I also consider the “paleo diet” somewhat silly, not because I think there’s a good reason for it not to be healthy, but because I think of it as impractical; how many of our modern fruits and vegetables, or even meats, closely resemble what we had available to eat more than 10kya? How many paleo practitioners will seriously evaluate making terrestrial arthropods a significant portion of their diet?
This seems to be rather an extreme case of making the perfect the enemy of the good. Sure there are differences between modern fruits, vegetables and meats and the pre-agricultural versions but they are a lot more similar to the pre-agricultural diet than grains or vegetable oils. Most paleo diet variants advocate trying to source foods that more closely match pre-agricultural staples—wild salmon, grass-fed beef, wild game, etc. - but I haven’t seen much direct evidence of the benefits of that approach (although you can make inferences based on other evidence).
Anyway, I think diet may be one of those things where there is a big risk of other optimizing and I think it is quite likely that there is no one size fits all diet that is suitable for everyone (due to different genetic heritages and tolerances for things like gluten, dairy, etc.). It’s an excellent place to apply some self-experimentation to see what works for you.
Paleo-type diets have worked well for me because they correspond closely to the kinds of foods I like to eat anyway and a major factor in the success of any diet is how ‘deprived’ you feel by the restrictions placed on what you can eat. YMMV but I think most people can probably benefit from eating fewer processed carbohydrates and sugar and more fruits and vegetables.
What’s the name of the bias of judging messages based on the messenger? I suspect part of my problem is that everyone I’ve personally met who advocated the paleo diet was also into homeopathy and crystal healing, and didn’t actually have any idea what paleolithic humans really ate.
The fact that we eat different things from our evolutionary ancestors should generate hypotheses about how dietary differences affect our health; two of the biggest changes to my mind would be a dramatic increase in starch consumption and an even larger increase in cooked versus raw food. However, I haven’t seen evidence that either of those is specifically a negative change, whereas increase in sugar consumption has been conclusively shown to be a big dietary evil.
One of the reasons I’m so active on this sub-thread is that dietary changes over the past two years have made huge differences in my day-to-day life, but I feel like I could still do better. However, I’m not eager to abandon cooking my food, to start eating mammals, or to stop eating all grains, so I want to hear convincing evidence to do those type of things before I’m willing to self-experiment with them. Your point that I should perhaps not try those anyway (because of feeling too restricted) is well taken.
What’s the name of the bias of judging messages based on the messenger?
I’m sure someone has discussed that here before .. the source heuristic? attribution/authority bias?
I suspect part of my problem is that everyone I’ve personally met who advocated the paleo diet was also into homeopathy and crystal healing, and didn’t actually have any idea what paleolithic humans really ate.
Interesting. Most of the new age types I have met are into vegetarianism.
I discovered the paleolithic diet in the late 90′s through this wonderful website devoted to it which I can no longer find. It presented a very convincing scientific case.
Humans evolved as opportunistic omnivores. Our bodies can run efficiently on a wide variety of diets. But nonetheless they are tuned to a certain range of conditions, and as you stray from that range random failures accumulate.
We changed suddenly in the shift to agriculture, and the archeological record shows that our bodies suffered—the move from meat rich paleolithic hunter-gatherer diets to neolithic agricultural diets is associated with a marked decrease in average height and overall ill-health. If I remember correctly, the average male european height was around 6′2″” 10k yrs ago, declined by half a foot in the neolithic age, and still has not fully recovered.
The evidence is also more specific. In every case where we have good specific evidence for biochemical problems in the diet, those problems are caused by dietary novelties. Examples: glycemic load, omega fatty acid profiles, potassium/sodium levels, nutrient load, etc—all of these are solved by the paleolithic diet.
So the real question is now that we have discovered all of these issues with the modern diet, how many other issues remain that we have yet to discover?
two of the biggest changes to my mind would be a dramatic increase in starch consumption and an even larger increase in cooked versus raw food. However, I haven’t seen evidence that either of those is specifically a negative change, whereas increase in sugar consumption has been conclusively shown to be a big dietary evil
Starch turns into sugar near immediately—your saliva can almost do the job itself, but the transformation completes quickly in the stomach. You should look at a piece of bread and instead see a mound of sugar. Actually, the bread is more sugarey than table sugar—it converts more quickly into pure glucose from what I recall.
Starch is the staple of the neolithic agricultural revolution. Cheap energy for the masses. It works, and typical humans as of today already have adapted significantly, but not nearly as much as we should. These cheap fuels lessen our lifespan. Some specific humans have not had nearly as much time to adapt—some native american tribes in particular—and they react in a spectacularly poor fashion on modern diets.
You also mention cooking, but this is not a new neolithic change. There is some debate, but general consensus is that cooking has been around for much longer than 10k yrs, and we have had more time to adapt to it. Nonetheless, overcooked food has specific problems—mainly carcinogens.
We changed suddenly in the shift to agriculture, and the archeological record shows that our bodies suffered—the move from meat rich paleolithic hunter-gatherer diets to neolithic agricultural diets is associated with a marked decrease in average height and overall ill-health. If I remember correctly, the average male european height was around 6′2″” 10k yrs ago, declined by half a foot in the neolithic age, and still has not fully recovered.
I’ve seen this claim many times from a bunch of people, but never accompanied by references to literature. Do you know what exact work it is based on, and how controversial it is in expert circles?
No. I was just recalling it from my memory, and my numbers are probably well off, but the effect seems to be widely acknowledged. It’s difficult to really determine a trend like this—naturally height and bone stature can vary widely from region to region.
some other data points from a paleo blog which show a less pronounced effect
what would be most illuminating would be to find an actual debate between paleontologists about this issue—that would probably have the highest density of info.
And on that note, other factors such as communicable diseases could also have played a role in decreasing average height and health of agriculturalists.
Be careful with things along the line of “the effect seems to be widely acknowledged”, just because those effects that are are also often the ones least critically reviewed. I have also read the 6′2″ height statistic, and never seen evidence that convinced me it was a reasonable average. I agree that a debate among paleontologists, especially one that completely omits mention of diet, disease or other explanatory causes, would be ideal to distill our best understanding of the facts. Then discussing diet, disease, etc. as possible explanations would move from facts to viable hypotheses.
