56 replies to this topic

[churchill]

I am not missing the diet aspect, I am saying it is very minor when put up against the huge selection pressure for health that was occuring at that time.

Then we will have to agree to disagree. I only say that if you want to live a long and healthy life you should pay attention to what you eat and learn as much as you can. Just because everyone else takes the slow poison doesn't mean you have to as well. I don't know you (in person) though and haven't seen what you eat. It is not always easy to eat healthy when there is a lot of people in society using their false status and official positions to mislead us.

The dollar is weak and always getting weaker but not until we recognise this we ourselves become strong.

I am happy to change my opinion if you present compelling evidence, are you? I am trying to get to the root of why you have this strongly held belief? At the moment I believe it is because you have fallen into the naturalistic fallacy. What I explained follow pretty clearly if you believe that primitive existence was harsh (do you disagree with that?) and you believe in natural selection. And your evidence for your opinion that the primitive diet explains the 'health' of primitive society is what exactly?

[rwac]

I am happy to change my opinion if you present compelling evidence, are you? I am trying to get to the root of why you have this strongly held belief? At the moment I believe it is because you have fallen into the naturalistic fallacy. What I explained follow pretty clearly if you believe that primitive existence was harsh (do you disagree with that?) and you believe in natural selection. And your evidence for your opinion that the primitive diet explains the 'health' of primitive society is what exactly?

From http://wholehealthso...ization_28.html
Things can change in a single generation when diet changes.

The Xavante of Simoes Lopes
...
The most striking thing about these data is the occlusion of the Xavante. 95 percent had ideal occlusion. The remaining 5 percent had nothing more than a mild crowding of the incisors (front teeth). Niswander didn't observe a single case of underbite or overbite.
...
data on another nearby (and genetically similar) tribe called the Bakairi that had been using a substantial amount of modern foods for some time. The Bakairi, living right next to the Xavante but eating modern foods from the trading post, had 9 times more malocclusion and nearly 10 times more cavities than the Xavante.
...
The Masai of Kenya

The Masai are traditionally a pastoral people who live almost exclusively from their cattle. In 1945, and again in 1952, Dr. J. Schwartz examined the teeth of 408 and 273 Masai, respectively (#1 free full text; #2 ref). In the first study, he found that 8 percent of Masai showed some form of malocclusion, while in the second study, only 0.4 percent of Masai were maloccluded. Although we don't know what his precise criteria were for diagnosing malocclusion, these are still very low numbers.
...
A paper from 1992 described their modern diet:

The main articles of diet were white maize, [presumably heavily sweetened] tea, milk, [white] rice, and beans. Traditional items were rarely eaten... Milk... was not mentioned by 30% of mothers.

A paper from 1993 described the occlusion of 235 young Masai attending rural and peri-urban schools. Nearly all showed some degree of malocclusion, with open bite alone affecting 18 percent.
...

Rural Caucasians in Kentucky
...
The older generation of this population has the best occlusion of any Caucasian population I've ever seen, rivaling some hunter-gatherer groups. This shows that Caucasians are not genetically doomed to malocclusion. The younger generation, living on more modern foods, shows very poor occlusion, among the worst I've seen. They also show narrowed arches, a characteristic feature of deteriorating occlusion. One generation is all it takes. Corruccini found that a higher malocclusion score was associated with softer, more industrial foods.

Edited by rwac, 17 September 2010 - 05:55 PM.

[caston]

I am happy to change my opinion if you present compelling evidence, are you? I am trying to get to the root of why you have this strongly held belief? At the moment I believe it is because you have fallen into the naturalistic fallacy. What I explained follow pretty clearly if you believe that primitive existence was harsh (do you disagree with that?) and you believe in natural selection. And your evidence for your opinion that the primitive diet explains the 'health' of primitive society is what exactly?

OK well it is from my own life observations and reasoning and reading information and remembering what I read but not always remembers where I read it. I am starting to remember some of it now though. I have read a book about sugar but I forget exactly what it was called the one I link to further down *may* be it.

What did you think of the "nutrition and physical degeneration" project guttenberg book? The guy traveled the world looking at the effect of diet on Malocclusion and tooth decay.

