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Author Topic:   Good Calories, Bad Calories, by Gary Taubes
PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 211 of 451 (470980)
06-13-2008 5:59 PM
Reply to: Message 206 by Percy
06-13-2008 8:43 AM


Re: Many public health recommendations are not truly evidence-based
quote:
Especially obvious will be who's living in denial.
Yes, when it is discovered that the slurs start in Message 188.
quote:
I wouldn't call it a proxy, but there's a correlation between low fat consumption and low cholesterol levels.
Then that limits the evidential value.
quote:
Here in the states, "low fat" is a major promotional tool, and has been for quite some time. You can get skim milk, 1% milk, 2% milk, low fat cheese, low fat cream cheese, no fat cream cheese (tastes like cardboard), extra lean meat, low fat sausage, etc.
Most of that is easily available, now. As I stated, though that was not the case in the '70s (although I've only seen the 1% and 2% milk recently despite shopping in four different stores quite regularly).
It's been a gradual development, though. You'd have found a lot less in the '80s. And then there are all the misleading promotions where the fat content hasn't changed.
quote:
The statistics do indicate that fat consumption has not declined but has actually increased slightly overall here in the states, which I of course accept, but it's hard to make sense of given all the low fat food in supermarkets, which wouldn't dominate shelf space if they weren't selling. I wonder what the explanation is.
Marantz et. al. point out that people are eating more which is one factor. Another may be a move towards eating more processed food - ready meals, especially.
quote:
Well, I guess I just wasn't able to work it out. Without links or quotes or something else to go on, the references to things said elsewhere were too difficult to figure out and track down. Perhaps you could state your point all in one place?
Percy, it seems that you weren't able to figure it out with the link, which I certainly didn't expect. Why would it be different if I tried again ?
quote:
Anyway, the part of your argument I don't understand is how the Marantz paper is damaging rather than supportive of Taubes' premise that dietary guidelines related to fat have contributed to the obesity epidemic.
Perhaps the fact that I say that the argument I am objecting to goes beyond that claim has something to do with that. (In fact I do point out that Marantz et al state that the evidence for even that is weak, and insufficent to conclude that it is true).
quote:
The OP says that Taubes believes that the elevated levels of what are traditionally called the diseases of western civilization, namely heart disease, diabetes and obesity, are due to carbohydrates, not dietary fat. The Marantz paper, while touching only on obesity, is supportive of this premise.
Not really. There is no way to conclude, for instance, that it was not simply the increase in calories consumed. There are any number of other possibilities to be considered. The paper simply doesn't have the data that would let us reach that conclusion.
quote:
Well, I guess I can see what you're getting at, but I think expressing it this way makes misinterpretation too likely
I'd say that it makes the contradiction more obvious.
If your comparison is one calorie in the form of glucose against another calorie in the form of glucose you wouldn't find a difference.
But reducing it to that level isn't valid.
In Message 173 you starkly state:
to the body there is no difference between carbohydrates and sugar
But there are differences. The presence of large amounts of fructose in sugar is a difference. The rate at which the glucose moves into the bloodstream is another which you recognise as being relevant in Message 8:
Refined carbohydrates, meaning carbohydrates unencumbered by much if any fiber, are particularly dangerous, and it isn't at all just the risk of obesity. Refined carbohydrates are digested exceptionally quickly and cause blood sugar spikes which in turn cause the liver to release LDLs that initially carry a large payload of cholesterol.
So there are at least two differences, which you consider (or have considered) significant - and completely leave out.

This message is a reply to:
 Message 206 by Percy, posted 06-13-2008 8:43 AM Percy has replied

Replies to this message:
 Message 212 by Percy, posted 06-13-2008 6:22 PM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 212 of 451 (470985)
06-13-2008 6:22 PM
Reply to: Message 211 by PaulK
06-13-2008 5:59 PM


Re: Many public health recommendations are not truly evidence-based
I don't think we're going to agree about what the available evidence indicates. You make a number of points about how I could better organize the presentation of information, and while I can't really disagree, it's sort of beside the point since it was the best I could do given my talent and time available. Where I left some information out, I think many of my posts were already somewhat lengthy, an argument for hoping people might remember information from previous posts.
--Percy
Edited by Percy, : Typo.

