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The other major question I'm grappling with is why there is an obesity-elevation gradient.
A guy is going alone through the wilderness, with a solar powered icebox on his back. He crosses a raging river by swimming. He slashes his way through a jungle. He is blasted by sun on an endless desert. It's been weeks and he has no company at all, save the bleached bones (and ice boxes) of those who did not make it. He climbs a mountain until he finally comes to a cave in the snow. Inside is a man with beard like silvery horsehair, eyes like fire. Very old but fit as a mountain goat.
"O wise sensei, I brought your pizza and ice cream with me. Now tell me the secret of perfect health!"
"It is vely simple", says the old man while greedily unwrapping a stick of icecream. "Only meet with people who have made a journey such as you youlself just did."
More prosaically: "It" does not run uphill.
~90% of Earth's mammalian excreta is produced by humans and their livestock. The livestock especially are immobilized in close quarters and their manure is spread to fields by mechanical means. The manure is often in a fresh condition with viable gut flora present. This means that the fitness of the gut microbiome is independent of the host's mobility and fitness. They can find plenty of new hosts nearby, and have a good chance of spreading far and wide with tractors. If it can make the host eat x% more, it gains roughly that big an advantage: that much more manure along which it can spread. In state of nature that tactic obviously would not work, it would be much better to have a slim host with good legs.
Selection for larger animals, antibiotic feeding and selection by market forces could also contribute towards more hunger-inducing gut microbes.
Maybe overweight is not the only hit on the host's well-being. There could be other pathologies by which the mechanised microbes improve their fitness. If this is the case, exposure to bad manure – or biome that derives from it – would be a common cause for both obesity and some other diseases associated with it.
Of course if one insists on some of the assumptions you did not need, namely doing the standard microcanonical ensemble approach, it trivializes everything and no second law comes out.
In microcanonical ensemble the system is isolated, meaning its energy is fixed. Microstates are partitioned into a macrostates by their energy (stronger version of your assumption of macro being a function of micro), so they don't switch into a different macrostate. If you take them to be energy eigenstates, the microstates don't evolve either.
I don't endorse the idea of a macrostate secretly being in a certain microstate. They are different things, preparing a microstate takes a lot more effort.
When this phrase is used it is maybe implied that the equilibriating happens much faster and further than the actor (usually a democratic regulating body) expected, and that they are too slow to "evaluate medium term, make corrections".
One other potential benefit of an unstable mechanism is that there is no energy loss that comes with damping, in other words the many possible errors are not rejected as heat. Instead, the error can be measured with a much smaller energy cost, and then a reversible correction can be made that on average costs no energy. In concrete terms this can be pictured as replacing a dashpot or a shock absorber with a finely controlled quick response linear electric motor (one that can reproduce and correct any error that occurs). Of course a dashpot-like solution is usually simpler and more reliable. I have come to appreciate reliability even more as I've grown older.
Controlled experiments and a connected body of theory. The set-up of experiments needs to be freely adjustable to check that most particularities and circumstances of the experiment can indeed be ignored and what remains has qualities of a "natural law".
This is a strong definition, it somewhat excludes cosmology and a good deal of biology.
Xylitol seems to be a source of oxalic acid. I don't know if it metabolized into that form by the body or gut microbiome, or both, but it definitely shows up in urine. It says "Excessive use may cause laxative effects" on the bag of chewing gum, but I think oxalic acid is a much bigger concern with potential for long term damage to kidneys and joints. Highly processed vegetable rich diets might already contain excessive amounts, especially for people with gut problems and fat malabsorption.
If were talking about easy adjustments to fight caries, how about switching to porridge based breakfast (in place of cereals or muesli) and opting for 100% oat bread instead of dry white bread. This in my experience has a big effect on how much and for how long starchy matter adheres to fissures in teeth.
(I feel like I'm betraying Finland by attacking xylitol. I'm making up for that by talking up oats and porridge.)
Thank you for the information. Now I feel a lot safer when eating osso buco.
But why is it a ruminant species having these problems again? Why not chickens or whales or fish? Perhaps it's the grazing lifestyle combined with unnaturally high population densities and immobility. Or herbivores having low natural resistance to prion pathologies.
I believe the ultimate origin of bovine pathogenic prions is in high temperature processing of skins, offal, and especially CNS tissue and bones (prion is expressed in the marrow more than average). Remember, we used to feed bonemeal and other residues of bovine origins to cows until the mad cow episode. Some of that matter had gone through stages like rendering off the fat.