Be careful with things along the line of “the effect seems to be widely acknowledged”, just because those effects that are are also often the ones least critically reviewed.
Yes this can be true, and it is worth digging into. The 6′2″” figure is just a number from memory. From what little searching I did recently, I can’t find much support for it.
The bone studies I have seen have a pretty wide dispersion of average heights. All show some trend for loss of average height around the dawn of agriculture (or even a little before), although it varies and is probably not as high as what I originally stated. This is probably so murky that it may not be worth drawing conclusions from.
A more interesting route could be to look at data from particular populations as they transition from hunter-gatherers to agriculturalists. There we could expect to see evidence for a significant loss of health initially followed by a massive selection effect, based on the health problems many humans from isolated tribes exhibit when exposed to the modern diet.
It just occurred to me that size is one of the easiest things to select for (which is why large dogs are an order of magnitude larger than small dogs), and agriculturists are in much less need of size than hunter gatherers. Maybe humans pre-agriculture were all naturally taller, but rarely reached their maximum height?
I believe that people living in developed nations usually grow to their maximum individual height, and that differences in height are almost entirely genetic among people with adequate nutrition. Since we’ve gotten taller as malnutrition has become less and less frequent, it seems reasonable to postulate that this is fulfilling potential rather than genetic drift. However, famines during the beginning of the agricultural revolution could have decreased the height of humans, since being larger didn’t help one find alternate food sources (like it might have earlier in human history), but did require more sustenance.
There are probably a number of holes in this theory; despite humans breeding dogs to be vastly varying in size during this same period, I doubt that the time period in question is really quite enough to have altered human size naturally. I also think archeologists would be aware of this and be able to recognize changes even in malnourished size over the time periods being discussed.
Most of the new age types I have met are into vegetarianism.
You’re not wrong...the paleo types that I’ve met are pretty crazy. I was hanging out with three of them a few months back (naked in a hot tub, ’natch), and all three considered themselves to be on the paleo diet, but also were raw-food only vegans, which I consider nuts, but corroborates your point about new-agers. Another that I met sometime earlier wasn’t vegetarian, but was nearly as crazy as the other three.
all of these are solved by the paleolithic diet
I agree that they would be if the diet was carefully followed, but I wonder about how well people practicing the paleolithic diet actually approximate it. My biggest wonder is whether people work hard enough to eat only wild and grass-fed meats, which is necessary to balance out the omega fatty acid profile; otherwise meat is still bad for that. Nutrient load is also of interest to me, just because over the last several thousand years we’ve genetically engineered a lot of the nutrients out of our foods, though I suspect we haven’t gone far enough for that to be a real concern.
I am also not convinced that our ancestors ate as much meat as is often claimed; present-day tribes certainly don’t eat that much, even the most aggressive hunters, and many tribes subsist mostly on grubs and bugs for their protein. I’m not at all confident that too much meat is a problem in our diet, but I feel like the paleo diet is often a convenient excuse for people who want to eat a lot of meat, which is the same way I feel about Atkins. That doesn’t speak to the actual worth of the diet, but it’s worth keeping in mind as a potentially biasing factor.
bread is more sugarey than table sugar
Please stop repeating this popular myth. Glucose is a sugar, and starch is glucose, but that’s very misleading. Glucose is naturally handled really well by the body, but fructose (and by extension, sucrose) is not. Sugar: The Bitter Truth is long but informative, although it has its detractors as well. However, both sources agree that glucose is just fine for you, while I don’t think anybody (except lobbies, perhaps) seriously claims that table sugar isn’t harmful.
I realize that cooked food has been around for a long time, but probably not long enough to induce significant evolutionary adaptations. What’s really interesting to me is that animals—all primates, my dog, etc—prefer cooked food to uncooked, even if it’s not a natural part of their diet.
I agree that they would be if the diet was carefully followed, but I wonder about how well people practicing the paleolithic diet actually approximate it.
Yes of course this is true, it can be difficult to follow. I believe in it in theory, but in practice is a whole other matter.
My biggest wonder is whether people work hard enough to eat only wild and grass-fed meats, which is necessary to balance out the omega fatty acid profile; otherwise meat is still bad for that.
Yes, although vegetable oils and fried foods can be just as bad. I take fish oil supplements to help at least.
bread is more sugarey than table sugar
Please stop repeating this popular myth. Glucose is a sugar, and starch is glucose, but that’s very misleading.
I meant ‘sugarey’ in terms of the principle pure metabolic form of sugar, which is glucose. This is not a myth—starch converts so easily into glucose that you should think of it as glucose. Glucose is pure true sugar as far as your body is concerned. Thus starch is more pure ‘sugarey’ than table sugar. Ask a diabetic about the insulin response of starch.
You are discussing additional reasons why fructose is potentially even worse than starch/glucose.
Large glucose spikes are not “just fine for you” in the long term. There is significant mounting evidence that these large insulin spikes are a novel feature of our diet that we have not had adequate time to fully adapt for. In the long term it contributes to weight gain and the metabolic syndrome set of diseases.
Naturally we have varying degrees of genetic resistance, but a reduced insulin load is just plain healthier for everyone. This is no myth.
A key feature of the paleo-diet is low overall caloric density, low glucose, and low insulin load.
I realize that cooked food has been around for a long time, but probably not long enough to induce significant evolutionary adaptations.
I dont know about this. Some humans have significant evolutionary adaptations for grains and milk already. Cooking has been around for much longer, and we can expect significant adaptations for that. Indeed, if anything we have probably lost much of the robustness of our gut defenses as a result, but gained adaptations against potential ill-effects of cooking (carcinogens?)
Glucose does not evoke a metabolic response identical to fructose. Perhaps most importantly, glucose can be metabolized by all cells in the body, but fructose specifically stresses the liver. Quantitatively, fructose also causes much higher triglyceride and aldehyde production than an equivalent amount of glucose, and participates in glycogenesis much less efficiently; since glycogenesis is the strongest negative-feedback mechanism for dealing with excessive insulin, this ought to be a significant difference.