This message is a reply to:
 Message 211 by PaulK, posted 06-13-2008 5:59 PM PaulK has replied

Replies to this message:
 Message 214 by PaulK, posted 06-14-2008 5:46 AM Percy has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 213 of 451 (470991)
06-13-2008 8:31 PM


The Disappearing Food Pyramid
Some might remember the food pyramid I posted about a week ago, it looked like this:
This, of course, is the *old* food pyramid. A couple years ago the USDA (United States Department of Agriculture) revised the food pyramid and the new pyramid looks like this:
The new pyramid is a symbol rather than a pictorial representation of which food groups to emphasize or minimize. In order to find actual recommendations you have to work at it. The easiest way that I've come across for finding recommendations is to first go to http://www.mypyramid.gov/ and click on "Inside the Pyramid" in the left hand navigation bar. In the pyramid on this page, the triangular portions of the pyramid correspond to food groups, as you'll see by clicking on each triangle in turn. The orange triangle is grains, the green is vegetables, the red is fruits, the blue is milk products, and the purple is meats and beans. The breadth of each triangle appears to be an indication of how "recommended" each food group is.
Meat is still not favored, as the purple triangle is the smallest. If you click on the "Learn More" and then on the "Tips for making wise choices" in the right hand list of links, you'll see recommendations like "Start with a lean choice" and "Trim away all visible fat", so the USDA is still on the low-fat bandwagon concerning meat.
And also concerning milk products. Click on the blue triangle, then "Learn More", then "Tips to for making wise choices." They recommend skim milk (fat-free milk) and low fat cheese.
But they have changed their story on grains. Click on the orange triangle, then "Learn More", then "Tips to help you eat whole grains". They're recommending whole grains and deemphasizing refined products. This is definitely a positive development, because whole grains contain more fiber. Fiber is also a carbohydrate, but it's also indigestible - it makes no contribution to nutrition.
The new pyramid is an improvement in two ways. First, the information is more accurate. Second, it's so hard to find the actual recommendations that few will bother.
--Percy

PaulK
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Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 214 of 451 (471062)
06-14-2008 5:46 AM
Reply to: Message 212 by Percy
06-13-2008 6:22 PM


Re: Many public health recommendations are not truly evidence-based
I'm sorry but I don't think that your Message 173 can be saved by those means.
The message that all carbohydrates are as bad as sugar (let alone that they ARE sugar) is simply wrong.
"All carbohydrates are as bad as sugar if you ignore the reasons why sugar is worse" doesn't seem to be even worth saying.
"Excess glucose is bad, no matter what it's dietary source" also hardly seems worth saying. It is a better description of your argument, providing a valid reason to look at glucose alone and leaving out the emotive and misleading comparison with sugar. But it's hardly controversial - even the "dietary fat mafia" would agree with that.

This message is a reply to:
 Message 212 by Percy, posted 06-13-2008 6:22 PM Percy has replied

Replies to this message:
 Message 215 by Percy, posted 06-14-2008 7:59 AM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 215 of 451 (471076)
06-14-2008 7:59 AM
Reply to: Message 214 by PaulK
06-14-2008 5:46 AM