Some of the royal family even ended up with black teeth because they enjoyed the spoils of sugar beet trade so much. Sugar is quite interesting really in how it has shaped our history.

http://www.elizabeth...yths/myth17.htm

http://avaxhome.ws/e...1865086576.html


I don't disagree with the primitive existence being harsh just that when humans have things a bit easier they will spoil themselves rotten. Now you may still want more references if you aren't satisfied but on this lazy Saturday afternoon that's all I have given you so far.

And on this lazy Saturday afternoon I will link periodontal disease to heart disease with a lazy google video embedment:

http://video.google....55136334935407#

Edited by caston, 18 September 2010 - 05:47 AM.

[caston]

rwac:

I also want to thank you for your link and I found another interesting post on that blog site:

http://wholehealthso...y-on-wheat.html

Edited by caston, 18 September 2010 - 05:59 AM.

[churchill]

Had a look at the Gutenberg ebook. I agree with he premise that primitive man had better kept teeth than modern man, but I don't really regard tooth decay as a sign that we are less healthy. I do agree that it is as a consequence of our change in diet from primitive times, but I am happy with this scenario as it means I get to eat cake and sweets, which is something I personally quite enjoy (what is the point of living a long life if you can't get to do what you like). So there is a trade off, but I still see myself as 'healthy' as as long as I go to the dentist regularly and brush floss gargle regularly.

Similarly with myopia, this is partially caused by too much reading and tv watching, and I am sure primitive cultures did not have the endemic short sightedness which occurs in modern cultures. It is pretty shocking but apparently 75% (of US) population uses some form of vision correction. http://www.glassescr...rs-glasses.html . I ended up getting laser eye surgery to correct mine. Again though I see this as a trade off, I would rather wear glasses and be able to read than go through life not doing this, and I don't believe I am less healthy.

The definition of what people perceive to be healthy varies between each person. My personal definitions is 'health is living long while still being able to carry out your daily activities'. Unfortunately health is such a vague term and gets quite abused, take cheese for example is it healthy? Well it has a lot of saturated fats, so I would say no, but it also has calcium which is vital and so in some respects yes, you could argue that you could supplement calcium. Is a champion body builder healthy? Is a 100 metre runner healthy? Or is the long distance runner more healthy? If you do lots of exercise is it good for you? But if you do too much then you can damage your joints and risk an injury. If you are older this can be a large risk as a broken hip for example increases your likelihood of dying even if the hip is replaced.

[caston]

At least with cake and sweets you know its cake and sweets but there are many carb rich foods such as breads and wheat which cause a spike in blood glucose. These foods which are considered staples are more dangerous than sweets which are consumed in moderation and yes as you say make life enjoyable.

[rwac]

Similarly with myopia, this is partially caused by too much reading and tv watching, and I am sure primitive cultures did not have the endemic short sightedness which occurs in modern cultures. It is pretty shocking but apparently 75% (of US) population uses some form of vision correction. http://www.glassescr...rs-glasses.html . I ended up getting laser eye surgery to correct mine. Again though I see this as a trade off, I would rather wear glasses and be able to read than go through life not doing this, and I don't believe I am less healthy.

You blame it on reading, but it's the diet at fault here.
From http://www.karlloren...iabetes/p49.htm

"Overnight Epidemics"

While fewer than one per cent of the Inuit and Pacific islanders had myopia early in the last century, these rates have since skyrocketed to as high as 50 per cent. These "overnight epidemics" have usually been blamed on the increase in reading following the sudden advent of literacy and compulsory schooling in these societies.

But while reading may play a role, it does not explain why the incidence of myopia has remained low in societies that have adopted Western lifestyles but not Western diets, says Cordain.

"In the islands of Vanuatu they have eight hours of compulsory schooling a day," he says, "yet the rate of myopia in these children is only two per cent." The difference is that Vanuatuans eat fish, yam and coconut rather than white bread and cereals.

http://www.ncbi.nlm..../pubmed/3875961
http://www.ncbi.nlm..../pubmed/2853534

The definition of what people perceive to be healthy varies between each person. My personal definitions is 'health is living long while still being able to carry out your daily activities'. Unfortunately health is such a vague term and gets quite abused, take cheese for example is it healthy? Well it has a lot of saturated fats, so I would say no, but it also has calcium which is vital and so in some respects yes, you could argue that you could supplement calcium. Is a champion body builder healthy? Is a 100 metre runner healthy? Or is the long distance runner more healthy? If you do lots of exercise is it good for you? But if you do too much then you can damage your joints and risk an injury. If you are older this can be a large risk as a broken hip for example increases your likelihood of dying even if the hip is replaced.