This is not to say that insulin spikes or high blood-glucose levels are healthful, but they can be regulated without eliminating carbohydrates from our diets. “Glucose is pure true sugar” as far as chemists are concerned, perhaps, but our body treats different sugars quite differently, and it is dangerous to conflate them.
I never disagreed with your point that fructose is worse than glucose. I haven’t investigated it much, but I find it reasonable. I was merely pointing out that starch converts to mass glucose and mass glucose itself is not healthy. Not healthy at all.
Insulin spikes is one issue, but total insulin load itself is another. In theory you can control insulin spikes by eating a large number of smaller snacks, but in practice this is difficult for a variety of reasons—including not having any direct control over the rate of one’s stomach emptying. As a diabetic could tell you (my brother is type 1), minimizing starch is crucial for reducing total insulin load.
We think of aging as measured by the passage of time, but the body does not measure time according to atomic clocks or rotations of the earth. Time in the body is measured in terms of biological processes.
Your heart’s age is not measured in terms of seconds or minutes but in beats.
Your skin’s age is measured largely in number of sun exposures and total sheddings.
In general the aging of most systems in the body can be measured in number of cellular reproductions and major metabolic cycles.
We know that general lifespan is measured more in total calories than absolute time. Total insulin response is perhaps an even more accurate measure, and at the very least it measures the differential aging of the metabolism of sugar regulation and energy storage in particular.
Reducing or eliminating starch is up there as one of the more important health improvements one can make. It helps reduce total calorie load, shift to a more ideal weight, and places less strain on your pancreas. High fiber carbohydrates are a different manner—but mostly what people mean by carbohydrates is typically starch.
We know that general lifespan is measured more in total calories than absolute time
So staying sedentary, while not overeating, should result in about a two-fold life-expectancy increase over an athlete that consumes about twice as many calories daily? Abstractly, that makes sense, but empirically we know that the truth is close to the opposite.
From what i remember about caloric restriction research, current empirical data does support the abstract theory, but I did not mean to imply some exact linear relation. From what I remember, exercise has health benefits but nothing near the scale of longevity increase you get from caloric restriction.
My impression is that caloric restriction has a threshold effect—there’s a mechanism that gets invoked when the calories are low enough, though it isn’t a sharp boundary. Is this at all accurate?
This matches what I’ve read—that the body switches into different metabolic modes based on caloric abundance. Entire patterns of gene expression change.
Today we spend almost all of our time in the caloric-abundance high burn mode, and this accelerates metabolic aging.
However, I’m also thinking that caloric burn accelerates some aging processes by itself, but it is quite difficult to dissociate that from everything else—insulin, gene expression, etc etc
Person A = sedentary 60 kg female, eats 1500 kcal/day (which is not calorie restriction, but fairly reasonable for that body weight and activity level)
Person B = 60 kg female marathoner, eats 3000 kcal/day (high, but certainly possible)
Let’s further assume that their diets are compositionally the same, so that B eats the same things as A in the same quantities, just twice as often.
Life expectancy difference? My money is on B to live longer. Yours?
some quick google searching on “athlete lifespan” looks to support my bet:
from this site concerning elite athletes more likely to fit that 2x caloric profile:
What is the life expectancy of world class athletes?
Not so good. The average elite athlete will die by the age of 67. That is considerably lower then the 76 year life expectancy of the average American. Do you want to hear something that is really scary? According to the NFL Players Association, the average life expectancy of an NFL player is 58 years of age.
I can’t really think of a study that would isolate for all the factors, but overall from what i’ve seen exercise is only healthy in moderate amounts, and taken to athletic levels the benefit is overshadowed by the higher caloric entropy.
Remember that heat is chaos, and we measure car lifetimes partly in mileage—so total entropy is a reasonable measure.
I suspect that a lot of the difference is accounted for by injuries, both major and minor. Football players, in particular, take a whole lot of abuse. A regular person exercising carefully at the gym won’t have that problem.
Perhaps, but death from such injuries is extremely rare. I doubt it is any significant contributor to their death rate.
Burning off the calories through exercise is certainly more healthy than getting fat, but from what i’ve seen caloric intake is negatively correlated with lifespan in general.
That’s a good point and could explain why footballers have a lifespan 5 years or so lower than high end athletes and much lower than the general population.
It would be interesting to compare boxers/fighters based on weight class. They take alot of head beating and you can compare for different caloric intakes.
Sumo wrestlers would be another interesting data point—very high caloric intake and no concussions.
I suspect that one would find a significant caloric effect independent of concussions. Most footballers are quite big and have very high caloric intakes.
I’d expect QB’s to live longer than typical linemen.
I cheated a little by mentioning that person B was a runner; I’ve seen those statistics, and they mysteriously don’t apply to runners. Likewise, footballers (both gridiron and the real kind) have very high rates of arthritis, but runners do not. It seems to be a difference between what we were evolved to do and what we can do. Analogous to this discussion? Very likely :-)
One not-so-mysterious difference is muscle mass; long-distance runners don’t develop much, whereas many other athletes do. Muscle is even harder to pump blood through than fat, so an extra 20kg of muscle is harder on the heart than 20kg of fat, which is sometimes cited as the reason that body builders so often have serious cardiac health problems (other reasons include large amounts of protein and cholesterol consumed, but I suspect you don’t buy those explanations).
EDIT: I shouldn’t stress my claim so much. I posted quickly because I’m busy with other things, but post-posting Googling seems to disagree with what I said; I haven’t actually found anything I trust yet, but it does seem that moving from long-distance running to ultra-long-distance running may move athletes back into a risk category.
As a diabetic could tell you (my brother is type 1), minimizing starch is crucial for reducing total insulin load.
Wait, what? As a diabetic I avoid starch (somewhat) to reduce blood glucose variability, but I’d never heard of “insulin load”, and searching PubMed and Google for that phrase didn’t turn up anything interesting. Starch only causes blood glucose variability if it’s digested too quickly, as measured by glycemic index, which happens with things like breadcrumbs but not with things like bread. My understanding of the issue is that insulin matters only insofar as it interacts with blood glucose, glucagon and liver storage. If insulin had any direct bad effects, I would consider this surprising, and a big deal.
