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Author Topic:   Good Calories, Bad Calories, by Gary Taubes
Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 1 of 451 (463453)
04-17-2008 11:22 AM


Gary Taubes' Good Calories, Bad Calories challenges conventional thinking about the effect of diet on health. He argues that dietary fat has been falsely implicated as the primary cause of the western life-style diseases of heart disease, diabetes and obesity, and that the actual cause is refined carbohydrates such as bread, pasta, and worst of all, refined sugar.

He makes a strong argument, but he's only a science writer, not a scientist. He was interviewed this past December on the The Skeptics Guide to the Universe podcast, and the audience responses read during the following week's podcast were largely critical, generally saying that science writers should communicate scientists' opinions, not their own.

I've also read Taubes' book Cold Fusion chronicling the cold fusion fiasco, and I've read a number of his articles in science magazines, and I've come to have a great deal of respect not only for his writing but also for his opinions, and so I treat his opinions about diet very seriously. They seem to make a lot of sense.

--Percy


Replies to this message:
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Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 2 of 451 (464704)
04-28-2008 1:33 PM


Why Most Modern Diet Advice is Wrong
The premise of Good Calories, Bad Calories is that most modern diet advice is wrong, and it supports this premise by exploring the relevant research and showing that it really doesn't support the advice. But if that's the case, then how come it is always claimed that this advice is supported by evidence. Good question.

It appears that some very appealing hypotheses, appealing because the very facts of reality itself argue that they must be true, have interfered with the scientific process. These hypotheses are:

  • Eating too much makes you fat (more accurately, the claim is that you will gain weight if you consume more calories than you burn).

  • Exercising is an effective approach to weight reduction.

  • Too much fat in the diet makes you fat.

The research actually supports none of these, so how can health professionals claim that they do? The answer is that these hypotheses are so appealing and seem so obvious that most research has been interpreted under the assumption that these are true.

The facts of the matter appear to be:

  • The body has a desired weight (how it selects that weight is unknown) that it will maintain by regulating the impulse for hunger and the desire for physical activity. This is why almost all diets fail.

  • If you eat less, you will become less active and maintain your weight.

  • If you exercise more, your appetite will increase, you will eat more, and you will maintain your weight.

  • Too much fat in the diet is not what makes you fat. Fat is actually good for you, including saturated fats. It is too much intake of carbohydrates, particularly refined carbohydrates in sugar, candy, soda, bread and pasta, that makes you fat.

I haven't quite finished the book yet, but this seems very much to be where Taubes is going. Bottom line: if you want to lose weight, cut way down on the carbohydrates.

--Percy


Replies to this message:
 Message 3 by Jazzns, posted 04-28-2008 5:24 PM Percy has replied
 Message 180 by Hyroglyphx, posted 06-07-2008 5:25 PM Percy has seen this message

Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 4 of 451 (464730)
04-28-2008 8:21 PM
Reply to: Message 3 by Jazzns
04-28-2008 5:24 PM


Re: Why Most Modern Diet Advice is Wrong
Much of what you say echos the book, and except for the popcorn much of what you say is consistent with my own experience.

I've been paying attention only to the carbohydrate/sugar portions of the nutrition labels, and that's been working pretty well, with one possible exception. It's too soon for me to reach any firm conclusions, but I suspect meat snacks (beef jerky genre) and cold cuts (ham, salami, roast beef, etc) of being fattening somehow, even though they contain little to no carbohydrates or sugars. What's been your experience?

About soda, I drink very little soda, usually only when we go out to lunch from work, but I've switched to diet soda to eliminate the refined sugar (I assume it would usually be 55% glucose and 45% fructose).

I don't care about candy or alcohol (usually), I just can't stand being hungry. My ability to overcome hunger with willpower has declined with age.

