in legumes and nightshades trigger the lining of the intestines to release, allowing bad bacteria and toxins to cross the intestinal epithelium * sugar is toxic in large quantities and acts like alcohol in the body, causing obesity, organ damage and possibly even insulin resistance * GMO crops contain compounds not found in the human diet, in plants, or even in nature. these are probably in trace amounts, but combined with the gut flora disruptive effects of glyphosate, could trigger autoimmune responses * many preservatives like sodium benzoate are mutagenic and will either be found to be carcinogenic soon or are already banned in Europe and elsewhere * our definition of macronutrients is too broad, so one fat like omega 6 might be substantially more harmful than 3 or 9. the same goes for carbohydrates and even proteins * our bodies don't hold fat because they need it, but because they are disrupted by the extreme levels of cortisol we carry in the modern rat race, and because they have no place else to store the toxins that we eat, drink and breathe * to a first-order approximation, most people get no exercise, so miss out on the regenerative cellular machinery that only activates during stress. so now ideas like intermittent fasting distract us from stuff that actually works like pumping iron * medical science mostly focuses on averages, and single causes for illness, so almost completely ignores holistic effects or even the basics like tracking net calorie intake instead of gross There are so many dangers like this being obfuscated by the mainstream media that I could spend the rest of my days listing them. I'm more than 50% confident about them, but feel free to investigate. We don't have epidemiologic studies for most of this stuff yet, so I can only go by correlations and advice from experts. But the more I learn about obesity and my own struggles to regain my health, the more I'm convinced that most nutrition advice is completely wrong. Obesity has less to do with personal responsibility and calorie deficits than with the breakdown of our food supply. Fixing it will require systems-level thinking. The starting point is to ban organic food. That may sound extreme, but we can not as a healthy society allow a two-tier food supply to be a thing. We're looking at a future where all of the hard-working people doing the physical labor that runs the world are forced to live on substandard food and die early of preventable illnesses. Sure, scientists have the intelligence to "improve" food, but they don't have the wisdom or experience to understand the ramifications of the choices their egos make. And they certainly don't have the stomach to afford the liability insurance to cover the trillion dollar medical bill we're all now saddled with. My partner and I have chosen to buy mainly organic food now for these reasons and more. But it breaks my heart to think about the billions of people who can't afford it. I feel a great sense of shame for the academics and leaders who led us down this path.
keithwhor 5y ago
This is a really neat and well-researched paper. If you're looking for the summary, the most likely contaminants contributing to the obesity epidemic as identified by the authors are: (1) antibiotics in livestock that accumulate in both food and water supplies, (2) Per- and polyfluoroalkyl substances (PFAS) which are ubiquitous and hard to destroy and (3) Lithium in the water supply. The authors paint a convincing picture of why the obesity epidemic almost certainly is a result of environmental contaminants. This includes, but is not limited to (weakest to strongest, IMO); - The research on modern diets showing they're most ineffectual - Animals are getting predictably fatter at the same rates as humans in urban areas, and this is increasing - The concept of lipostasis: human bodies having a set point of fat storage and the research around it - Historically population BMI grew very slowly, starting at around 23, to suddenly ramp up unabated around the 1970s-80s - Areas further away from primary watersheds (where water can pick up more contaminants) tend to have higher population BMIs as a function of distance traveled from watershed - Lithium production was basically nonexistent until the 50s and spiked in the 70s-80s - Lithium is directly correlated with weight gain (primary research provided) and areas with water testing higher in Lithium have higher population BMIs ... and a lot more. It's worth a read. I think anybody that's overweight should still index heavily on diet and exercise (even if there's a contaminant, it seems unavoidable), but it's interesting.
- PaulKeeble 5y ago
  Does suggest that filtering the water and eliminating meat consumption that has been exposed to antibiotics is a good idea and in there somewhere might be the actual answer that genuinely helps someone loose weight. It is no more crazy than telling them to diet given that is shown not to actually work. It is arguably more effective to tell them to do something unproven but could actually work if its a contamination.
cm2012 5y ago
This is an incredible and fascinating article. I can't recommend it enough.
keithwhor 5y ago