Re: Many public health recommendations are not truly evidence-based
PaulK writes:
I'm sorry but I don't think that your Message 173 can be saved by those means.
The message that all carbohydrates are as bad as sugar (let alone that they ARE sugar) is simply wrong.
Okay, you're welcome to your opinion. I like the provocative title, and I make clear in paragraph three the difference between glucose and fructose, though as I reread the message now I think I'd rewrite paragraph four like this:
Percy's rewrite of paragraph four in Message 173 writes:
The body cannot tell the difference between the glucose in carbohydrates from bread and pasta versus the glucose from sugar. To the body they are one and the same.
Moving on:
PaulK writes:
"Excess glucose is bad, no matter what it's dietary source" also hardly seems worth saying. It is a better description of your argument, providing a valid reason to look at glucose alone and leaving out the emotive and misleading comparison with sugar. But it's hardly controversial - even the "dietary fat mafia" would agree with that.
But I don't think the dietary fat mafia would agree about what constitutes excess glucose. The daily value for carbohydrates in the US is 300 grams, which is the equivalent amount of glucose as a half cup of sugar. A common recommendation is for carbohydrate sources to comprise 60-70% of total diet. A more reasonable level would be in the neighborhood of about 25%.
A certain proportion of the carbohydrates in most foods that contain them is fiber. Fiber is a form of indigestible carbohydrate that does not contribute to nutrition. Fiber is also often referred to as roughage. You can subtract the grams of fiber on the nutrition label from the grams of total carbohydrates to get a measure of the effective carbohydrate content.
It is because of its higher fiber content that the USDA recommends whole grain as opposed to refined grain sources, but for the most part this recommendation is useless because the whole grain product you'll usually find in supermarkets and restaurants differs very little from the refined grain product. For example, the D'Angelo's website lists this information for their large regular and whole wheat sub rolls (D'Angelo is a popular sub sandwich chain in central New England, all units in grams, the glucose and fructose figures are my calculations):
Total   Total    Total
Roll Type    Carbohydrate  Fiber  Sugars  Glucose  Fructose
-----------------------------------------------------------
Honey Wheat  88            6.3    9       86.2     4.5
White        90            3      6       90       3
As you can see, the honey wheat sub roll provides very little advantage over the white, plus it has 3 more grams of sugar, half of which is fructose. Also keep in mind that this is just the roll. The contents of the sub roll adds another 90-130 grams of carbohydrates. If you want to limit yourself to 100 grams/day of carbohydrates then you can never eat a large D'Angelo sub. You could have a small one, but only if you'd had nearly zero carbohydrates at both breakfast and lunch.
Why does D'Angelo offer a whole wheat sub roll that is almost the same nutritionally as its white? Well, it's an unfortunate fact that grain products that are significantly high in fiber have little appeal for modern palates. Some can be found in supermarkets, but truly high fiber products can usually only be found in health food stores or on the Internet. Most restaurants wouldn't think of including such products on their menu because the idea is to encourage people to eat. Placing such unappealing offerings on the menu would be counterproductive.
Before the development of agriculture around 10,000 years ago, all human diets were relatively low in non-fiber carbohydrates. Grains in any substantial quantity simply did not exist, and it took thousands of years after that for refined carbohydrate products to become widely available. Combined with the ready availability today of refined sugar in soda and candy, the modern western diet has far too much carbohydrate, and far, far, far more than our ancestors over the last few million years of evolution. Our bodies did not evolve to deal with high carbohydrate intake levels. This is not just Taubes saying this, but many other respected diet/health writers who have managed to not alienate the mainstream diet/health medical establishment, like Michael Pollan, author of The Omnivore's Dilemma.
Taubes makes a number of observations that taken together indicate that something important is going on with respect to carbohydrates that we do not yet understand:
  1. The obesity epidemic has coincided with increased intake of carbohydrates.
  2. Human metabolism with respect to weight gain is nowhere near as simple as "a calorie is a calorie is a calorie," as can seen with otherwise identical people on the same diet having different weight gain experiences.
  3. Transplantation of skin from a region of fat accumulation, such as the belly, to a region where fat accumulation is rare, such as the back of the hand, sees that tissue gain weight identically to where it came from throughout the subject's lifetime.
  4. Emaciation and obesity has been observed in the same individual simultaneously. Women emaciated above the waist and obese below is one example. Clearly something related to tissue metabolism, not diet, is the significant factor.
  5. Insulin regulation plays a key role in obesity because it encourages the conversion of fatty acids into triglycerides by adipose tissue (fat tissue), and insulin levels are strongly influenced by blood glucose levels, which are in turn influenced by carbohydrate intake.
  6. The progression from normal to metabolic syndrome to diabetes type II hints that elevated carbohydrate intake has a wearing effect on body metabolism for susceptible individuals, primarily the pancreas and its production of insulin. Unfortunately, susceptible individuals represent a significant proportion of most populations.
Taubes and the mainstream diet/health establishment part company over the implications of these observations regarding carbohydrates. They especially part company regarding Taubes' support of the possibility that carbohydrates are also implicated in heart disease because of their contribution to small, dense LDL production, but that's another matter.
--Percy