--Percy


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 Message 3 by Jazzns, posted 04-28-2008 5:24 PM Jazzns has replied

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Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 6 of 451 (464806)
04-29-2008 1:47 PM


Balanced Diets are Bunk
I didn't actually intend this book thread to be a diet discussion, though I'm more than happy to discuss diet recommendations and experiences, too. The main issue is how could the health community have gone so wrong when it comes to diet advice. Why, for example, does the American Heart Association insist that very low carbohydrate diets are "fad diets" worthy of no more consideration than the grapefruit diet or the ice cream diet?

Last night I read another key section of the book, this time about the research supporting the dietary recommendation that we should eat plentifully from all the major food groups in order to insure proper health and nutrition. The research does not support this claim. It is another claim that is made simply because it makes so much sense. For example, studies in the first half of the 20th century revealed the importance of various vitamins and minerals to health, and their presence in fruits and vegetables led to recommendations that these were necessary to health. But many human populations throughout history have had little to no fruits or vegetables in their diet, and they not only survived but thrived.

It is possible, even likely, that the importance of a balanced diet is a myth perpetrated by well-meaning officials in governmental positions of responsibility regarding the health of the country (e.g., the Surgeon General, top officials at the National Institutes of Health, etc.), by the food industry, by the supplement industry, and by diligent researchers who allow underlying (and false) assumptions about dietary influences to affect their assessments of evidence.

I've long believed that the conventional wisdom about balanced diets was wrong, so naturally I'm very receptive to Taubes' conclusions, but the argument makes a lot of sense. The diets of most animals are very unbalanced, and I'm sure this has also been true for humans throughout our evolutionary history, including right up the present for isolated primitive societies. For example, Eskimo diets are almost exclusively meat.

The fact of the matter is that teasing out the influences of individual dietary contributions is exceedingly difficult. For example, in the case of heart disease the conclusion that increased intake of fat is associated with increased rates of heart disease is a very, very mild correlation, but in the aggregate across an entire country the size of America heart disease affects a huge number of individuals, and so government officials responsible for health feel it imperative to provide advice. But the actual effect is of an order less than 1%, and this effect is so tiny in any individual, it means that despite all the research into cholesterol, HDLs, LDLs, VLDLs, triglycerides, saturated fats, polyunsaturated fats, monounsaturated fats, etc., etc., researchers still haven't identified any mechanism by which increased fat intake increases the risk of heart disease.

Ironically, considering the American Heart Associations stance on carbohydrates, you know what correlates with heart disease far better than fat intake? Obesity. And you know what is the most likely cause of obesity? Carbohydrates. In effect, the American Heart Association's dietary recommendations increase the risk of heart disease. Go figure.

Also ironically, fat is good for you. Mortality is higher with low fat intake than with high fat intake. Specifically, the mortality rate from cancer is higher with low fat diets than the mortality rate from heart disease with high fat diets. Choose your poison, and remember, the effect is so tiny, the possibility that you're doing yourself any measurable good by modifying your fat intake is minuscule. Eat butter, drink whole milk, eat lots of meat and cut the carbs. Fat is good, while carbs, especially the refined carbohydrates found in sugar, soda, bread and pasta, are bad. Very bad.

--Percy


Replies to this message:
 Message 7 by Jazzns, posted 04-29-2008 2:09 PM Percy has replied
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Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 8 of 451 (464862)
04-30-2008 11:25 AM
Reply to: Message 7 by Jazzns
04-29-2008 2:09 PM


Re: Balanced Diets are Bunk
Jazzns writes:

I would look into the thing about carbs. There is nothing wrong with carbs and in fact some of the things I personally eat are very high in carbs. They just also happen to be very high in fiber which is a net bonus. They give me energy, fill me up, keep me regular, and are hopefully staving off lipid diseases later in life.

Just so people don't get the wrong idea, I think what you're saying is that the carbohydrates you personally eat happen to be in food that is very high in fiber, not that carbohydrates themselves are high in fiber. Refined sugar, for example, like that found in candy and soda, has 0 grams fiber.

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.