Ha -- I made another post summarizing the contents of this paper, but read another poster suggesting that it could be correlated with cigarettes, as nicotine is an appetite suppressant. The authors of this paper suggest that the obesity trend started ramping up in the 70s - 80s and has continued unabated. Sure enough, this is directly negatively correlated with tobacco consumption per capita. https://cancercontrol.cancer.gov/sites/default/files/2020-06/m8_2_0.pdf https://cancercontrol.cancer.gov/sites/default/files/2020-06... I'm surprised the authors didn't touch on this -- it's a really thorough research paper. I have to imagine that nicotine consumption (or lack thereof) is directly correlated with obesity considering it's both a neurochemical (something the authors were suggesting as a contaminant), we know it affects appetite (it's a stimulant), and those most prone to smoking are also most prone to obesity (remove cigarettes = more food intake).
- netizen-936824 5y ago
  Or maybe food companies saw what tobacco companies had done with great success (formulating products that cause continual redosing/eating) The timing is right for that as well. Quite profitable when your customers can't stop consuming your products, no?
- nootropicat 5y ago
  That's a good hypothesis that appears to be incompatible with the data. In particular, Kuwait and Oman, similar on an ethnic basis, with smoking much more prevalent in Kuwait with a much higher obesity rate. Oman is actually richer per capita so it's not like they can't afford treats while Kuwaitis can. Of course, it's just one data point, maybe countries with higher smoking percentage are indeed fatter on average. https://worldpopulationreview.com/country-rankings/smoking-rates-by-country https://worldpopulationreview.com/country-rankings/smoking-r... https://www.omanobserver.om/article/88477/Local/alarming-rise-in-obesity-rate-in-region https://www.omanobserver.om/article/88477/Local/alarming-ris...
  - nootropicat 5y ago
    Oman isn't actually richer, that part was incorrect.
allturtles 5y ago
I find their dismissal of calories-in/calories-out pretty unconvincing: > Pew says calorie intake in the US increased from 2,025 calories per day in 1970 to about 2,481 calories per day in 2010 [45]. The USDA Economic Research Service estimates that calorie intake in the US increased from 2,016 calories per day in 1970 to about 2,390 calories per day in 2014 [46]. Neither of these are jaw-dropping increases. > If we go back further, the story actually becomes even more interesting. Based on estimates from nutrient availability data, Americans actually ate more calories in 1909 than they did in 1960. A 25% increase in energy intake for the same biology is not jaw-dropping? Maybe not, but it seems like a lot to me, and a plausible explanation on its face. I need a lot more convincing that this is not the answer right here. Going back to 1909 for evidence of higher energy intake is not convincing either, most people at that time did hard physical labor every day - on a farm or in a factory.
- amanaplanacanal 5y ago
  So even if we accept that 25% increase, why are people eating 25% more than they were before? It sounds like this paper is pointing to some possible answers.
amai 5y ago
It must be something specific to the US, because outside the US there is no obesity epidemic. https://ourworldindata.org/grapher/share-of-adults-defined-as-obese https://ourworldindata.org/grapher/share-of-adults-defined-a...
- remexre 5y ago
  The paper explains a mechanism for why the Middle East is also seeing extremely high rates of obesity -- and I wouldn't call Europe's or South America's 20s-ish% rate from your chart "no obesity epidemic" either...
nikolay 5y ago
The issue is multi-faceted and more than the sum of all parts. Lack of quality sleep, low-nutrition high-calorie foods, less exposure to sunlight, eating all day long, and many others lead to the accumulation of fat. I do Orthodox Fasting where I don't eat anything for 5.5 days and don't drink water during the first 3 days - and I don't lose any weight. But I get lethargic. So, obviously, the fat in our bodies has became less mobile. When we don't eat, we don't burn it for energy, we just become lethargic, and we need to find exactly why this happens, because it's the key to this issue.
RappingBoomer 5y ago
fascinating read...i bought into his theory right away
mleonhard 5y ago
SF water has no PFAs [2]. Bay Area groundwater has lithium. San Jose groundwater had 2 ppb lithium in 1964 [5]. Santa Clara groundwater now has 5-10 ppb lithium [4]. SF has several aquifers. In 2017, SFPUC started using 4 mgd (million gallons per day) of groundwater from these aquifers [0]. SFPUC delivers 60 mgd to SF retail customers [1], so groundwater comprises 10% and the remaining 90% comes from Hetch Hetchy via pipeline [3]. I found no direct measurement of Lithium in Hetch Hetchy water. SF fills its reservoirs with Hetch Hetchy water [6]. These reservoirs had about 1 ppb of lithium in 1965 [5]. I expect Hetch Hetchy's lithium levels are unchanged. TLDR: SF water has 1 ppb (1 ng/mL) lithium and no PFAs. [0] https://www.sfpuc.org/programs/water-supply/groundwater https://www.sfpuc.org/programs/water-supply/groundwater [1] https://sfwater.org/Modules/ShowDocument.aspx?documentid=14560 https://sfwater.org/Modules/ShowDocument.aspx?documentid=145... [2] https://sfpuc.org/sites/default/files/accounts-and-services/water-quality/20210525-SF_WaterQualityReport.pdf https://sfpuc.org/sites/default/files/accounts-and-services/... [3] https://www.sfpuc.org/sites/default/files/about-us/watersupplymap_092118.pdf https://www.sfpuc.org/sites/default/files/about-us/watersupp... [4] https://www.valleywater.org/sites/default/files/2018-08/2017%20Groundwater%20Quality%20Report_Web.pdf https://www.valleywater.org/sites/default/files/2018-08/2017... [5] https://pubs.usgs.gov/wsp/1812/report.pdf https://pubs.usgs.gov/wsp/1812/report.pdf [6] https://en.wikipedia.org/wiki/Hetch_Hetchy https://en.wikipedia.org/wiki/Hetch_Hetchy