The problem is that there's no evidence at all to suggest that saturated fat is bad in people. None.
It seems to be a general consensus that excess calcium is bad for you, atleast on this board.

There's evidence that suggests that the long distance runner is actually less healthy

The runners had completed a minimum of five marathons in the prior three years. By standard measures, the group’s risk for heart problems was low. But when the researchers studied the runners’ scan results, they found that more than a third of the men showed evidence of significant calcification or plaque build-up in their heart arteries. Several also had scarring of some of the tissue in their hearts. “In our study,” the researchers concluded dryly, “regular marathon running seems not to protect runners” from coronary artery disease. “In fact,” they continued, “we even cannot exclude the possibility that exercise to this degree has deleterious effects on coronary arteries.”

http://well.blogs.ny...ect-your-heart/

[churchill]

Similarly with myopia, this is partially caused by too much reading and tv watching, and I am sure primitive cultures did not have the endemic short sightedness which occurs in modern cultures. It is pretty shocking but apparently 75% (of US) population uses some form of vision correction. http://www.glassescr...rs-glasses.html . I ended up getting laser eye surgery to correct mine. Again though I see this as a trade off, I would rather wear glasses and be able to read than go through life not doing this, and I don't believe I am less healthy.

You blame it on reading, but it's the diet at fault here.
From http://www.karlloren...iabetes/p49.htm

"Overnight Epidemics"

While fewer than one per cent of the Inuit and Pacific islanders had myopia early in the last century, these rates have since skyrocketed to as high as 50 per cent. These "overnight epidemics" have usually been blamed on the increase in reading following the sudden advent of literacy and compulsory schooling in these societies.

But while reading may play a role, it does not explain why the incidence of myopia has remained low in societies that have adopted Western lifestyles but not Western diets, says Cordain.

"In the islands of Vanuatu they have eight hours of compulsory schooling a day," he says, "yet the rate of myopia in these children is only two per cent." The difference is that Vanuatuans eat fish, yam and coconut rather than white bread and cereals.

http://www.ncbi.nlm..../pubmed/3875961
http://www.ncbi.nlm..../pubmed/2853534

The definition of what people perceive to be healthy varies between each person. My personal definitions is 'health is living long while still being able to carry out your daily activities'. Unfortunately health is such a vague term and gets quite abused, take cheese for example is it healthy? Well it has a lot of saturated fats, so I would say no, but it also has calcium which is vital and so in some respects yes, you could argue that you could supplement calcium. Is a champion body builder healthy? Is a 100 metre runner healthy? Or is the long distance runner more healthy? If you do lots of exercise is it good for you? But if you do too much then you can damage your joints and risk an injury. If you are older this can be a large risk as a broken hip for example increases your likelihood of dying even if the hip is replaced.

The problem is that there's no evidence at all to suggest that saturated fat is bad in people. None.
It seems to be a general consensus that excess calcium is bad for you, atleast on this board.

There's evidence that suggests that the long distance runner is actually less healthy

The runners had completed a minimum of five marathons in the prior three years. By standard measures, the group’s risk for heart problems was low. But when the researchers studied the runners’ scan results, they found that more than a third of the men showed evidence of significant calcification or plaque build-up in their heart arteries. Several also had scarring of some of the tissue in their hearts. “In our study,” the researchers concluded dryly, “regular marathon running seems not to protect runners” from coronary artery disease. “In fact,” they continued, “we even cannot exclude the possibility that exercise to this degree has deleterious effects on coronary arteries.”

http://well.blogs.ny...ect-your-heart/

The studies you cite on the prevalence of low myopia in Vanuatu, do you have the full contents of those as the abstract does not state much. From reading it though the researchers believe that it is genetic factors not diet which is probably the cause. You believe that the researchers did the research correctly but that their conclusions are flawed?