Cholesterol is the big bugaboo of heart disease, but it has legitimate positive roles in metabolism, so the LDLs circulate throughout the body gradually delivering their cholesterol until there is little or none left, at which time they become small, dense LDLs that have a severe deleterious and wide-ranging impact that can best be summed up as accelerating the aging process.

The proportion of small, dense LDLs in the bloodstream is a function of the how severely and frequently you spike your blood sugar through the intake of refined carbohydrates.

The bottom line is that if you're happy with your weight, don't worry about carbohydrate intake, but definitely try to avoid rapid consumption of refined carbohydrates. This means that unless you're willing to consume them very slowly, don't drink sugared soda, don't eat candy, don't eat sugared breakfast cereals, don't eat bread, don't eat pasta. They're unhealthy.

And if you're not happy with your weight, then reduce your carbohydrate intake to less than 100 grams/day, better is under 70 grams/day, though I personally find that hard to do. There is a bit of monotony to low carbohydrate diets.

--Percy

Edited by Percy, : Spelling.


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 Message 9 by molbiogirl, posted 04-30-2008 11:38 AM Percy has replied

Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 11 of 451 (464943)
05-01-2008 8:41 AM
Reply to: Message 9 by molbiogirl
04-30-2008 11:38 AM


Re: Balanced Diets are Bunk
In this particular case the book provides authors and years, not titles, but there may be enough information to track a few papers down for you. Internet's down at home right now, very bad timing for other reasons, so this'll have to wait a day or two. I knew I should have kept the DSL for backup.

--Percy


This message is a reply to:
 Message 9 by molbiogirl, posted 04-30-2008 11:38 AM molbiogirl has replied

Replies to this message:
 Message 12 by molbiogirl, posted 05-01-2008 9:45 AM Percy has replied
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Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 13 of 451 (464951)
05-01-2008 10:09 AM
Reply to: Message 12 by molbiogirl
05-01-2008 9:45 AM


Re: Balanced Diets are Bunk
molbiogirl writes:

For what it's worth, my off the cuff impression is that assuming carbs with a high glycemic index are inherently bad (and lead to obesity and CHD) is overstating the case in the extreme.

Glycemic index can be a very misleading measure of the goodness/badness of carbohydrates. For example, table sugar has a relatively low glycemic index compared to other carbohydrate sources because it is 50% fructose, which isn't included in the glycemic index. Fructose is metabolized via a different route than glucose (the other 50% of table sugar) but still carries with it considerable health risks.

Japanese folks eats loads of high GI food (rice) and yet they have very low rates of obesity and CHD.

This is the most commonly cited evidence against the carbohydrate hypothesis, but the details of the actual research do not exclude the possibility of carbohydrates as a significant factor in obesity, diabetes and heart disease. Even if they did, considering the wealth of other evidence, the Japanese experience would merely be an unexplained anomaly.

The validity of the book's claims can be assessed in a more general and less scientific way, but still exceptionally enlightening. Whatever one might believe science demonstrates to be the case, reality is that while western countries have increasingly focused on fat as the cause of obesity and heart disease (just check the number of products touting "low fat" on grocery store shelves or the amount of shelf space in the meat department dedicated to lean meat, a result of following recommendations from agencies like the American Heart Association, the National Institutes of Health and the AMA), the incidence rates for these diseases of western civilization have increased. The only component of the diet that has increased significantly over this period is carbohydrates.

--Percy


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 Message 12 by molbiogirl, posted 05-01-2008 9:45 AM molbiogirl has replied

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 Message 15 by molbiogirl, posted 05-01-2008 10:39 AM Percy has replied

Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 16 of 451 (465096)
05-02-2008 11:23 PM
Reply to: Message 9 by molbiogirl
04-30-2008 11:38 AM


Re: Balanced Diets are Bunk
molbiogirl writes:

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.

Percy, can you peek at the cites at the back of the book and find a couple of papers I can look up re: this point?