89 points by jasonhansel 5y ago

I was looking forward to this. It's the conclusion to a discussion posted here earlier [1]. 1. https://news.ycombinator.com/item?id=27796557 https://news.ycombinator.com/item?id=27796557

retrac 5y ago

Edit: The following is mostly a non sequitur. My response was based in part on a misreading of the article's arguments. They're concerned primarily with the "consolidation" of obesity since about 1980 without any obvious changes for why. The changes for why were in the previous decades and the chickens should have come home to roost by 1980. Yet we are indeed much more obese than in 1980 but not more sedentary. So... why? This I have to say, is in fact somewhat mysterious. I have a contention with the "obesity hasn't been reversed in any population" claim. Here in Canada, child obesity has in fact decreased in recent years, after several decades of continual increases. Given that childhood obesity, and obesity in general, has been a major social issue everyone is aware of and has been working hard on (I assume), the small decrease in proportion to the amount of energy invested, is rather depressing. Still, maybe cause for some hope. > Something seems to have changed. But surprisingly, we don’t seem to have any idea what that thing was. We don't? While exactly how much this is a factor is contended, I thought it was near-consensus at this point that it's because we are less physically active. The timeline certainly fits - beginning about 1890 and ending about 1975 -- that is the period from the beginning to universal adoption of the car. Between home appliances, powered vehicles and industrial automation, many modern people don't actually have to do anything physical. Hauling their corporeal form between various chairs is literally all the exercise many people get. This would be unfathomable to my great-grandparents. They walked to the store then hauled the groceries home. They walked a few miles every Sunday to go to church. They walked to work. They tended the fields largely with manual labour and a horse. They mowed the garden and yard, by hand. Every nail in the home, driven by hand. Ground meat for dinner? Minced by hand. And by then, industrialization had already completely changed things for them, to their own grandparents, giving them what they must have thought an amazing amount of free time and leisure. (My great-grandparents clothes were almost certainly machine-woven, for example.) If we're eating as many calories, or slightly more, as our grandparents did, while barely moving in comparison to them, is it any surprise we all got really fat? In fairness to the paper, I suppose one could view this social change as a mimetic contagion of a sort.

chillpenguin 5y ago
I'm pretty sure we are eating more calories than our grandparents did, too. Portion sizes for common things are much larger now. You can look at muffin sizes for example and how the average muffin is physically larger today. Same with burgers, soft-drink cup sizes, etc. But yeah I agree with everything you said as well regarding lack of physical exercise.
- krona 5y ago
  > I'm pretty sure we are eating more calories than our grandparents did, too It varies from country to country. In the UK for instance, calories per household decreased 15-30% from 1980 to 2009 (https://ifs.org.uk/bns/bn142.pdf https://ifs.org.uk/bns/bn142.pdf). The trend has continued since.
yeuxardents 5y ago
Certainly the addition of ubiquitous sugary snacks and drinks everywhere as well contributes, how is that discounted so easily. So much processed food within a 2 minute car rides reach, and it only require 30 paces into and out of the store for 2000kcals in treats!
nickthemagicman 5y ago
This is certainly true from an personal anecdotal perspective. The minute I went from college where I was very active to an office job the pounds piled on. What's interesting is that if you're poor modern Capitalism doesn't allow much free time to exercise, which might explain why the obesity epidemic effects the poor more.
zosima 5y ago
The mystery is not the modest increase of obesity from 1890 to 1975. This increase is very likely caused by reduced activity and increased caloric consumption. It is the dramatic increase in obesity from around 1980 and onward that is a mystery. And part of the mystery is that animals living around humans, in the wild or in the lab, seems to have gone through a similar increase in body weight. The article goes through why this dramatic increase can not just be due to reduced exercise or increased caloric consumption, but must have some other, unknown factors, to explain it.