This message is a reply to:
 Message 214 by PaulK, posted 06-14-2008 5:46 AM PaulK has replied

Replies to this message:
 Message 216 by PaulK, posted 06-14-2008 4:02 PM Percy has replied

PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 216 of 451 (471114)
06-14-2008 4:02 PM
Reply to: Message 215 by Percy
06-14-2008 7:59 AM


Re: Many public health recommendations are not truly evidence-based
quote:
Okay, you're welcome to your opinion. I like the provocative title, and I make clear in paragraph three the difference between glucose and fructose...
You say that there's a difference, but nowhere do you hint that the fructose is even possibly more harmful. But it's interesting that you don't consider it important that the title isn't true.
quote:
But I don't think the dietary fat mafia would agree about what constitutes excess glucose. The daily value for carbohydrates in the US is 300 grams, which is the equivalent amount of glucose as a half cup of sugar. A common recommendation is for carbohydrate sources to comprise 60-70% of total diet. A more reasonable level would be in the neighborhood of about 25%.
The question of what is excess is open to question. But does that really matter. Your body needs glucose, and it seems to be better to get that from starchy foods than sugar.

This message is a reply to:
 Message 215 by Percy, posted 06-14-2008 7:59 AM Percy has replied

Replies to this message:
 Message 217 by Percy, posted 06-14-2008 4:08 PM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 217 of 451 (471118)
06-14-2008 4:08 PM
Reply to: Message 216 by PaulK
06-14-2008 4:02 PM


Re: Many public health recommendations are not truly evidence-based
PaulK writes:
You say that there's a difference, but nowhere do you hint that the fructose is even possibly more harmful. But it's interesting that you don't consider it important that the title isn't true.
Sure it's true.
The question of what is excess is open to question. But does that really matter. Your body needs glucose, and it seems to be better to get that from starchy foods than sugar.
It's true that the body needs glucose, but it does not require dietary carbohydrates. You can't live without dietary protein, you can't live without dietary fat, but you can live just fine without dietary carbohydrates.
--Percy

This message is a reply to:
 Message 216 by PaulK, posted 06-14-2008 4:02 PM PaulK has replied

Replies to this message:
 Message 219 by PaulK, posted 06-15-2008 7:00 AM Percy has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 218 of 451 (471147)
06-15-2008 5:19 AM


No carbs, no glucose? No way!
One of the questions I asked early in this thread, and that still hasn't been answered, is where glucose comes from on low-carbohydrate diets. I now think I have the glimmer of an answer. A process called gluconeogenesis is employed by the liver to produce glucose from amino acids and glycerol obtained from fats.
That's the short answer. There's a longer answer at Wikipedia (see the Wikipedia article on Gluconeogenesis). I sort of slogged my way through it, but I didn't get much out of it, it would be nice if someone could put it in lay terms. I'm particularly interested in the parts of the process that are exercise-induced.
Evidently gluconeogenesis is often associated with ketosis, another liver process that produces fatty acids for use as energy by the body. So in the absence of carbohydrates, the liver produces both glucose and fatty acids. This would explain why carbohydrates are not a necessary nutrient.
An aside: I've been able to answer another question that came up earlier in the thread concerning where the triglycerides produced by the liver are stored. Taubes states on page 175:
Taubes on page 175 writes:
After we eat a carbohydrate-rich mean, the bloodstream is flooded with glucose, and the liver takes some of this glucose and transforms it into fat—i.e., triglycerides—for temporary storage.
I assumed the triglycerides were stored in the liver, and Molbiogirl objected that this couldn't possibly be true, and in that she was correct. The storage medium for the triglycerides produced by the liver appears to be the bloodstream.
--Percy

PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 219 of 451 (471158)
06-15-2008 7:00 AM
Reply to: Message 217 by Percy
06-14-2008 4:08 PM


Re: Many public health recommendations are not truly evidence-based
quote:
Sure it's true.
You've already agreed that not only is it not literally true, there arwe important factors that make sugar the worst form of carbohydrates.
So, no it isn't true that "all carbohydrates are sugar".
quote:
It's true that the body needs glucose, but it does not require dietary carbohydrates.
It's just as well that I didn't state that dietary carbohydrates are necessary then. Only that starchy foods are in general better than sugar. And we already know that you agree with that.

This message is a reply to:
 Message 217 by Percy, posted 06-14-2008 4:08 PM Percy has replied

Replies to this message:
 Message 220 by Percy, posted 06-15-2008 9:34 AM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 220 of 451 (471166)
06-15-2008 9:34 AM
Reply to: Message 219 by PaulK
06-15-2008 7:00 AM


Re: Many public health recommendations are not truly evidence-based
Carbohydrates range from the extremely simple (e.g., sucrose, better known as table sugar) to the very complex (e.g., potatoes and rice).
Very simple carbohydrates like sucrose are approximately 50% glucose and 50% fructose. Almost no digestive effort is required for sucrose to become glucose and fructose in the bloodstream. Food products like candy, pastry and soda are responsible for spikes in blood sugar due to the rapid increase in glucose in the bloodstream, while the liver is flooded with fructose that it converts to triglycerides. Elevated blood sugar causes increased insulin levels which in turn cause overproduction of triglycerides and their subsequent uptake by adipose tissue. This is the primary process by which the sugar in candy and soda makes you fat.
The advantage of very complex carbohydrates is that they take time to digest and so do not result in blood sugar spikes, but they are broken down by digestive processes into various forms of very simple carbohydrates, mostly glucose, which is the source of the message title "Carbohydrates are Sugar" that you didn't like. While the insulin response isn't dramatic, the increased insulin levels still encourage the uptake of triglycerides by adipose tissue.
But a meal of complex carbohydrates can be just as fattening as one of simple carbohydrates. One common example is Chinese pork fried rice. High in both fat and carbohydrate, the fat elevates triglyceride levels while the carbohydrate elevates insulin levels, causing adipose tissue to suck up the fat.
PaulK writes:
It's just as well that I didn't state that dietary carbohydrates are necessary then. Only that starchy foods are in general better than sugar. And we already know that you agree with that.
Sure. The very complex carbohydrates in starchy foods are preferable to the very simple carbohydrates in sugar. No carbohydrates are even better.
--Percy

This message is a reply to:
 Message 219 by PaulK, posted 06-15-2008 7:00 AM PaulK has replied

Replies to this message:
 Message 221 by PaulK, posted 06-15-2008 4:47 PM Percy has replied

PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 221 of 451 (471235)
06-15-2008 4:47 PM
Reply to: Message 220 by Percy
06-15-2008 9:34 AM


Starch vs sugar
quote:
Very simple carbohydrates like sucrose are approximately 50% glucose and 50% fructose.
Is that what you meant to write ? It's certainly not correct.
quote:
Sure. The very complex carbohydrates in starchy foods are preferable to the very simple carbohydrates in sugar. No carbohydrates are even better.
I'm far from certain that leaving out carbohydrates altogether would be a good idea. There are questions about the safety of long-term ketosis, so I'd be very surprised if no carbs was the healthiest option. (Not to mention the need to be very careful about your diet in other respects).