Apparently 80% of Vanuatu is still rural so it could be that they just work with a blackboard and no close reading, and very little close reading at home. So just because they go to school for 8 hours does not mean that they are close reading of books for 8 hours. If you have more details for the teaching methods and the prevalance of book usage in the general population that would help cut out this possible issue with your line of reasoning. [1]

Thanks for the information on the saturated fats, that was a complete misconception I had and it seems like many government health sites are still giving the outdated advice, one of the things I had been doing to try and reduce my LDL was cut out dairy products like cheese, so this is a completely the wrong angle to take it seems. From the wikipedia article it is suggested to avoid trans fats and stick to low GI foods would you agree with that?[2]. Just to check the rest of my knowledge as clearly you have done more research than I have... trans fats bad? high HDL good? low LDL good? high trygicerides good?

[rwac]

The studies you cite on the prevalence of low myopia in Vanuatu, do you have the full contents of those as the abstract does not state much. From reading it though the researchers believe that it is genetic factors not diet which is probably the cause. You believe that the researchers did the research correctly but that their conclusions are flawed?

Apparently 80% of Vanuatu is still rural so it could be that they just work with a blackboard and no close reading, and very little close reading at home. So just because they go to school for 8 hours does not mean that they are close reading of books for 8 hours. If you have more details for the teaching methods and the prevalance of book usage in the general population that would help cut out this possible issue with your line of reasoning. [1]

I do believe their conclusions are flawed. I presume they would have noted the difference between reading on a blackboard and a book, before blaming it on genetics, that would have been the obvious first thing to check.

Thanks for the information on the saturated fats, that was a complete misconception I had and it seems like many government health sites are still giving the outdated advice, one of the things I had been doing to try and reduce my LDL was cut out dairy products like cheese, so this is a completely the wrong angle to take it seems. From the wikipedia article it is suggested to avoid trans fats and stick to low GI foods would you agree with that?[2]. Just to check the rest of my knowledge as clearly you have done more research than I have... trans fats bad? high HDL good? low LDL good? high trygicerides good?

Trans fats are bad, High HDL is good.
There's good LDL ("fluffy") and bad LDL ("small, dense"), and LDL values are calculated mostly anyway, so don't put any weight in them.
Not sure about triglycerides.

Be wary of high insulin/glucose levels, both are damaging. You can test it yourself at home using a glucose meter.
Check your fasting glucose and do the oral glucose tolerance test.

One way to reduce LDL is to cut carbs, go wheat-free (If you want to go that route. Look to Dr. Davis for a reasonable guideline)
Lower GI is good, but watch out for anti-nutrients like phytic acid which can leech calcium and other minerals from your teeth, bones and body.

[churchill]

The studies you cite on the prevalence of low myopia in Vanuatu, do you have the full contents of those as the abstract does not state much. From reading it though the researchers believe that it is genetic factors not diet which is probably the cause. You believe that the researchers did the research correctly but that their conclusions are flawed?

Apparently 80% of Vanuatu is still rural so it could be that they just work with a blackboard and no close reading, and very little close reading at home. So just because they go to school for 8 hours does not mean that they are close reading of books for 8 hours. If you have more details for the teaching methods and the prevalance of book usage in the general population that would help cut out this possible issue with your line of reasoning. [1]

I do believe their conclusions are flawed. I presume they would have noted the difference between reading on a blackboard and a book, before blaming it on genetics, that would have been the obvious first thing to check.

Thanks for the information on the saturated fats, that was a complete misconception I had and it seems like many government health sites are still giving the outdated advice, one of the things I had been doing to try and reduce my LDL was cut out dairy products like cheese, so this is a completely the wrong angle to take it seems. From the wikipedia article it is suggested to avoid trans fats and stick to low GI foods would you agree with that?[2]. Just to check the rest of my knowledge as clearly you have done more research than I have... trans fats bad? high HDL good? low LDL good? high trygicerides good?

Trans fats are bad, High HDL is good.
There's good LDL ("fluffy") and bad LDL ("small, dense"), and LDL values are calculated mostly anyway, so don't put any weight in them.
Not sure about triglycerides.

Be wary of high insulin/glucose levels, both are damaging. You can test it yourself at home using a glucose meter.
Check your fasting glucose and do the oral glucose tolerance test.

One way to reduce LDL is to cut carbs, go wheat-free (If you want to go that route. Look to Dr. Davis for a reasonable guideline)
Lower GI is good, but watch out for anti-nutrients like phytic acid which can leech calcium and other minerals from your teeth, bones and body.