By insulin load i just mean total insulin. You diabetics know exactly how much you use in a given day, but regular people produce similar amounts automatically. The idea is that in the modern diet we consume too many calories mainly from energy dense foods such as carbohydrates which cause more insulin spikes and overwork the pancreas, eventually leading to destabilization and metabolic syndrome (type 2 diabetes and associated diseases). We haven’t had enough time to optimize for these conditions.
There’s also some recent evidence / claims that cooking (and meat eating) were in part responsible for the big jump in human brain size and intelligence.
That is interesting. I was aware that cooking opened up a whole new world of plant foods to us—most of our neolithic vegetable staples are indegistable or even poisonous until cooked. I was not aware that cooking significantly increases meat digestability. Although raw meats still seem much more digestable than raw neolithic staples. You can’t eat raw grains or potatoes, for example.
Regardless of what other selection pressures may have been driving us towards larger brains, it’s clear that hunting and cooking provided the resource advantage to support the quick increase. I imagine that the growth in complexity of language, culture and technology drove the selection effect.
It’s interesting though that our hominid brains rapidly expanded up to about 100-200 billion neurons (the latter only in our larger brained neandrathal cousins) and then stopped. This is about the same upper neuron count we see in elephants and cetaceans.
all three considered themselves to be on the paleo diet, but also were raw-food only vegans
Raw-food veganism and paleo type diets are pretty hard to reconcile (though probably less so than regular vegan diets and paleo type diets). There are raw food animal diets but they are quite distinct from raw food veganism and are more similar to standard paleo type diets.
My biggest wonder is whether people work hard enough to eat only wild and grass-fed meats
This is probably the most difficult aspect of the diet to follow strictly due to the relative difficulty and expense of obtaining these types of meat and fish. That’s why most of paleo type diets recommend Omega 3 supplementation and things like Omega 3 enriched eggs.
I feel like the paleo diet is often a convenient excuse for people who want to eat a lot of meat
This sounds to me like being stuck in the mindset that a diet has to be about deprivation or eating foods you don’t particularly enjoy. There’s no reason that healthy foods can’t also be foods you like to eat. As a rule it seems that foods we are evolutionarily adapted to eat are both tasty and nutritious. It’s the ‘super-stimuli’ of refined carbs, refined sugar and processed foods which tend to fit the stereotype of ‘if it tastes good it must be bad for you’.
Glucose is naturally handled really well by the body, but fructose (and by extension, sucrose) is not.
Fructose and sucrose appear to be worse than glucose but it is false to say that glucose is naturally handled really well by the body, at least in the quantities produced by a typical western diet. Much of the harm associated with sugar and refined carbohydrate consumption appears to come from the over-stimulation of the insulin response and resulting blood sugar spikes and crashes caused by eating refined carbs and sugars. Bread is not ‘more sugary’ than table sugar but white bread does have a Glycemic Index that rivals table sugar.
Glucose is an important cellular fuel source and a key component of human metabolism but we are simply not well adapted to deal with the onslaught of glucose produced by consuming grains and refined sugars.
When I said that I considered a raw-food vegan paleo diet nuts, that’s what I meant, that they just seem to difficult to reconcile.
This sounds to me like being stuck in the mindset that a diet has to be about deprivation or eating foods you don’t particularly enjoy.
My statement wasn’t an argument against meat; it was cautionary, and an appropriate response is to point out that I really like eating rice and beans, and should be equally cautious about arguing for their health benefits because of the stake I have in wanting those to be healthful.
My point about bread was that a 4oz piece of bread is not as unhealthy as a 4oz piece of hard candy. I don’t consider refined carbohydrates, or even unrefined but purer carbohydrates (such as potatoes) healthful. I’m having a lot of trouble finding good sources to either back me up or discredit what I’m trying to say (the video linked to earlier is one of the former), but the impression that I’m under is that starch doesn’t cause harmful insulin responses or large insulin spikes if eaten in the much less pure forms; that is, even significant quantities of carbohydrates are digested slowly enough to not cause problems if they are molecularly dispersed among protein, fats, or most especially fiber, and that this is a super-linear effect, more than would be explained simply by eating less of a pure carbohydrate.
but the impression that I’m under is that starch doesn’t cause harmful insulin responses or large insulin spikes if eaten in the much less pure forms; that is, even significant quantities of carbohydrates are digested slowly enough to not cause problems if they are molecularly dispersed among protein, fats, or most especially fiber
I’m not too sure on what differences there are between starch and carbohydrates more generally but I believe it is true that insulin response is lower when carbohydrates are consumed in the form of foods with other components. This is the basic reasoning behind getting your carbs in the form of fruits and vegetables (which also provide plentiful fiber) rather than grains and tubers in paleo type diets. I’ve even seen it claimed that you are better off ordering fries rather than baked potato because the fat slows the rate of absorption but I don’t know how well sourced that is.
Potatoes (not baked), bananas, wild rice and other similar medium GI foods are generally viewed as ok in small quantities by the paleo diet resources I’ve read. They still provoke significantly greater glucose response than things like green vegetables, fruits and berries however while having less overall nutritional value and not significantly greater fiber content.
I bet french fries could be better than a baked potato, but for that to be the case I think they would have to be unsalted (though the potassium in potatoes partially counteracts the salt) and fried in more healthful oils (probably saturated, since heat + unsaturated oil → trans fats). This sounds like an experiment worth performing on myself; I like making french fries, and I could see how satiated I feel after a similar calorie-worth of french fries versus baked potato, and how I feel an hour later (more or less sluggish). I don’t eat much potato in any form, but answering that question (at least with regard to myself) might be a worthy enterprise.
I personally think bananas are great, but it seems like they don’t fit into the paleo scheme because they are so dramatically different than anything that existed in our ancestral environment. Wild potatoes are too toxic for humans to eat, even cooked IIRC.