CWD might be a spillover from BSE or have an independent but similar origin.
Why not whales then? They have plenty of lifetime to manifest a prion disease if they get one. Whalers even used to process blubber on ships and tip the reject into sea. But, 1. oceans are immensely larger than pastures and fields, 2. the scale of processing was smaller than in 20th century bovine materials, and 3. nobody fed that material straight back to whales.
I like and respect cows and other ungulates, but they don't exactly live and die by their wits. A carnivore would have starved long before, and a bird flown into a wall, before we found one in a state in which we sometimes find elk or reindeer. So far the cases in Finland have been of a "non-transmissible" variety. However, the rate of occurence seems higher than in spontaneous Creutzfeld-Jakob disease (humans). A population on the order of 100k (of which only a small portion lives to an advanced age) and a few cases per year. Let's hope no-one buys American urine based deer attractant on Ebay.
Not to rain on any parades... but don't eat spinach guys.
If you try to fix joint pains by getting more protein from kilograms of spinach or kale, you will be severly disappointed. I'm talking about oxalic acid. See my comment.
It is more likely though that you will get kidney injury or kidney stones as a first symptom. Some people have died of imbibing big green smoothies, which presumably contained spinach. Everyone knows rhubarb is bad because of oxalic acid. Spinach contains the same stuff in high concentrations.
Congratulations on fixing your problem!
I have an alternative diagnosis though: Maybe it was gout? That is, sodium urate crystals causing inflammation and pain in or around the joints. Toe involvement would very much suggest that, also the fact that it improved relatively quickly with a change of diet. Hips are not the most characteristic complaint in gout but I know two guys in real life who are on low purine diets and one of them is doing it for his hips. Doctors also found clinical indications of wear in his hips when he was around your age, but almost 2 decades later he is still doing great amounts of physical work, just the kind of which is known to be very hard on the knees. He's not audibly complaining AFAIK. What I want to say with this is that a diagnosis of osteoarthritis is not necessarily the end of the world. It can be that too, of course.
And I also know one case like this in fiction! There's a Danish-Swedish television drama where one of the characters has scrotal pain and a mortal fear of testicular cancer. He goes to the doctor and is told to lay off the beans because of gout in the hips. Just something I'm primed to notice in TV playing in the background.
Did you eat a lot of beans and lentils before the switch to more animal protein? Legumes have a good amount of purines in them. You mentioned fish and maybe opportunistic meat eating too? Was that small fish with skins, such as herrings, sardines or whitefish? Did you eat organ meats? Liver for the B12?
You mentioned one-legged squats. Ballet dancers do all kinds of high torque one-legged movements hinged at the hip and they often have snapping hips and hip pain; this is maybe because of the tendons are overgrown or just irritated and swollen from having to move in inconventional paths. If the pain returns, try some symmetric lifting for a while.
You mentioned pain after sitting in a weird position. Was that bent forward? That along with lunges making it worse sounds like it's the iliopsoas and its tendons in the lower end. Also known as hip flexor or tenderloin. When it's feeling sore avoid rapid and jerking movements like spurts and kicking activities like soccer. Wikipedia articles on snapping hip mention that symptoms in the iliopsoas area, as opposed to the iliotibial band around the greater trochanter, are assosiated with problems with the hip joint itself. I guess gout can be the sole cause without any irreversible damage in the joint. In any case remember that there are legs blown off in Ukraine all the time; many babies in Africa don't get their hip dysplasia fixed and live a life void of prospects and full of pain, of which you've only had a small taste; there's more to life than sports and running etc.
Disclaimer: I'm not a medical expert. I read professional magazines now and then.
I have great hopes for the new generation of doctors. I was pleasantly surprised when one said something to the effect of: "You did not evolve to be that frail. Don't blame yourself." I find this a great improvement from the doctors of old who had to posit all kinds of weird theories just to avoid saying "we don't know". Stuff like the theory of retrograde menstruation as the cause for endometriosis, or genetic etiology for common conditions like obesity, literally adds insult to injury: You are the cause; it's something you did; it's something you <i>are</i>. It's all right to entertain different possibilities when you're doing research, but why bother patients with some unproven trivia that does not help in the least?
I claim that the best practice when encountering common ailments with unknown etiology is to tell the patient that the most probable ultimate cause for the condition is a germ of some sort (Cochran&Ewald). The next most probable cause is some other environmental factor, the patient himself is most likely faultless in this regard. It's truthful and kind of soothing too.