I think also it may be that it is important to identify whether other activities are popular in Vanuatu after school, such as hunting which mainly require long distance vision usage, which may counter balance the effect of reading short distances. I would tend to believe that if someone comes up with a flawed conclusion then their research as a whole is also flawed. Have you actually read the paper to find out more? I find it quite frustrating that scientific papers are locked behind a paywall.

How do you explain the high incidence in South Korea of myopia given that their diet has very little wheat?

Found this link on myopia rates in various countries...
http://www.agingeye.net/myopia/3.1.php
One extract...
Sherpa and Tibetan children in Nepal have the same ancestry and genetic history, but the prevalence of myopia is 2.7% for Sherpa children and 21.7% for Tibetan children98. This difference was attributed to more rigorous schooling and higher advanced technology in Tibet.
Diet wise neither seems to be dominated by wheat. Note the conclusion.

The weight of evidence I find is for myopia being caused by too much close reading.

[rwac]

I think also it may be that it is important to identify whether other activities are popular in Vanuatu after school, such as hunting which mainly require long distance vision usage, which may counter balance the effect of reading short distances. I would tend to believe that if someone comes up with a flawed conclusion then their research as a whole is also flawed. Have you actually read the paper to find out more? I find it quite frustrating that scientific papers are locked behind a paywall.

I agree it's frustrating.

How do you explain the high incidence in South Korea of myopia given that their diet has very little wheat?

Found this link on myopia rates in various countries...
http://www.agingeye.net/myopia/3.1.php
One extract...
Sherpa and Tibetan children in Nepal have the same ancestry and genetic history, but the prevalence of myopia is 2.7% for Sherpa children and 21.7% for Tibetan children98. This difference was attributed to more rigorous schooling and higher advanced technology in Tibet.
Diet wise neither seems to be dominated by wheat. Note the conclusion.

The weight of evidence I find is for myopia being caused by too much close reading.

I believe myopia is linked to high insulin. The mention of wheat was in reference to reducing LDL levels.

[churchill]

I think also it may be that it is important to identify whether other activities are popular in Vanuatu after school, such as hunting which mainly require long distance vision usage, which may counter balance the effect of reading short distances. I would tend to believe that if someone comes up with a flawed conclusion then their research as a whole is also flawed. Have you actually read the paper to find out more? I find it quite frustrating that scientific papers are locked behind a paywall.

I agree it's frustrating.

How do you explain the high incidence in South Korea of myopia given that their diet has very little wheat?

Found this link on myopia rates in various countries...
http://www.agingeye.net/myopia/3.1.php
One extract...
Sherpa and Tibetan children in Nepal have the same ancestry and genetic history, but the prevalence of myopia is 2.7% for Sherpa children and 21.7% for Tibetan children98. This difference was attributed to more rigorous schooling and higher advanced technology in Tibet.
Diet wise neither seems to be dominated by wheat. Note the conclusion.

The weight of evidence I find is for myopia being caused by too much close reading.

I believe myopia is linked to high insulin. The mention of wheat was in reference to reducing LDL levels.

The link you provided:
http://www.karlloren...iabetes/p49.htm
Mentioned the change in wheat production technique specifically as a trigger for the myopia, but if your basic premise is it is more diets high in refined starches such as breads and cereals increase which insulin levels, which then causes the myopia, the points about the diet of these countries still applies, as they are not heavily based on these food groups.

[rwac]

The link you provided:
http://www.karlloren...iabetes/p49.htm
Mentioned the change in wheat production technique specifically as a trigger for the myopia, but if your basic premise is it is more diets high in refined starches such as breads and cereals increase which insulin levels, which then causes the myopia, the points about the diet of these countries still applies, as they are not heavily based on these food groups.

No, it's specifically insulin resistance. Some people do just fine on a high carb diet.

btw, South Korea also has high levels of type 2 diabetes, which fits perfectly with this hypothesis.
http://care.diabetes...ontent/18/4/545

[churchill]

The link you provided:
http://www.karlloren...iabetes/p49.htm
Mentioned the change in wheat production technique specifically as a trigger for the myopia, but if your basic premise is it is more diets high in refined starches such as breads and cereals increase which insulin levels, which then causes the myopia, the points about the diet of these countries still applies, as they are not heavily based on these food groups.