trhway 5y ago

>So what changed in 1980? Effects of the agriculture policies starting 1973 which resulted in HFCS everywhere? Including sugar replacement with HFCS due to tariffs https://scholarworks.montana.edu/xmlui/bitstream/handle/1/2554/WiltgenT1207.pdf https://scholarworks.montana.edu/xmlui/bitstream/handle/1/25... "On the demand side, high fructose corn syrup (HFCS) was beginning to make inroads as food and beverage manufacturers sought to replace sugar with a less expensive input. As prices dropped, the International Trade Commission opened hearings to determine whether or not imports were the source of “serious injury or threat thereof” (USDA, December 1976, 15) to the domestic industry and, in March 1977, recommended that imports be restricted. President Ford, anticipating this recommendation, increased the tariff on raw sugar from 0.625 cents to 1.875 cents per pound in September 1976. When the 1977 Food and Agriculture Act took effect on November 8, 1977, a price support/ loan rate program was established (see “Price Support Loan” section). To reduce government expenditures on this new program, President Carter raised import fees to 2.7 cents per pound for raw sugar and 3.22 cents for refined sugar. The import fee, coupled with the import duty, served to control imports in the late 1970s. Both the fee and duty reached their peaks in early 1979, when the fee for raw sugar was 3.22 cents and the import duty was 2.8125 cents per pound. "

PaulHoule 5y ago
Or glyphosate and/or neonicotinoids.
smegcicle 5y ago
preservatives prevent the natural breakdown of food, so it doesn't seem surprising that they could have a negative effect on digestion

getpost 5y ago

My money (and my dietary choices) are on excess PUFA as a key contributor to obesity. https://www.youtube.com/watch?v=pHnPinYI2Yc https://www.youtube.com/watch?v=pHnPinYI2Yc https://fireinabottle.net/torpor-sloth-and-gluttony-scd1-causes-humans-to-store-fat/ https://fireinabottle.net/torpor-sloth-and-gluttony-scd1-cau...

alejohausner 5y ago
Polyunsaturated fats are known to suppress thyroid function, this leading to lowered metabolism and weight gain. A quick search brought up this: ANTI-THROID EFFECTS OF PUFAS (POLYUNSATURATED FATS) AND HERBS January 2012 Trakya University Journal of Natural Sciences 13(2) Authors: Başar Altınterim Malatya Turgut Özal University
jnwatson 5y ago
This is consistent with the elbow of the increase in obesity being about 1980. Canola oil was invented in the 1970's and really hit its stride in the US in the 1980's.
nikolay 5y ago
According to Ray Peat, any amount of PUFA is toxic, but especially so in quantities of more than a gram a day. And most of us today get tons more than 1g. One of the reasons is the desaturation of cardiolipin in mitochondria, leading to instability and dysfunction.

DiabloD3 5y ago

I prefer the other theory I've heard: the body's gauge on starvation is not based on caloric intake, but based on nutritional intake; ergo, low nutrition diets that have sufficient calories (such as the Standard American Diet) make the body think winter is coming soon, and time to get extra plump. This is mainly the basis of my dieting. I reached a peak of 340, and in exactly a year, while maintaining the same CICO, but changing from the SAD to strict non-Keto Paleo, became 214, and then eventually slimmed down to the 175-185 range. I now eat mainly focused on nutritional density, and keeping the weight off is easy.

nickff 5y ago
CICO meaning calories-in-calories-out? Please avoid undefined and uncommon acronyms. Did you do food diaries/journals as you increased weight, and as you lost weight? I have lost significant amounts of weight by reducing caloric intake, and noticed that my records on the way up and down were very different.
- thefourthchime 5y ago
  I believe so. It sounds like he doing paleo without keto. I may be wrong, but basically just eat food on the perimeter of the super market. Veggies, meat, dairy. Nothing processed.
- temp_praneshp 5y ago
  In this context, it's a common acronym. Maybe you are just not as well read in this area as in others? Googling CICO on an incognito window are 100% hits for calories-in-calories-out.
  - nickff 5y ago
    That's how I figured it out, but I consider 'this context' to be Hacker News, where 'API' is common, but 'CICO' is not.
    - imwillofficial 5y ago

xxxtentachyon 5y ago

This might have been covered in some part I skimmed over, but they never seemed to offer a mechanism for contaminated water in a drainage basin entering the local food supply via processed foods in a way that wouldn’t also impact a plant-based (e.g. potato-only) diet. Did anyone get any insight there or is that really a gap in their explanation? As an aside, I have an unfortunate and deep association between Microsoft Word-typesetting and graphs with papers I wrote in high school that put me in a skeptical stance from the start