This message is a reply to:
 Message 220 by Percy, posted 06-15-2008 9:34 AM Percy has replied

Replies to this message:
 Message 222 by Percy, posted 06-15-2008 8:50 PM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 222 of 451 (471283)
06-15-2008 8:50 PM
Reply to: Message 221 by PaulK
06-15-2008 4:47 PM


Re: Starch vs sugar
PaulK writes:
quote:
Very simple carbohydrates like sucrose are approximately 50% glucose and 50% fructose.
Is that what you meant to write ? It's certainly not correct.
Yeah, it would probably be better phrased as, "Sucrose is an example of a very simple carbohydrate that is approximately 50% glucose and 50% fructose."
I'm far from certain that leaving out carbohydrates altogether would be a good idea.
So am I. The important issue underlying this entire thread is that the current conventional wisdom about diet and health is not supported by the available research. Teasing out diet/health relationships is proving incredibly difficult. So when you go on to say:
There are questions about the safety of long-term ketosis, so I'd be very surprised if no carbs was the healthiest option. (Not to mention the need to be very careful about your diet in other respects).
It is true that advocates of the dietary fat hypothesis question the advisability of diets that encourage ketosis. But they're probably confusing ketosis, a perfectly normal metabolic process, with ketoacidosis, a potentially dangerous condition often associated with diabetes. Given that some human populations have survived generations on meat-only diets (Eskimos, for example), the more serious questions would be about diets that include elevated levels of carbohydrates, particularly refined carbohydrates.
This passage from Taubes is relevant:
Taubes on page 319 writes:
Though glucose is a primary fuel for the brain, it is not, however, the only fuel, and dietary carbohydrates are not the only source of that glucose. If the diet includes less than 130 grams of carbohydrates, the liver increases its synthesis of molecules called ketone bodies, and these supply the necessary fuel for the brain and central nervous system. If the diet includes no carbohydrates at all, ketone bodies supply three-quarters of the energy to the brain. The rest comes from glucose synthesized from the amino acids in protein, either from the diet or from the breakdown of muscle, and from a compound called glycerol that is released when triglycerides in the fat tissue are broken down into their component fatty acids.
There's more that you might find interesting, but Taubes book is not on-line in any complete form and I have to type this in by hand.
--Percy

This message is a reply to:
 Message 221 by PaulK, posted 06-15-2008 4:47 PM PaulK has replied

Replies to this message:
 Message 223 by PaulK, posted 06-16-2008 7:30 AM Percy has replied

PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 223 of 451 (471343)
06-16-2008 7:30 AM
Reply to: Message 222 by Percy
06-15-2008 8:50 PM


Re: Starch vs sugar
quote:
So am I. The important issue underlying this entire thread is that the current conventional wisdom about diet and health is not supported by the available research
And Taubes' ideas don't seem to be any better supported.
quote:
Given that some human populations have survived generations on meat-only diets (Eskimos, for example), the more serious questions would be about diets that include elevated levels of carbohydrates, particularly refined carbohydrates.
Given that subsistence farmers have survived generations on high-carb diets it seems that these "more serious" questions are easily answered in exactly the same way.
(The traditional Inuit diet was rather special - they had little in the way of carbs due to availability rather than choice. They ate what they could get - including the stomach contents of animals they killed. They also ate their meat mainly raw, and ate a lot of blubber - which apparently contains a high proportion of unsaturated fat).
And if you want to appeal to our evolutionary history you must remember that humans are not obligate carnivores and did not evolve to eat an all-meat diet.