I’ve also heard a plausible theory that a lot of the soil that food is grown on is mineral-depleted. Manure isn’t going to solve the problem if it’s from animals which have been fed food grown on mineral-depleted soil.
And I’ve wondered whether there are any important nutrients in insects.
What’s the name of the bias of judging messages based on the messenger? I suspect part of my problem is that everyone I’ve personally met who advocated the paleo diet was also into homeopathy and crystal healing, and didn’t actually have any idea what paleolithic humans really ate.
I’m not sure what the name of the bias is but I’d have probably had the same reaction as you if I’d seen the paleo diet associated with homeopathy or crystal healing. My impression is that it is over-represented in the contrarian cluster that is over-represented on LessWrong (atheist, libertarian, software engineer, not given to an interest in homeopathy or crystal healing) but that might just be some kind of selection bias on my part. I tend to associate raw-food / vegan eating with the nutty new-age fringe and have the same kind of negative associations with those diets as you describe for that reason.
I would imagine you could get pretty close to a paleo type diet without stopping cooking your food or eating mammals if you are ok with eating fish / seafood, eggs and cheese / dairy. It’s pretty difficult to do it without cutting out grains however. I didn’t find that too difficult (well, except beer) because I could always take or leave bread / rice / pasta anyway but I’ve heard from people who really enjoyed those foods that after a (sometimes difficult) period of adjustment they adapted to a grain free diet quite well.
This seems to be rather an extreme case of making the perfect the enemy of the good. Sure there are differences between modern fruits, vegetables and meats and the pre-agricultural versions but they are a lot more similar to the pre-agricultural diet than grains or vegetable oils. Most paleo diet variants advocate trying to source foods that more closely match pre-agricultural staples—wild salmon, grass-fed beef, wild game, etc. - but I haven’t seen much direct evidence of the benefits of that approach (although you can make inferences based on other evidence).
Anyway, I think diet may be one of those things where there is a big risk of other optimizing and I think it is quite likely that there is no one size fits all diet that is suitable for everyone (due to different genetic heritages and tolerances for things like gluten, dairy, etc.). It’s an excellent place to apply some self-experimentation to see what works for you.
Paleo-type diets have worked well for me because they correspond closely to the kinds of foods I like to eat anyway and a major factor in the success of any diet is how ‘deprived’ you feel by the restrictions placed on what you can eat. YMMV but I think most people can probably benefit from eating fewer processed carbohydrates and sugar and more fruits and vegetables.
What’s the name of the bias of judging messages based on the messenger? I suspect part of my problem is that everyone I’ve personally met who advocated the paleo diet was also into homeopathy and crystal healing, and didn’t actually have any idea what paleolithic humans really ate.
The fact that we eat different things from our evolutionary ancestors should generate hypotheses about how dietary differences affect our health; two of the biggest changes to my mind would be a dramatic increase in starch consumption and an even larger increase in cooked versus raw food. However, I haven’t seen evidence that either of those is specifically a negative change, whereas increase in sugar consumption has been conclusively shown to be a big dietary evil.
One of the reasons I’m so active on this sub-thread is that dietary changes over the past two years have made huge differences in my day-to-day life, but I feel like I could still do better. However, I’m not eager to abandon cooking my food, to start eating mammals, or to stop eating all grains, so I want to hear convincing evidence to do those type of things before I’m willing to self-experiment with them. Your point that I should perhaps not try those anyway (because of feeling too restricted) is well taken.
I’m sure someone has discussed that here before .. the source heuristic? attribution/authority bias?
Interesting. Most of the new age types I have met are into vegetarianism.
I discovered the paleolithic diet in the late 90′s through this wonderful website devoted to it which I can no longer find. It presented a very convincing scientific case.
Humans evolved as opportunistic omnivores. Our bodies can run efficiently on a wide variety of diets. But nonetheless they are tuned to a certain range of conditions, and as you stray from that range random failures accumulate.
We changed suddenly in the shift to agriculture, and the archeological record shows that our bodies suffered—the move from meat rich paleolithic hunter-gatherer diets to neolithic agricultural diets is associated with a marked decrease in average height and overall ill-health. If I remember correctly, the average male european height was around 6′2″” 10k yrs ago, declined by half a foot in the neolithic age, and still has not fully recovered.
The evidence is also more specific. In every case where we have good specific evidence for biochemical problems in the diet, those problems are caused by dietary novelties. Examples: glycemic load, omega fatty acid profiles, potassium/sodium levels, nutrient load, etc—all of these are solved by the paleolithic diet.
So the real question is now that we have discovered all of these issues with the modern diet, how many other issues remain that we have yet to discover?
Starch turns into sugar near immediately—your saliva can almost do the job itself, but the transformation completes quickly in the stomach. You should look at a piece of bread and instead see a mound of sugar. Actually, the bread is more sugarey than table sugar—it converts more quickly into pure glucose from what I recall.
Starch is the staple of the neolithic agricultural revolution. Cheap energy for the masses. It works, and typical humans as of today already have adapted significantly, but not nearly as much as we should. These cheap fuels lessen our lifespan. Some specific humans have not had nearly as much time to adapt—some native american tribes in particular—and they react in a spectacularly poor fashion on modern diets.
You also mention cooking, but this is not a new neolithic change. There is some debate, but general consensus is that cooking has been around for much longer than 10k yrs, and we have had more time to adapt to it. Nonetheless, overcooked food has specific problems—mainly carcinogens.
jacob_cannell:
I’ve seen this claim many times from a bunch of people, but never accompanied by references to literature. Do you know what exact work it is based on, and how controversial it is in expert circles?
No. I was just recalling it from my memory, and my numbers are probably well off, but the effect seems to be widely acknowledged. It’s difficult to really determine a trend like this—naturally height and bone stature can vary widely from region to region.
One summary here
some other data points from a paleo blog which show a less pronounced effect
what would be most illuminating would be to find an actual debate between paleontologists about this issue—that would probably have the highest density of info.
And on that note, other factors such as communicable diseases could also have played a role in decreasing average height and health of agriculturalists.