joe_the_user 5y ago
The thing about the article is it's not really offering any air tight explanations. It looks at a significant amount of data and asks what's correlated and what isn't - many common explanations simply don't fit the data at all. So it comes down to contaminants and psychological effects. But it is not making any definitive pronouncements about which contaminants or how.
jeffbee 5y ago
What makes you suspect this was typeset in Word?
jaggederest 5y ago
You have to segment the claims in two: Claim one (We have eliminated mechanisms aside from contamination for the obesity epidemic) rests essentially on anthropological studies with "uncontaminated" populations and conversely on the fact that animals in close contact with humans are also becoming obese rapidly even when holding calories constant (e.g. lab rats) Claim two posits some substances that might be responsible, and I think roughly is oriented around: a) antibiotics are intensively used in animal cultivation in a way that might leak into the food supply and water table downstream. b) PFAS accumulate biologically after exposure at parts-per-billion levels, and become increasingly more concentrated as you go up the food chain and downstream, but e.g. potatoes are not exposed to enough PFAS to hit the thresholds for deleterious effects. c) I don't think that lithium is actively taken up by plants to the degree that would affect pure unprocessed plant consumption, it's mostly about direct exposure and water contamination downstream. I think the claim one hypothesis is really strong. I've had a similar hypothesis for a few years now, though mine was more oriented around infection than contagion, but similar in terms of structure - the more people you put close together the more likely they are to cross-contaminate with some substance that makes them obese, and the clearer difference we have between baseline humanity ~100y ago and modern ones suffering from the obesity epidemic. I think the claim two hypothesis is a little bit weaker, but it's interesting that they have 3 proposed mechanisms that range from known effect, known presence (antibiotics), known presence but unknown effect (PFAS), and unknown presence but known effect (lithium), so I think they roughly descend in order of likelihood of explaining the obesity epidemic. I would guess, obviously, the answer is "all three", based just on the severity of the epidemic, but I'd guess it's quite likely antibiotics have a small effect, and also somewhat likely PFAS have a large effect, while I think the lithium hypothesis is the weakest of the three, but would be interesting to analyze further.

Gatsky 5y ago

From meticulously monitoring macronutrients and body composition over periods of 3 months, I find I can eat say 3/4rs of my calculated energy requirements and still get slowly fatter over time. This slow fattening effect is associated with poor sleep, occasional massive calorie bombs due to social events and, for me at least, eating a lot of starches often in snack foods. The sleep is particularly important, when deprived I develop incessant cravings for low quality food. If I sleep well and restrict carbs, I can lose 5kg+ without trying despite no exercise.

axiosgunnar 5y ago
It‘s a good point. Sleep more :-)

ellyagg 5y ago

What kind of proof would it take for people to agree that the obesity epidemic is due to food being dramatically cheaper and more palatable than in our environment of evolutionary adaptedness?

brianberns 5y ago
Did you read the linked paper? They consider this possibility and reject it.
- ellyagg 5y ago
  Sure. Did you realize that epistemically they don't have the power to reject explanations? It would certainly be news to Stephan Guyenet if they did have in this case.
imtringued 5y ago
Distance to cheap food stores vs organic stores.
kixiQu 5y ago
How would that explain lab animals gaining weight?
- ellyagg 5y ago
  The most likely explanation for this is some combination of 1) lab animals being fed more over time because researchers themsevles have been normalized to bigger food portions, 2) incomparable data of lab animals feeding over time, and 3) fraud because of the pressure to show unusual results.
  - kixiQu 5y ago
    The theory calories-in-calories-out doesn't explain why animals fed controlled diets over time could exhibit a change in weight, pretty much by definition. So instead of trying to extend that paradigm in some way that would explain it -- or even to acknowledge that there could be some auxiliary cause for this phenomenon while saying it's irrelevant to the trends in human obesity, which I think would be a fair argument -- you're saying 1) they aren't actually being fed the same thing, 2) they aren't actually being fed the same thing, 3) they aren't actually being fed the same thing or they aren't actually gaining weight. This is only "most likely" if you begin by assuming the truth of what's to be proved, i.e., begging the question.

zelienople 5y ago

Nonsense. Utter rubbish. People are fat because they eat more calories than they burn. The only reason that studies do not reflect this is that they rely largely upon self-reporting and people lie.