This message is a reply to:
 Message 222 by Percy, posted 06-15-2008 8:50 PM Percy has replied

Replies to this message:
 Message 224 by Percy, posted 06-16-2008 8:20 AM PaulK has replied

Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 224 of 451 (471347)
06-16-2008 8:20 AM
Reply to: Message 223 by PaulK
06-16-2008 7:30 AM


Insufficiently Supported Dietary Recommendations
PaulK writes:
And Taubes' ideas don't seem to be any better supported.
Yes, that's one of the important points. It's a point that both Taubes and Marantz make (though of course Taubes 450+ page book makes many more points, having a far broader scope than the 6 page Marantz paper). They both believe the current level of diet/health research is inadequate for making recommendations.
But in assessing the current state of research it should be realized that there is increasing recognition on the part of both researchers and those responsible for diet/health recommendations at the National Institutes of Health, FDA, USDA, and so forth, that the current consensus about dietary fat is looking increasingly suspect, and that the potentially significant role of carbohydrates is becoming increasingly appreciated.
You also cannot forget the list of some of the key supporting observations for the carbohydrate hypothesis that I provided in Message 215, and here it is again:
  1. The obesity epidemic has coincided with increased intake of carbohydrates.
  2. Human metabolism with respect to weight gain is nowhere near as simple as "a calorie is a calorie is a calorie," as can seen with otherwise identical people on the same diet having different weight gain experiences. Laboratory genetic experiments have duplicated this effect by producing strains of animals that are naturally fat and that get much fatter on the same diet as normal ones. There are clearly other factors at work beyond calories that are at present not well understood.
  3. Transplantation of skin from a region of fat accumulation, such as the belly, to a region where fat accumulation is rare, such as the back of the hand, sees that tissue gain weight identically to where it came from throughout the subject's lifetime.
  4. Emaciation and obesity has been observed in the same individual simultaneously. Women emaciated above the waist and obese below is one example. Clearly something related to tissue metabolism, not diet, is the significant factor.
  5. Insulin regulation plays a key role in obesity because it encourages the conversion of fatty acids into triglycerides by adipose tissue (fat tissue), and insulin levels are strongly influenced by blood glucose levels, which are in turn influenced by carbohydrate intake.
  6. The progression from normal to metabolic syndrome to diabetes type II hints that elevated carbohydrate intake has a wearing effect on body metabolism for susceptible individuals, primarily the pancreas and its production of insulin. Unfortunately, susceptible individuals represent a significant proportion of most populations.
At a bare minimum these observations indicate that current dietary recommendations regarding dietary fat and carbohydrates are flawed, and that there is much we don't understand about body metabolism. And Taubes presents a great deal of evidence in his book that the interplay between various body hormones, most significantly insulin, has a great deal to do with obesity.
Given that subsistence farmers have survived generations on high-carb diets it seems that these "more serious" questions are easily answered in exactly the same way.
I'm not familiar with any such studies, but subsistence usually means physically demanding and that dietary intake is just sufficient to survive. A diet meager in quantity, even if high in the proportion of carbohydrates, and combined with rigorous physical activity cannot produce obesity.
But I'm not endorsing a carbohydrate-free diet. No one is. I was simply noting that when it comes to the three sources of calories, protein, fat and carbohydrates, only protein and fat are essential.
The larger point is getting lost in detail. Taubes argues that the dietary fat hypothesis is not very well supported by the available evidence, and he presents a lot of evidence that the carbohydrate hypothesis is a better fit. But he also points out that the research is insufficient to reach a conclusion in either direction, and he concludes his book with a plea for more research.
--Percy
Edited by Percy, : Change title.