Be careful with things along the line of “the effect seems to be widely acknowledged”, just because those effects that are are also often the ones least critically reviewed. I have also read the 6′2″ height statistic, and never seen evidence that convinced me it was a reasonable average. I agree that a debate among paleontologists, especially one that completely omits mention of diet, disease or other explanatory causes, would be ideal to distill our best understanding of the facts. Then discussing diet, disease, etc. as possible explanations would move from facts to viable hypotheses.
Yes this can be true, and it is worth digging into. The 6′2″” figure is just a number from memory. From what little searching I did recently, I can’t find much support for it.
The bone studies I have seen have a pretty wide dispersion of average heights. All show some trend for loss of average height around the dawn of agriculture (or even a little before), although it varies and is probably not as high as what I originally stated. This is probably so murky that it may not be worth drawing conclusions from.
A more interesting route could be to look at data from particular populations as they transition from hunter-gatherers to agriculturalists. There we could expect to see evidence for a significant loss of health initially followed by a massive selection effect, based on the health problems many humans from isolated tribes exhibit when exposed to the modern diet.
It just occurred to me that size is one of the easiest things to select for (which is why large dogs are an order of magnitude larger than small dogs), and agriculturists are in much less need of size than hunter gatherers. Maybe humans pre-agriculture were all naturally taller, but rarely reached their maximum height?
I believe that people living in developed nations usually grow to their maximum individual height, and that differences in height are almost entirely genetic among people with adequate nutrition. Since we’ve gotten taller as malnutrition has become less and less frequent, it seems reasonable to postulate that this is fulfilling potential rather than genetic drift. However, famines during the beginning of the agricultural revolution could have decreased the height of humans, since being larger didn’t help one find alternate food sources (like it might have earlier in human history), but did require more sustenance.
There are probably a number of holes in this theory; despite humans breeding dogs to be vastly varying in size during this same period, I doubt that the time period in question is really quite enough to have altered human size naturally. I also think archeologists would be aware of this and be able to recognize changes even in malnourished size over the time periods being discussed.
You’re not wrong...the paleo types that I’ve met are pretty crazy. I was hanging out with three of them a few months back (naked in a hot tub, ’natch), and all three considered themselves to be on the paleo diet, but also were raw-food only vegans, which I consider nuts, but corroborates your point about new-agers. Another that I met sometime earlier wasn’t vegetarian, but was nearly as crazy as the other three.
I agree that they would be if the diet was carefully followed, but I wonder about how well people practicing the paleolithic diet actually approximate it. My biggest wonder is whether people work hard enough to eat only wild and grass-fed meats, which is necessary to balance out the omega fatty acid profile; otherwise meat is still bad for that. Nutrient load is also of interest to me, just because over the last several thousand years we’ve genetically engineered a lot of the nutrients out of our foods, though I suspect we haven’t gone far enough for that to be a real concern.
I am also not convinced that our ancestors ate as much meat as is often claimed; present-day tribes certainly don’t eat that much, even the most aggressive hunters, and many tribes subsist mostly on grubs and bugs for their protein. I’m not at all confident that too much meat is a problem in our diet, but I feel like the paleo diet is often a convenient excuse for people who want to eat a lot of meat, which is the same way I feel about Atkins. That doesn’t speak to the actual worth of the diet, but it’s worth keeping in mind as a potentially biasing factor.
Please stop repeating this popular myth. Glucose is a sugar, and starch is glucose, but that’s very misleading. Glucose is naturally handled really well by the body, but fructose (and by extension, sucrose) is not. Sugar: The Bitter Truth is long but informative, although it has its detractors as well. However, both sources agree that glucose is just fine for you, while I don’t think anybody (except lobbies, perhaps) seriously claims that table sugar isn’t harmful.
I realize that cooked food has been around for a long time, but probably not long enough to induce significant evolutionary adaptations. What’s really interesting to me is that animals—all primates, my dog, etc—prefer cooked food to uncooked, even if it’s not a natural part of their diet.
Yes of course this is true, it can be difficult to follow. I believe in it in theory, but in practice is a whole other matter.
Yes, although vegetable oils and fried foods can be just as bad. I take fish oil supplements to help at least.
I meant ‘sugarey’ in terms of the principle pure metabolic form of sugar, which is glucose. This is not a myth—starch converts so easily into glucose that you should think of it as glucose. Glucose is pure true sugar as far as your body is concerned. Thus starch is more pure ‘sugarey’ than table sugar. Ask a diabetic about the insulin response of starch.
You are discussing additional reasons why fructose is potentially even worse than starch/glucose.
Large glucose spikes are not “just fine for you” in the long term. There is significant mounting evidence that these large insulin spikes are a novel feature of our diet that we have not had adequate time to fully adapt for. In the long term it contributes to weight gain and the metabolic syndrome set of diseases.
Naturally we have varying degrees of genetic resistance, but a reduced insulin load is just plain healthier for everyone. This is no myth.
A key feature of the paleo-diet is low overall caloric density, low glucose, and low insulin load.
I dont know about this. Some humans have significant evolutionary adaptations for grains and milk already. Cooking has been around for much longer, and we can expect significant adaptations for that. Indeed, if anything we have probably lost much of the robustness of our gut defenses as a result, but gained adaptations against potential ill-effects of cooking (carcinogens?)
Glucose does not evoke a metabolic response identical to fructose. Perhaps most importantly, glucose can be metabolized by all cells in the body, but fructose specifically stresses the liver. Quantitatively, fructose also causes much higher triglyceride and aldehyde production than an equivalent amount of glucose, and participates in glycogenesis much less efficiently; since glycogenesis is the strongest negative-feedback mechanism for dealing with excessive insulin, this ought to be a significant difference.
This is not to say that insulin spikes or high blood-glucose levels are healthful, but they can be regulated without eliminating carbohydrates from our diets. “Glucose is pure true sugar” as far as chemists are concerned, perhaps, but our body treats different sugars quite differently, and it is dangerous to conflate them.
I never disagreed with your point that fructose is worse than glucose. I haven’t investigated it much, but I find it reasonable. I was merely pointing out that starch converts to mass glucose and mass glucose itself is not healthy. Not healthy at all.