542458 5y ago
That’s not quite true. Your body can decide to do different things with the calories it gets, including storing them. There appear to be a number of things that influence if and how calories are stored, including the source/type of the calories in question. There’s also evidence that gut micro biome affects our ability to absorb calories and what happens to those calories once absorbed. Furthermore, there’s a large question as to why people eat so many calories. After all, we don’t typically see people drink water until they die. What biological process makes food different, that people are willing to overeat? Saying “people are fat because they eat too many calories” is like saying “that building collapsed because of gravity” - true, but not particularly useful when trying to get to the root of things. https://www.scientificamerican.com/article/how-lab-rats-are-changing-our-view-of-obesity/ https://www.scientificamerican.com/article/how-lab-rats-are-...
- thebooktocome 5y ago
  I agree with you, but I think it's too charitable to assume that the goal in this societal conversation is "Getting to the root cause of obesity". Many people would rather ignore any evidence contrary to absolute, individual culpability and commence with the victim-blaming.
bluedays 5y ago
So like… you got some sorts credentials?
deleted 5y ago
[deleted]
joe_the_user 5y ago
The article cites the results of a number of studies in which people were direct observed.

kelvin0 5y ago

During the 1970s High Fructose corn syrup seems to have kicked off the issue. Low fat was the rage then, and companies needed something to add 'taste' to their various process foods. https://en.wikipedia.org/wiki/High-fructose_corn_syrup https://en.wikipedia.org/wiki/High-fructose_corn_syrup

maxk42 5y ago

Surprised nobody in this thread has brought up the link between obesity and increase in dietary sugar intake. [1] More and more research seems to show that replacing dietary fats with sugars is closely correlated to obesity levels. Most notably, fructose seems to be difficult for the body to metabolize since it has no impact on feelings of satiety. [2] [1] https://farm1.staticflickr.com/861/42814282105_85032f638b_b.jpg https://farm1.staticflickr.com/861/42814282105_85032f638b_b.... [2] https://news.yale.edu/2013/01/04/study-suggests-effect-fructose-brain-may-promote-overeating https://news.yale.edu/2013/01/04/study-suggests-effect-fruct...

PaulKeeble 5y ago
The paper deals with sugar intake and carbohydrates generally, total population in take of sugar has actually decreased substantially in the last 20 years but it had no effect on obesity which has carried on climbing. Its not the only evidence on this they present.

cactus2093 5y ago

This was an interesting read, but they really took some liberties in building up their case about why traditional explanations are so wrong. For instance, they never really refute the very common claim that it's the sugar & high fructose corn syrup in our diets. They attempt to refute it by comparing incredibly rare populations of modern hunter gathers that eat exclusively honey vs ones that don't, and then apparently make the leap that this difference must also apply to non-hunter gatherer societies? That makes zero sense, every single part of our modern lives are unrecognizably different from that of hunter gatherers. They also gloss over the purely thermodynamic aspect. There is a bit of discussion in the CICO section about how your body can do tricks to store more or less of the calories you eat. They they say people exercise more than they used to but are still gaining wait. Ok, but is that added exercise enough to burn off the added calories that they're eating? Clearly not, and it almost seems like a purposeful misdirection to set it up in this way without mentioning that there is a relatively simple basic calorie equation does, in fact, need to balance as a fundamental law of physics. There likely is something to the ideas that either people's base metabolic rates have declined, or something has tampered with our self-control or is impeding our natural impulse to stop eating at the right time. And it's a very interesting topic. But this over-the-top "mystery" angle really weakens the rest of their points.

cm2012 5y ago
The biggest evidence in the article against sugar and carbs being the cause is that US sugar and carb consumption (including hfcs) has gone down dramatically since 2000 but obesity has gone up dramatically.