This message is a reply to:
 Message 223 by PaulK, posted 06-16-2008 7:30 AM PaulK has replied

Replies to this message:
 Message 225 by PaulK, posted 06-16-2008 1:58 PM Percy has replied
 Message 226 by Joe T, posted 06-16-2008 4:25 PM Percy has replied

PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 225 of 451 (471388)
06-16-2008 1:58 PM
Reply to: Message 224 by Percy
06-16-2008 8:20 AM


Re: Insufficiently Supported Dietary Recommendations
quote:
You also cannot forget the list of some of the key supporting observations for the carbohydrate hypothesis that I provided in Message 215, and here it is again:
Lets go through them
quote:
1. The obesity epidemic has coincided with increased intake of carbohydrates.
This would be significant (although far from conclusive) if calorie intake had remained the same, with fats replaced by carbohydrates. However, Marantz et al point out that calorie intake increased, with fat consumption remaining about the same in absolute terms.
(It may also be notable that obesity in women seems to have increased more steeply, and women are eating more fat, not less).
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2. Human metabolism with respect to weight gain is nowhere near as simple as "a calorie is a calorie is a calorie," as can seen with otherwise identical people on the same diet having different weight gain experiences. Laboratory genetic experiments have duplicated this effect by producing strains of animals that are naturally fat and that get much fatter on the same diet as normal ones. There are clearly other factors at work beyond calories that are at present not well understood.
"A calorie is a calorie" is not about individual differences. THe most you can hope to argue there is that individuals react differently to different sources of calories. But that would undermine Taubes' claims about carbohydrates, too.
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3. Transplantation of skin from a region of fat accumulation, such as the belly, to a region where fat accumulation is rare, such as the back of the hand, sees that tissue gain weight identically to where it came from throughout the subject's lifetime.
4. Emaciation and obesity has been observed in the same individual simultaneously. Women emaciated above the waist and obese below is one example. Clearly something related to tissue metabolism, not diet, is the significant factor.
These also seem to undermine Taubes' claims about carbohydrates since they deny a link to diet.
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5. Insulin regulation plays a key role in obesity because it encourages the conversion of fatty acids into triglycerides by adipose tissue (fat tissue), and insulin levels are strongly influenced by blood glucose levels, which are in turn influenced by carbohydrate intake.
6. The progression from normal to metabolic syndrome to diabetes type II hints that elevated carbohydrate intake has a wearing effect on body metabolism for susceptible individuals, primarily the pancreas and its production of insulin. Unfortunately, susceptible individuals represent a significant proportion of most populations.
I don't know enough to discuss these points in detail. However they appear too simple to be relied on. If we don't know enough about metabolism to judge then we don't know enough to judge those.
So. You have one argument which we already know is based on inadequate information (as I pointed out long ago). Three which seem to count against Taubes' view as much as any other. And two which are maybes, but I don't feel competent to confidently judge. That really isn't very good out of six.
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I'm not familiar with any such studies, but subsistence usually means physically demanding and that dietary intake is just sufficient to survive. A diet meager in quantity, even if high in the proportion of carbohydrates, and combined with rigorous physical activity cannot produce obesity.
In case you didn't notice, Percy I just mirrored your argument. You didn't refer to studies or take lifestyle into account (or even the details of the traditional Inuit diet).
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But I'm not endorsing a carbohydrate-free diet. No one is.
That isn't how I read this statement from Message 220. I'd say that it is quite clearly stating that the best diet has no carbohydrates:
The very complex carbohydrates in starchy foods are preferable to the very simple carbohydrates in sugar. No carbohydrates are even better.
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Taubes argues that the dietary fat hypothesis is not very well supported by the available evidence, and he presents a lot of evidence that the carbohydrate hypothesis is a better fit.
I've got no quarrels with the first point. But the second seems to be very questionable. Aside from the biochemistry arguments (which Molbiogirl disputed - and she likely knows better than either of us) the arguments seem to be very poor, and even inconsistent.

This message is a reply to:
 Message 224 by Percy, posted 06-16-2008 8:20 AM Percy has replied

Replies to this message:
 Message 228 by Percy, posted 06-16-2008 11:27 PM PaulK has replied
 Message 253 by molbiogirl, posted 07-04-2008 12:06 AM PaulK has not replied

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