No, it's specifically insulin resistance. Some people do just fine on a high carb diet.

btw, South Korea also has high levels of type 2 diabetes, which fits perfectly with this hypothesis.
http://care.diabetes...ontent/18/4/545

Your premise though is that insulin resistance is caused by a specific diet?

[rwac]

Your premise though is that insulin resistance is caused by a specific diet?

Diet and genetics, of course. Some people are more susceptible to high carb diets than others.

[churchill]

Your premise though is that insulin resistance is caused by a specific diet?

Diet and genetics, of course. Some people are more susceptible to high carb diets than others.

So your line of reasoning in this case is that diet (and genetics) causes insulin resistance which causes myopia?

The following document outlines the historical changes in the South Korean diet. To me it looks like they have gone from a high carb diet towards a higher protein diet rather than the other way around?

[rwac]

So your line of reasoning in this case is that diet (and genetics) causes insulin resistance which causes myopia?

The following document outlines the historical changes in the South Korean diet. To me it looks like they have gone from a high carb diet towards a higher protein diet rather than the other way around?

That's the reasoning.

Carbs in general don't cause insulin resistance. There are primitive societies which eat sweet potato as a significant source of calories, and they have low rates of insulin resistance.

I find it interesting that there's no mention of sugar consumption in the document, though. The following chart only goes back to 1985, but it's instructive.

http://books.google....20sugar&f=false

[churchill]

So your line of reasoning in this case is that diet (and genetics) causes insulin resistance which causes myopia?

The following document outlines the historical changes in the South Korean diet. To me it looks like they have gone from a high carb diet towards a higher protein diet rather than the other way around?

That's the reasoning.

Carbs in general don't cause insulin resistance. There are primitive societies which eat sweet potato as a significant source of calories, and they have low rates of insulin resistance.

I find it interesting that there's no mention of sugar consumption in the document, though. The following chart only goes back to 1985, but it's instructive.

http://books.google....20sugar&f=false

Just before you wrote..

Diet and genetics, of course. Some people are more susceptible to high carb diets than others.

Susceptible to what? I assumed you were talking about susceptible to insulin resistance?

[rwac]

Just before you wrote..

Diet and genetics, of course. Some people are more susceptible to high carb diets than others.

Susceptible to what? I assumed you were talking about susceptible to insulin resistance?

Yeah, susceptible to developing insulin resistance.

[churchill]

Just before you wrote..

Diet and genetics, of course. Some people are more susceptible to high carb diets than others.

Susceptible to what? I assumed you were talking about susceptible to insulin resistance?

Yeah, susceptible to developing insulin resistance.

So the evidence that in South Koreans are switching away from carbs while still having an increased myopia rates and at the same time having a much higher level of short sight usage occurring in the general population, would suggest that the myopia is not occurring due to the high carbs but due to change in vision usage patterns.

[rwac]

So the evidence that in South Koreans are switching away from carbs while still having an increased myopia rates and at the same time having a much higher level of short sight usage occurring in the general population, would suggest that the myopia is not occurring due to the high carbs but due to change in vision usage patterns.

I don't see how you can conclude that without looking at the confounding sugar intake.

Fructose, weight gain, and the insulin resistance syndrome
Sharon S Elliott, Nancy L Keim, Judith S Stern, Karen Teff and Peter J Havel
ABSTRACT
This review explores whether fructose consumption might be a contributing factor to the development of obesity and the accompanying metabolic abnormalities observed in the insulin resistance syndrome. The per capita disappearance data for fructose from the combined consumption of sucrose and high-fructose corn syrup have increased by 26%, from 64 g/d in 1970 to 81 g/d in 1997. Both plasma insulin and leptin act in the central nervous system in the long-term regulation of energy homeostasis. Because fructose does not stimulate insulin secretion from pancreatic ß cells, the consumption of foods and beverages containing fructose produces smaller postprandial insulin excursions than does consumption of glucose-containing carbohydrate. Because leptin production is regulated by insulin responses to meals, fructose consumption also reduces circulating leptin concentrations. The combined effects of lowered circulating leptin and insulin in individuals who consume diets that are high in dietary fructose could therefore increase the likelihood of weight gain and its associated metabolic sequelae. In addition, fructose, compared with glucose, is preferentially metabolized to lipid in the liver. Fructose consumption induces insulin resistance, impaired glucose tolerance, hyperinsulinemia, hypertriacylglycerolemia, and hypertension in animal models. The data in humans are less clear. Although there are existing data on the metabolic and endocrine effects of dietary fructose that suggest that increased consumption of fructose may be detrimental in terms of body weight and adiposity and the metabolic indexes associated with the insulin resistance syndrome, much more research is needed to fully understand the metabolic effect of dietary fructose in humans.