zackmorris 5y ago

I've mostly stopped engaging online, but this is something that I'm passionate about after going through digestive issues that led to a severe burnout in 2019 which left me unable to work for about 6 months. There was a gut-serotonin connection there that I still don't fully understand. A few data points: * the radiation levels where I live in southern Idaho were 80 times higher than normal after Fukushima, so some of us may have received an additional lifetime dose of radiation in 2011 (we'll never know because they stopped reporting radiation levels) * some proteins like gluten (and the larger lectin family) are similar to ones in the thyroid and trigger the immune system against it, which could lead to or exacerbate diseases like Hashimoto's * lectins in legumes and nightshades trigger the lining of the intestines to release, allowing bad bacteria and toxins to cross the intestinal epithelium * sugar is toxic in large quantities and acts like alcohol in the body, causing obesity, organ damage and possibly even insulin resistance * GMO crops contain compounds not found in the human diet, in plants, or even in nature. these are probably in trace amounts, but combined with the gut flora disruptive effects of glyphosate, could trigger autoimmune responses * many preservatives like sodium benzoate are mutagenic and will either be found to be carcinogenic soon or are already banned in Europe and elsewhere * our definition of macronutrients is too broad, so one fat like omega 6 might be substantially more harmful than 3 or 9. the same goes for carbohydrates and even proteins * our bodies don't hold fat because they need it, but because they are disrupted by the extreme levels of cortisol we carry in the modern rat race, and because they have no place else to store the toxins that we eat, drink and breathe * to a first-order approximation, most people get no exercise, so miss out on the regenerative cellular machinery that only activates during stress. so now ideas like intermittent fasting distract us from stuff that actually works like pumping iron * medical science mostly focuses on averages, and single causes for illness, so almost completely ignores holistic effects or even the basics like tracking net calorie intake instead of gross There are so many dangers like this being obfuscated by the mainstream media that I could spend the rest of my days listing them. I'm more than 50% confident about them, but feel free to investigate. We don't have epidemiologic studies for most of this stuff yet, so I can only go by correlations and advice from experts. But the more I learn about obesity and my own struggles to regain my health, the more I'm convinced that most nutrition advice is completely wrong. Obesity has less to do with personal responsibility and calorie deficits than with the breakdown of our food supply. Fixing it will require systems-level thinking. The starting point is to ban organic food. That may sound extreme, but we can not as a healthy society allow a two-tier food supply to be a thing. We're looking at a future where all of the hard-working people doing the physical labor that runs the world are forced to live on substandard food and die early of preventable illnesses. Sure, scientists have the intelligence to "improve" food, but they don't have the wisdom or experience to understand the ramifications of the choices their egos make. And they certainly don't have the stomach to afford the liability insurance to cover the trillion dollar medical bill we're all now saddled with. My partner and I have chosen to buy mainly organic food now for these reasons and more. But it breaks my heart to think about the billions of people who can't afford it. I feel a great sense of shame for the academics and leaders who led us down this path.

keithwhor 5y ago

This is a really neat and well-researched paper. If you're looking for the summary, the most likely contaminants contributing to the obesity epidemic as identified by the authors are: (1) antibiotics in livestock that accumulate in both food and water supplies, (2) Per- and polyfluoroalkyl substances (PFAS) which are ubiquitous and hard to destroy and (3) Lithium in the water supply. The authors paint a convincing picture of why the obesity epidemic almost certainly is a result of environmental contaminants. This includes, but is not limited to (weakest to strongest, IMO); - The research on modern diets showing they're most ineffectual - Animals are getting predictably fatter at the same rates as humans in urban areas, and this is increasing - The concept of lipostasis: human bodies having a set point of fat storage and the research around it - Historically population BMI grew very slowly, starting at around 23, to suddenly ramp up unabated around the 1970s-80s - Areas further away from primary watersheds (where water can pick up more contaminants) tend to have higher population BMIs as a function of distance traveled from watershed - Lithium production was basically nonexistent until the 50s and spiked in the 70s-80s - Lithium is directly correlated with weight gain (primary research provided) and areas with water testing higher in Lithium have higher population BMIs ... and a lot more. It's worth a read. I think anybody that's overweight should still index heavily on diet and exercise (even if there's a contaminant, it seems unavoidable), but it's interesting.

PaulKeeble 5y ago
Does suggest that filtering the water and eliminating meat consumption that has been exposed to antibiotics is a good idea and in there somewhere might be the actual answer that genuinely helps someone loose weight. It is no more crazy than telling them to diet given that is shown not to actually work. It is arguably more effective to tell them to do something unproven but could actually work if its a contamination.

cm2012 5y ago

This is an incredible and fascinating article. I can't recommend it enough.

keithwhor 5y ago

Ha -- I made another post summarizing the contents of this paper, but read another poster suggesting that it could be correlated with cigarettes, as nicotine is an appetite suppressant. The authors of this paper suggest that the obesity trend started ramping up in the 70s - 80s and has continued unabated. Sure enough, this is directly negatively correlated with tobacco consumption per capita. https://cancercontrol.cancer.gov/sites/default/files/2020-06/m8_2_0.pdf https://cancercontrol.cancer.gov/sites/default/files/2020-06... I'm surprised the authors didn't touch on this -- it's a really thorough research paper. I have to imagine that nicotine consumption (or lack thereof) is directly correlated with obesity considering it's both a neurochemical (something the authors were suggesting as a contaminant), we know it affects appetite (it's a stimulant), and those most prone to smoking are also most prone to obesity (remove cigarettes = more food intake).