Sure. The original researcher in this area was Ronald Krauss, here's one of the first papers:

Identification of multiple subclasses of plasma low density lipoproteins in normal humans. Ronald M. Krauss and David J. Burke. Journal of Lipid Research, Vol 23, 970194, January, 1982.

Here's a more recent one:

Properties of triglyceride-rich and cholesterol-rich lipoproteins in the remnant-like particle fraction of human blood plasma. Elisa Campos, Leila Kotite, Patricia Blanche, Yasushi Mitsugi, Philip H. Frost, Umesh Masharani, Ronald M. Krauss, and Richard J. Havel. Journal of Lipid Research, Vol 43, 365-374, March, 2002.

I have a feeling that individual papers aren't going to tell the whole story as the process is fairly complicated and probably took time to tease out.

Why are you asking, by the way? Is there something controversial about that characterization of the liver's response to elevated blood sugar levels?

--Percy


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 Message 9 by molbiogirl, posted 04-30-2008 11:38 AM molbiogirl has replied

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 Message 18 by molbiogirl, posted 05-03-2008 1:15 AM Percy has replied

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 17 of 451 (465097)
05-02-2008 11:44 PM
Reply to: Message 15 by molbiogirl
05-01-2008 10:39 AM


Re: Balanced Diets are Bunk
molbiogirl writes:

Stating categorically that refined carbs are very, very bad is just as deceptive as stating categorically that fats are very, very bad.

The problem with refined carbohydrates is that they're rapidly digested and cause blood sugar spikes, which in turn cause an insulin response from the pancreas, which in turn causes the liver to produce LDLs with a high payload of cholesterol. The eventual destiny of these LDLs is to give up their cholestrol and end up as small, dense LDLs which have a greatly heightened ability to leave deposits on blood vessel walls, and they have a deleterious effect generally on cell metabolism.

The cause of obesity is levels of insulin in combination with other hormones and a person's individual metabolism sufficient to encourage fat cells to emphasize the fatty acid=>triglyceride process, rather than the reverse triglyceride=>fatty acid process. Triglyerides are stored in the fat cells for later use as energy. Significantly, this process of storage of triglycerides in fat cells in the presence of insulin will take place at the expense of other demands of the body for energy, for example, hunger and exercise. And most importantly, the presence of fatty acids by themselves is insufficient to cause their net conversion into triglycerides - that takes insulin, whose levels are driven by blood sugar levels, whose levels are in turn driven by carbohydrate intake.

Glycemic index can be a very misleading measure of the goodness/badness of carbohydrates.

Then how does one distinguish between good and bad?

I don't really know. I was only pointing out that the glycemic index is very misleading. Whatever the right way is of "distinguishing between good and bad," that isn't it. Perhaps the presence of fiber is a better determinate of the goodness/badness of carbohydrates.

--Percy


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 Message 15 by molbiogirl, posted 05-01-2008 10:39 AM molbiogirl has replied

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Percy
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Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 20 of 451 (465117)
05-03-2008 8:42 AM
Reply to: Message 18 by molbiogirl
05-03-2008 1:15 AM


Re: Balanced Diets are Bunk
molbiogirl writes:

Neither of your cites has anything to do with insulin.

You didn't ask about insulin. This was your original question in Message 9:

molbiogirl in Message 9 writes:

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.

Percy, can you peek at the cites at the back of the book and find a couple of papers I can look up re: this point?

Your inquiry didn't mention insulin, so there should be no surprise that the papers I provided don't mention insulin.

So I guess the real issue is that your questioning this assertion:

Because you (and the author) claim that insulin levels are related to elevated LDL levels.

I don't understand why this is controversial, either. Just a simple Google reveals this in Wikipedia's article on LDL's:

Wikipedia writes:

Dietary Insulin induces HMG-CoA reductase activity, whereas glucagon downregulates it. [7]

I've not heard of "HMG-CoA reductase", but apparently it encourages the production of LDL's.

(VLDL = the small, dense LDLs you mention).