http://www.ajcn.org/...t/full/76/5/911

[churchill]

So the evidence that in South Koreans are switching away from carbs while still having an increased myopia rates and at the same time having a much higher level of short sight usage occurring in the general population, would suggest that the myopia is not occurring due to the high carbs but due to change in vision usage patterns.

I don't see how you can conclude that without looking at the confounding sugar intake.

Fructose, weight gain, and the insulin resistance syndrome
Sharon S Elliott, Nancy L Keim, Judith S Stern, Karen Teff and Peter J Havel
ABSTRACT
This review explores whether fructose consumption might be a contributing factor to the development of obesity and the accompanying metabolic abnormalities observed in the insulin resistance syndrome. The per capita disappearance data for fructose from the combined consumption of sucrose and high-fructose corn syrup have increased by 26%, from 64 g/d in 1970 to 81 g/d in 1997. Both plasma insulin and leptin act in the central nervous system in the long-term regulation of energy homeostasis. Because fructose does not stimulate insulin secretion from pancreatic ß cells, the consumption of foods and beverages containing fructose produces smaller postprandial insulin excursions than does consumption of glucose-containing carbohydrate. Because leptin production is regulated by insulin responses to meals, fructose consumption also reduces circulating leptin concentrations. The combined effects of lowered circulating leptin and insulin in individuals who consume diets that are high in dietary fructose could therefore increase the likelihood of weight gain and its associated metabolic sequelae. In addition, fructose, compared with glucose, is preferentially metabolized to lipid in the liver. Fructose consumption induces insulin resistance, impaired glucose tolerance, hyperinsulinemia, hypertriacylglycerolemia, and hypertension in animal models. The data in humans are less clear. Although there are existing data on the metabolic and endocrine effects of dietary fructose that suggest that increased consumption of fructose may be detrimental in terms of body weight and adiposity and the metabolic indexes associated with the insulin resistance syndrome, much more research is needed to fully understand the metabolic effect of dietary fructose in humans.

http://www.ajcn.org/...t/full/76/5/911

From the figures I presenting in the pdf, it looks like South Koreans have replaced their carbohydrate intake with protein, so even if their intake of fructose were also increasing you would not expect to see the dramatic increase in myopia, as the reduction in carbohydrate should counter balance the effect (this is assuming the causal link you have been talking about is true).

[rwac]

From the figures I presenting in the pdf, it looks like South Koreans have replaced their carbohydrate intake with protein, so even if their intake of fructose were also increasing you would not expect to see the dramatic increase in myopia, as the reduction in carbohydrate should counter balance the effect (this is assuming the causal link you have been talking about is true).

The only reference I made to lower carbs is this: "Some people are more susceptible to high carb diets than others."

(This is probably true for me personally, but not in general, thus the source of this mistake.)

I think it's inaccurate, as related to this discussion. It should have been better written as
"Some people are more susceptible to bad diets than others.".

Of course, once you have insulin resistance, you're more vulnerable to issues with carb intake.

Edited by rwac, 27 September 2010 - 01:06 PM.

[churchill]

From the figures I presenting in the pdf, it looks like South Koreans have replaced their carbohydrate intake with protein, so even if their intake of fructose were also increasing you would not expect to see the dramatic increase in myopia, as the reduction in carbohydrate should counter balance the effect (this is assuming the causal link you have been talking about is true).

The only reference I made to lower carbs is this: "Some people are more susceptible to high carb diets than others."

(This is probably true for me personally, but not in general, thus the source of this mistake.)

I think it's inaccurate, as related to this discussion. It should have been better written as
"Some people are more susceptible to bad diets than others.".

Of course, once you have insulin resistance, you're more vulnerable to issues with carb intake.