netizen-936824 5y ago
Or maybe food companies saw what tobacco companies had done with great success (formulating products that cause continual redosing/eating) The timing is right for that as well. Quite profitable when your customers can't stop consuming your products, no?
nootropicat 5y ago
That's a good hypothesis that appears to be incompatible with the data. In particular, Kuwait and Oman, similar on an ethnic basis, with smoking much more prevalent in Kuwait with a much higher obesity rate. Oman is actually richer per capita so it's not like they can't afford treats while Kuwaitis can. Of course, it's just one data point, maybe countries with higher smoking percentage are indeed fatter on average. https://worldpopulationreview.com/country-rankings/smoking-rates-by-country https://worldpopulationreview.com/country-rankings/smoking-r... https://www.omanobserver.om/article/88477/Local/alarming-rise-in-obesity-rate-in-region https://www.omanobserver.om/article/88477/Local/alarming-ris...
- nootropicat 5y ago
  Oman isn't actually richer, that part was incorrect.

allturtles 5y ago

I find their dismissal of calories-in/calories-out pretty unconvincing: > Pew says calorie intake in the US increased from 2,025 calories per day in 1970 to about 2,481 calories per day in 2010 [45]. The USDA Economic Research Service estimates that calorie intake in the US increased from 2,016 calories per day in 1970 to about 2,390 calories per day in 2014 [46]. Neither of these are jaw-dropping increases. > If we go back further, the story actually becomes even more interesting. Based on estimates from nutrient availability data, Americans actually ate more calories in 1909 than they did in 1960. A 25% increase in energy intake for the same biology is not jaw-dropping? Maybe not, but it seems like a lot to me, and a plausible explanation on its face. I need a lot more convincing that this is not the answer right here. Going back to 1909 for evidence of higher energy intake is not convincing either, most people at that time did hard physical labor every day - on a farm or in a factory.

amanaplanacanal 5y ago
So even if we accept that 25% increase, why are people eating 25% more than they were before? It sounds like this paper is pointing to some possible answers.

amai 5y ago

It must be something specific to the US, because outside the US there is no obesity epidemic. https://ourworldindata.org/grapher/share-of-adults-defined-as-obese https://ourworldindata.org/grapher/share-of-adults-defined-a...

remexre 5y ago
The paper explains a mechanism for why the Middle East is also seeing extremely high rates of obesity -- and I wouldn't call Europe's or South America's 20s-ish% rate from your chart "no obesity epidemic" either...

nikolay 5y ago

The issue is multi-faceted and more than the sum of all parts. Lack of quality sleep, low-nutrition high-calorie foods, less exposure to sunlight, eating all day long, and many others lead to the accumulation of fat. I do Orthodox Fasting where I don't eat anything for 5.5 days and don't drink water during the first 3 days - and I don't lose any weight. But I get lethargic. So, obviously, the fat in our bodies has became less mobile. When we don't eat, we don't burn it for energy, we just become lethargic, and we need to find exactly why this happens, because it's the key to this issue.

RappingBoomer 5y ago

fascinating read...i bought into his theory right away

mleonhard 5y ago

SF water has no PFAs [2]. Bay Area groundwater has lithium. San Jose groundwater had 2 ppb lithium in 1964 [5]. Santa Clara groundwater now has 5-10 ppb lithium [4]. SF has several aquifers. In 2017, SFPUC started using 4 mgd (million gallons per day) of groundwater from these aquifers [0]. SFPUC delivers 60 mgd to SF retail customers [1], so groundwater comprises 10% and the remaining 90% comes from Hetch Hetchy via pipeline [3]. I found no direct measurement of Lithium in Hetch Hetchy water. SF fills its reservoirs with Hetch Hetchy water [6]. These reservoirs had about 1 ppb of lithium in 1965 [5]. I expect Hetch Hetchy's lithium levels are unchanged. TLDR: SF water has 1 ppb (1 ng/mL) lithium and no PFAs. [0] https://www.sfpuc.org/programs/water-supply/groundwater https://www.sfpuc.org/programs/water-supply/groundwater [1] https://sfwater.org/Modules/ShowDocument.aspx?documentid=14560 https://sfwater.org/Modules/ShowDocument.aspx?documentid=145... [2] https://sfpuc.org/sites/default/files/accounts-and-services/water-quality/20210525-SF_WaterQualityReport.pdf https://sfpuc.org/sites/default/files/accounts-and-services/... [3] https://www.sfpuc.org/sites/default/files/about-us/watersupplymap_092118.pdf https://www.sfpuc.org/sites/default/files/about-us/watersupp... [4] https://www.valleywater.org/sites/default/files/2018-08/2017%20Groundwater%20Quality%20Report_Web.pdf https://www.valleywater.org/sites/default/files/2018-08/2017... [5] https://pubs.usgs.gov/wsp/1812/report.pdf https://pubs.usgs.gov/wsp/1812/report.pdf [6] https://en.wikipedia.org/wiki/Hetch_Hetchy https://en.wikipedia.org/wiki/Hetch_Hetchy