I would like to endorse that last item, that there is a potential harm that is not widely known. It's not specific to veganism, but the risk is elevated for them.
Oxalic acid is ubiquitous in plant-based foods. Absorbed oxalic acid can precipitate in the body as calcium oxalate. This most often damages the kidneys, but it can also cause joint pains and degeneration. The crystals are not as inflammatory as the crystals that cause gout, but they are much more persistent.
People who have trouble with fat absorption are at an increased risk for getting too much oxalic acid from their diet, a condition called enteric hyperoxaluria / oxalosis. These include persons treated for obesity with baryatric surgery or old fashioned weight loss drugs, and sufferers of IBD. This is a growing demographic. Their problems with kidneys and joints can very easily be imputed to pre-existing conditions like diabetes, overweight or autoimmune disorders.
The studies on oxalate content of foods are somewhat conflicting as to the precise amounts in each plant or foodstuff. It is not always clear what part is bound to e.g. calcium and how much is in a more readily absorbed form.
Legumes seem to contain significant amounts. Rhubarb is a well known source, but how many people know that a larger serving of carrots, sweet potatoes or almonds can be just as dangerous? Processing methods have a big effect: instant coffee has manyfold higher levels than ground and percolated coffee.
Oxalic acid also has some endogenous sources in the body, such as protein metabolism. It is a metabolite of both xylitol and ascorbic acid. Gut flora can both generate and consume oxalic acid, depending on the species.
I haven't found any oxalate data on novel highly processed plant based foods like meat and dairy substitutes. Fermentation might push it either way. Many of the ingredients, like mushrooms, almonds, spinach, beetroot and coconut seem to have very high levels of oxalate to begin with.
Perhaps you can now see why I'm worried. Add some supplement (or eating liver as suggested in other comments) that has too much vitamin A or D to the mix and you might also get a high blood calcium level and more crystallization in the body.
Oxalic acid is more famously the most common constituent of stones in the urinary tract. Kidney stones are often described as a "ten" on the pain scale from 1 to 10. It is not given that large stones will be the first symptom of too much oxalic acid, their formation might require low hydration or abnormalities in the pH of the urine. Smaller stones or crystals might imitate a urinary tract infection or a STD with painful discharge. There might be no urinary symptoms other than those resulting from kidney damage. Animal protein intake is a risk factor for renal and urinary tract calculi, so if vegans don't have a higher risk of stones it does not necessarily mean they are safe from other oxalate pathologies. But stones are definitely something to look for.
The standard way to prevent problems with dietary oxalic acid is to consume a small amount of calcium carbonate after meals to bind it in a non-soluble form. I would also recommend that people avoid xylitol and big doses of vitamins A, C and D.
If you are now concerned about it (you're welcome!), oxalate absorption and production can be assessed with a 24-hour urine collection sample. Note that the upper reference range might not be all that far from what is observed in primary (i.e. hereditary) hyperoxaluria, a very serious condition.
Most likely oxalic acid does not and will not have a big impact on the health of the vegan population. But is has some potential of being a major under-the-radar (persistent and low-grade inflammatory, crystal deposits perhaps hard to image) threat for serious and long-term problems like chronic kidney disease and osteoarthritis. Why do some people get these conditions early in life?
I hope this helps.
PS. I'm not a vegan, but I believe meat and dairy has had an immense negative impact on everyone's health, including vegans. There is of course the historic zoonotic origin of many high impact infectious diseases in domesticated animals. But I'm talking about a more modern development.
It used to be the case that the distribution and prevalence of gut microbiota was largely dependent on the fitness and mobility of the host. Nowadays the vast majority of mammal biomass is either livestock or humans. Their mobility and that of their manure is mainly supported by technology.
This independence of the host's fitness frees the microbiome to increase its own fitness in new, potentially pathogenic ways. One obvious modification could be to make the host eat more. Because the manure is spread by mechanized means, any increase in eaten and excreted volume results in a roughly proportionate advantage to the microbe. Animal breeding and market forces aren't strictly working against this development, perhaps the opposite.
This model of the etiology of obesity fits with the geographical prevalence: lower at high altitudes, i.e. upstream of agriculture. It would also explain why wild animals are getting fatter, if that is the case. It suggests the quick health fix of getting a fecal transplant from a healthy hunter-gatherer. The more remote and isolated the donor, the better. But we would have to be careful not to corrupt them as they get wealthy off their product.