In my early reading I thought this was true myself, but I was never able to establish that this was actually the case, and Wikipedia seems to agree that they are distinct entities, e.g. from the same article:

Wikipedia writes:

LDL is formed as VLDL lipoproteins lose triglyceride through the action of lipoprotein lipase (LPL) and become smaller and denser, containing a higher proportion of cholesterol.

So if LDL is formed from VLDL, VLDL shouldn't really be considered one of the sub-forms of LDL. But maybe it is thought of that way in some circles. There's a degree of ambiguity concerning this in what I've read so far.

But if VLDL is actually small, dense LDLs as you claim, then I think you believe I'm in effect claiming that insulin encourages VLDL synthesis, because you say this:

I have also found plenty of evidence that insulin suppresses VLDL synthesis

But I'm not sure VLDL and small, dense LDLs and the same thing, so I'm not sure I'm making the claim you think I am. I just don't know.

No consensus has been obtained for the notion that hyperinsulemia or insulin resistance contributes significantly to the risk of coronary heart disease (CHD) similarly to major risk factors, high total and LDL cholesterol, elevated blood pressure, smoking, low HDL cholesterol, diabetes and aging.

Metabolic Syndrome in the 21st Century, Jose Antonio Gutierrez, 2005.

One of the complaints in the book is that health research has become specialized to the point where there is little exchange of information between the various disciplines, and one of the many regrettable effects is a lack of consensus, so Taubes certainly agrees that there is no consensus. But he presents the evidence that supports a connection between hyperinsulemia and heart disease.

I'd be happy with a paper that gives me just a piece of the puzzle. Something that looks at insulin and LDL levels, for example.

I'm not a health researcher and would prefer to debate on the basis of arguments offered here about the processes involved, with references to papers provided only for reinforcement, which is what the Forum Guidelines attempt to encourage (see rules 4 and 5). For example, you cite four papers in support of your position but offer no argument in your own words. If you describe what you think is really happening in the body then I'll have something more concrete to go on.

--Percy


This message is a reply to:
 Message 18 by molbiogirl, posted 05-03-2008 1:15 AM molbiogirl has replied

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 Message 22 by molbiogirl, posted 05-03-2008 3:28 PM Percy has replied

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 21 of 451 (465127)
05-03-2008 11:02 AM


MSG and Obesity
As one might imagine, I've been playing with applying the lessons of Good Calories, Bad Calories by reducing my intake of carbohydrates. I attempt to keep it below 100 grams/day, and I'm probably somewhere in that ballpark.

One of the problems with traditional diets is hunger. As any obesity researcher who accepts the conventional wisdom that obesity is caused by consuming more calories than are used will tell you, diets don't work, primarily because very few can endure hunger for lengthy periods without surrendering to it, and this has been my own experience.

One of the seemingly contradictory qualities of a low carbohydrate diet is that one does not get hungry on it, even when eating very little (it's 10:30 AM, I haven't had breakfast yet because I'm simply not hungry), but I didn't know that going in, so once I decided to reduce my carbohydrate intake, I immediately set out to address the problem of what to snack on to alleviate what I thought would be the inevitable hunger pangs. I hit upon meat snacks, generally very low in carbohydrates and sugar.

Naturally since I was following no diet book the structure of my diet took a while to form itself, and in the early stages I was consuming more vegetables and less meat than I am now, and I was less aware of the carbohydrate contributions of some foods, like sweet pickles that had been a common resort when I needed to hold off hunger. I was also less strict about staying away from rice and potatoes.

What I found was that even small amounts of rice and potatoes are fatal to the diet, and that you have to be careful with some vegetables (still learning which ones), especially starchy vegetables or those low in fiber. I think younger people wouldn't have to be so strict, but the weight is harder to hold off as you grow older.

But it was the meat snacks that gave me the greatest surprise. Despite the low carbohydrate/sugar content on the labels, it quickly became evident that consuming meat snacks was counterproductive. But why?