Insulin spikes is one issue, but total insulin load itself is another. In theory you can control insulin spikes by eating a large number of smaller snacks, but in practice this is difficult for a variety of reasons—including not having any direct control over the rate of one’s stomach emptying. As a diabetic could tell you (my brother is type 1), minimizing starch is crucial for reducing total insulin load.
We think of aging as measured by the passage of time, but the body does not measure time according to atomic clocks or rotations of the earth. Time in the body is measured in terms of biological processes.
Your heart’s age is not measured in terms of seconds or minutes but in beats.
Your skin’s age is measured largely in number of sun exposures and total sheddings.
In general the aging of most systems in the body can be measured in number of cellular reproductions and major metabolic cycles.
We know that general lifespan is measured more in total calories than absolute time. Total insulin response is perhaps an even more accurate measure, and at the very least it measures the differential aging of the metabolism of sugar regulation and energy storage in particular.
Reducing or eliminating starch is up there as one of the more important health improvements one can make. It helps reduce total calorie load, shift to a more ideal weight, and places less strain on your pancreas. High fiber carbohydrates are a different manner—but mostly what people mean by carbohydrates is typically starch.
So staying sedentary, while not overeating, should result in about a two-fold life-expectancy increase over an athlete that consumes about twice as many calories daily? Abstractly, that makes sense, but empirically we know that the truth is close to the opposite.
From what i remember about caloric restriction research, current empirical data does support the abstract theory, but I did not mean to imply some exact linear relation. From what I remember, exercise has health benefits but nothing near the scale of longevity increase you get from caloric restriction.
My impression is that caloric restriction has a threshold effect—there’s a mechanism that gets invoked when the calories are low enough, though it isn’t a sharp boundary. Is this at all accurate?
This matches what I’ve read—that the body switches into different metabolic modes based on caloric abundance. Entire patterns of gene expression change.
Today we spend almost all of our time in the caloric-abundance high burn mode, and this accelerates metabolic aging.
However, I’m also thinking that caloric burn accelerates some aging processes by itself, but it is quite difficult to dissociate that from everything else—insulin, gene expression, etc etc
Would you accept a sub-linear correlation?
Person A = sedentary 60 kg female, eats 1500 kcal/day (which is not calorie restriction, but fairly reasonable for that body weight and activity level)
Person B = 60 kg female marathoner, eats 3000 kcal/day (high, but certainly possible)
Let’s further assume that their diets are compositionally the same, so that B eats the same things as A in the same quantities, just twice as often.
Life expectancy difference? My money is on B to live longer. Yours?
some quick google searching on “athlete lifespan” looks to support my bet:
from this site concerning elite athletes more likely to fit that 2x caloric profile:
similar results for athletes in general
I can’t really think of a study that would isolate for all the factors, but overall from what i’ve seen exercise is only healthy in moderate amounts, and taken to athletic levels the benefit is overshadowed by the higher caloric entropy.
Remember that heat is chaos, and we measure car lifetimes partly in mileage—so total entropy is a reasonable measure.
I suspect that a lot of the difference is accounted for by injuries, both major and minor. Football players, in particular, take a whole lot of abuse. A regular person exercising carefully at the gym won’t have that problem.
Perhaps, but death from such injuries is extremely rare. I doubt it is any significant contributor to their death rate.
Burning off the calories through exercise is certainly more healthy than getting fat, but from what i’ve seen caloric intake is negatively correlated with lifespan in general.
With footballers, there’s reason to think it’s accumulated concussions rather than death from a single injury.
That’s a good point and could explain why footballers have a lifespan 5 years or so lower than high end athletes and much lower than the general population.
It would be interesting to compare boxers/fighters based on weight class. They take alot of head beating and you can compare for different caloric intakes.
Sumo wrestlers would be another interesting data point—very high caloric intake and no concussions.
I suspect that one would find a significant caloric effect independent of concussions. Most footballers are quite big and have very high caloric intakes.
I’d expect QB’s to live longer than typical linemen.
I cheated a little by mentioning that person B was a runner; I’ve seen those statistics, and they mysteriously don’t apply to runners. Likewise, footballers (both gridiron and the real kind) have very high rates of arthritis, but runners do not. It seems to be a difference between what we were evolved to do and what we can do. Analogous to this discussion? Very likely :-)
One not-so-mysterious difference is muscle mass; long-distance runners don’t develop much, whereas many other athletes do. Muscle is even harder to pump blood through than fat, so an extra 20kg of muscle is harder on the heart than 20kg of fat, which is sometimes cited as the reason that body builders so often have serious cardiac health problems (other reasons include large amounts of protein and cholesterol consumed, but I suspect you don’t buy those explanations).
EDIT: I shouldn’t stress my claim so much. I posted quickly because I’m busy with other things, but post-posting Googling seems to disagree with what I said; I haven’t actually found anything I trust yet, but it does seem that moving from long-distance running to ultra-long-distance running may move athletes back into a risk category.
All else being equal and assuming A gets some exercise and is not fully sedentary, yes I’d bet on A.
Of course, the highest lifespan would be for caloric intake well below today’s average.
Wait, what? As a diabetic I avoid starch (somewhat) to reduce blood glucose variability, but I’d never heard of “insulin load”, and searching PubMed and Google for that phrase didn’t turn up anything interesting. Starch only causes blood glucose variability if it’s digested too quickly, as measured by glycemic index, which happens with things like breadcrumbs but not with things like bread. My understanding of the issue is that insulin matters only insofar as it interacts with blood glucose, glucagon and liver storage. If insulin had any direct bad effects, I would consider this surprising, and a big deal.
By insulin load i just mean total insulin. You diabetics know exactly how much you use in a given day, but regular people produce similar amounts automatically. The idea is that in the modern diet we consume too many calories mainly from energy dense foods such as carbohydrates which cause more insulin spikes and overwork the pancreas, eventually leading to destabilization and metabolic syndrome (type 2 diabetes and associated diseases). We haven’t had enough time to optimize for these conditions.