Talking population wide though, as these statistics are, you would still expect to see better myopia rates given there has been this shift away from carbs, assuming your theory were correct. But I guess that you are arguing that it is the higher fructose consumption that is actually causing the majority of the insulin resistance and myopia? What evidence do you have that this is true?

Also I wanted to check whether you believe it is also sucrose consumption which is also a significant factor? As previously you had quoted sucrose consumption in South Korea as being relevant?

The problem with any evidence which is looking at fructose is that this tends to move in lock step with a population which has weight gain, so how do you know if it is the weight gain or the frutose which is causing the problem? Also if you say fructose is bad are you advocating that eating fruit is bad?

[rwac]

Talking population wide though, as these statistics are, you would still expect to see better myopia rates given there has been this shift away from carbs, assuming your theory were correct. But I guess that you are arguing that it is the higher fructose consumption that is actually causing the majority of the insulin resistance and myopia? What evidence do you have that this is true?

Also I wanted to check whether you believe it is also sucrose consumption which is also a significant factor? As previously you had quoted sucrose consumption in South Korea as being relevant?

The problem with any evidence which is looking at fructose is that this tends to move in lock step with a population which has weight gain, so how do you know if it is the weight gain or the frutose which is causing the problem? Also if you say fructose is bad are you advocating that eating fruit is bad?

I think it's pretty well understood that fructose causes insulin resistance.
http://www.medicalne...cles/147135.php
http://www.ajcn.org/...t/full/76/5/911

You should watch this video:http://www.youtube.com/watch?v=dBnniua6-oM

Sucrose consists of a molecule of glucose and a molecule of fructose combined, and it is a good proxy for fructose consumption. (except in the US, where people consume a lot of HFCS)

Weight gain is also a consequence of the insulin resistance ...

[churchill]

Talking population wide though, as these statistics are, you would still expect to see better myopia rates given there has been this shift away from carbs, assuming your theory were correct. But I guess that you are arguing that it is the higher fructose consumption that is actually causing the majority of the insulin resistance and myopia? What evidence do you have that this is true?

Also I wanted to check whether you believe it is also sucrose consumption which is also a significant factor? As previously you had quoted sucrose consumption in South Korea as being relevant?

The problem with any evidence which is looking at fructose is that this tends to move in lock step with a population which has weight gain, so how do you know if it is the weight gain or the frutose which is causing the problem? Also if you say fructose is bad are you advocating that eating fruit is bad?

I think it's pretty well understood that fructose causes insulin resistance.
http://www.medicalne...cles/147135.php
http://www.ajcn.org/...t/full/76/5/911

You should watch this video:http://www.youtube.com/watch?v=dBnniua6-oM

Sucrose consists of a molecule of glucose and a molecule of fructose combined, and it is a good proxy for fructose consumption. (except in the US, where people consume a lot of HFCS)

Weight gain is also a consequence of the insulin resistance ...

Thanks for clearing that up, I did not realise that sucrose was composed of fructose + glucose.

Found this interesting study (on rats though) which suggest that the insulin resistance which occurs from eating sucrose goes away with exercise.
http://www.ajcn.org/...stract/38/6/879

Do you have any long term studies on insulin resistance and sucrose? I am interested to see if the insulin resistance continues as long as the heightened levels of sucrose are ingested or if the body adjusts to it after a time and the insulin resistance might go away.

[rwac]

Thanks for clearing that up, I did not realise that sucrose was composed of fructose + glucose.

Found this interesting study (on rats though) which suggest that the insulin resistance which occurs from eating sucrose goes away with exercise.
http://www.ajcn.org/...stract/38/6/879

Do you have any long term studies on insulin resistance and sucrose? I am interested to see if the insulin resistance continues as long as the heightened levels of sucrose are ingested or if the body adjusts to it after a time and the insulin resistance might go away.

As long as you don't deplete your glycogen stores (and the visceral fat), the insulin resistance will remain.

Essentially, insulin resistance is a mechanism to allow mammals to pack on the fat in summer, which is then used over the winter.
So eating "fruits" (or sugars) during the "summer" causes people to gain weight.
By eating them all year round, we are essentially overfilling those stores, and never emptying them.

And even if you do deplete them, some people's glucose metabolism remains broken...

Edited by rwac, 30 September 2010 - 04:37 PM.