There’s also some recent evidence / claims that cooking (and meat eating) were in part responsible for the big jump in human brain size and intelligence.
That is interesting. I was aware that cooking opened up a whole new world of plant foods to us—most of our neolithic vegetable staples are indegistable or even poisonous until cooked. I was not aware that cooking significantly increases meat digestability. Although raw meats still seem much more digestable than raw neolithic staples. You can’t eat raw grains or potatoes, for example.
Regardless of what other selection pressures may have been driving us towards larger brains, it’s clear that hunting and cooking provided the resource advantage to support the quick increase. I imagine that the growth in complexity of language, culture and technology drove the selection effect.
It’s interesting though that our hominid brains rapidly expanded up to about 100-200 billion neurons (the latter only in our larger brained neandrathal cousins) and then stopped. This is about the same upper neuron count we see in elephants and cetaceans.
Raw-food veganism and paleo type diets are pretty hard to reconcile (though probably less so than regular vegan diets and paleo type diets). There are raw food animal diets but they are quite distinct from raw food veganism and are more similar to standard paleo type diets.
This is probably the most difficult aspect of the diet to follow strictly due to the relative difficulty and expense of obtaining these types of meat and fish. That’s why most of paleo type diets recommend Omega 3 supplementation and things like Omega 3 enriched eggs.
This sounds to me like being stuck in the mindset that a diet has to be about deprivation or eating foods you don’t particularly enjoy. There’s no reason that healthy foods can’t also be foods you like to eat. As a rule it seems that foods we are evolutionarily adapted to eat are both tasty and nutritious. It’s the ‘super-stimuli’ of refined carbs, refined sugar and processed foods which tend to fit the stereotype of ‘if it tastes good it must be bad for you’.
Fructose and sucrose appear to be worse than glucose but it is false to say that glucose is naturally handled really well by the body, at least in the quantities produced by a typical western diet. Much of the harm associated with sugar and refined carbohydrate consumption appears to come from the over-stimulation of the insulin response and resulting blood sugar spikes and crashes caused by eating refined carbs and sugars. Bread is not ‘more sugary’ than table sugar but white bread does have a Glycemic Index that rivals table sugar.
Glucose is an important cellular fuel source and a key component of human metabolism but we are simply not well adapted to deal with the onslaught of glucose produced by consuming grains and refined sugars.
When I said that I considered a raw-food vegan paleo diet nuts, that’s what I meant, that they just seem to difficult to reconcile.
My statement wasn’t an argument against meat; it was cautionary, and an appropriate response is to point out that I really like eating rice and beans, and should be equally cautious about arguing for their health benefits because of the stake I have in wanting those to be healthful.
My point about bread was that a 4oz piece of bread is not as unhealthy as a 4oz piece of hard candy. I don’t consider refined carbohydrates, or even unrefined but purer carbohydrates (such as potatoes) healthful. I’m having a lot of trouble finding good sources to either back me up or discredit what I’m trying to say (the video linked to earlier is one of the former), but the impression that I’m under is that starch doesn’t cause harmful insulin responses or large insulin spikes if eaten in the much less pure forms; that is, even significant quantities of carbohydrates are digested slowly enough to not cause problems if they are molecularly dispersed among protein, fats, or most especially fiber, and that this is a super-linear effect, more than would be explained simply by eating less of a pure carbohydrate.
I’m not too sure on what differences there are between starch and carbohydrates more generally but I believe it is true that insulin response is lower when carbohydrates are consumed in the form of foods with other components. This is the basic reasoning behind getting your carbs in the form of fruits and vegetables (which also provide plentiful fiber) rather than grains and tubers in paleo type diets. I’ve even seen it claimed that you are better off ordering fries rather than baked potato because the fat slows the rate of absorption but I don’t know how well sourced that is.
Potatoes (not baked), bananas, wild rice and other similar medium GI foods are generally viewed as ok in small quantities by the paleo diet resources I’ve read. They still provoke significantly greater glucose response than things like green vegetables, fruits and berries however while having less overall nutritional value and not significantly greater fiber content.
People generally eat baked potatoes with butter, cheese, and/or sour cream—not to mention meat.
For practical purposes, the carbs in a baked potato are very likely to be buffered with fat and protein.
I bet french fries could be better than a baked potato, but for that to be the case I think they would have to be unsalted (though the potassium in potatoes partially counteracts the salt) and fried in more healthful oils (probably saturated, since heat + unsaturated oil → trans fats). This sounds like an experiment worth performing on myself; I like making french fries, and I could see how satiated I feel after a similar calorie-worth of french fries versus baked potato, and how I feel an hour later (more or less sluggish). I don’t eat much potato in any form, but answering that question (at least with regard to myself) might be a worthy enterprise.
I personally think bananas are great, but it seems like they don’t fit into the paleo scheme because they are so dramatically different than anything that existed in our ancestral environment. Wild potatoes are too toxic for humans to eat, even cooked IIRC.
I’ve also heard a plausible theory that a lot of the soil that food is grown on is mineral-depleted. Manure isn’t going to solve the problem if it’s from animals which have been fed food grown on mineral-depleted soil.
And I’ve wondered whether there are any important nutrients in insects.
I’m not sure what the name of the bias is but I’d have probably had the same reaction as you if I’d seen the paleo diet associated with homeopathy or crystal healing. My impression is that it is over-represented in the contrarian cluster that is over-represented on LessWrong (atheist, libertarian, software engineer, not given to an interest in homeopathy or crystal healing) but that might just be some kind of selection bias on my part. I tend to associate raw-food / vegan eating with the nutty new-age fringe and have the same kind of negative associations with those diets as you describe for that reason.
I would imagine you could get pretty close to a paleo type diet without stopping cooking your food or eating mammals if you are ok with eating fish / seafood, eggs and cheese / dairy. It’s pretty difficult to do it without cutting out grains however. I didn’t find that too difficult (well, except beer) because I could always take or leave bread / rice / pasta anyway but I’ve heard from people who really enjoyed those foods that after a (sometimes difficult) period of adjustment they adapted to a grain free diet quite well.