I had set the meat snacks aside for a while, but a few days ago I had a few (well, it might have been more than a few), and within an hour I was suffering all the effects of MSG that I'm so familiar with.

For me, MSG ingestion is experienced as physical fatigue, drowsiness and brain fogginess. It's unmistakable. I immediately checked the meat snack labels for MSG and found it listed on one of the five. But that one meat snack all by itself, even if full of MSG, would be unlikely to cause such a strong effect, so I began investigating MSG and found that it's a sodium salt of glutamate (hence the name, monosodium glutamate), and that it's the glutamate that is the active element in body metabolism.

Glutamate can find it's way into our diet through more than just MSG, because it is a very common additive that appears in a number of different forms, such as hydrolyzed vegetable proteins and yeast extract, and it can be hidden under completely generic names like "spices" and "natural flavorings". Checking the other meat labels for these kinds of ingredients, I found:

  • Hydrolized soy corn
  • Hydrolized corn protein
  • Hydrolized corn and soy protein
  • Spices and flavorings
  • Flavorings

So potentially the meat snacks I had just consumed contained significant levels of glutamate. But why would glutamate cause physical fatigue, drowsiness and brain fogginess?

One way would be if glutamate caused insulin levels to increase. Insulin would trigger the fat cells to increase their uptake of fatty acids to store them as triglycerides, making less energy available for body metabolism and causing all the symptoms.

But does glutamate cause elevated insulin levels. There isn't much about this on the Internet, but I did find one study: Glutamate ingestion: the plasma and muscle free amino acid pools of resting humans. It found that 150 mg/kg of MSG caused a threefold increase in insulin levels after 15 minutes.

So if MSG elevates insulin levels, then MSG is another factor in obesity.

One obvious question is why I had not experienced the MSG response before this, since this wasn't the first time I had eaten the meat snacks. The answer is that I had always consumed them just before going to bed, and so wouldn't notice the MSG effects as I fall asleep very quickly, and the MSG would only aid the process. But this time my Internet was out and I was waiting for the Internet service person in the middle of the afternoon.

So no more meat snacks, and my favorite sausage patty also lists MSG, so I'm debating that one. But I'm wondering if anyone out there has more information about glutamates in foods and their effects on body metabolism.

--Percy


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 Message 26 by molbiogirl, posted 05-04-2008 5:50 AM Percy has replied

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 23 of 451 (465175)
05-03-2008 8:41 PM
Reply to: Message 22 by molbiogirl
05-03-2008 3:28 PM


Re: Balanced Diets are Bunk
molbiogirl writes:

I thought it was clear that my question concerned the link between insulin and LDL/CHD.

Check the message links. I was responding to your inquiry in Message 9, which preceded the first mention of insulin in the thread.

Taubes agrees with you that VLDL is a precursor of LDL, this is from page 175:

Taubes writes:

As for secretion, the key point is that most low-density lipoproteins, LDL, begin their lives as very low-density lipoproteins, VLDL. (This was one implication of the observation that both LDL and VLDL are composed of the same apo B protein, and it was established beyond reasonable doubt in the 1970s.) This is why VLDL is now commonly referred to as a precursor of LDL, and LDL as a remnant of VLDL.

But you're right that I explained it incorrectly. What Taubes is actually saying is that blood sugar spikes encourage the liver to temporarily store fatty acids away as triglycerides, and these are later released into the bloodstream as VLDLs.

If you're saying that the release of VLDLs doesn't occur while insulin levels are high, this is certainly consistent with Taubes' description as he isn't specific on this point. What he does say is that once triglycerides are stored in the liver that their release is inevitable. The more often you spike your blood sugar, the more often the liver will sock away triglycerides, and the more VLDLs the liver will eventually produce.

What insulin does do more directly is influence fat cells to tilt the balance of conversion back and forth between fatty acids and triglycerides toward the production of triglycerides, which means you get fatter independent of any energy demands from the body in terms of hunger or exercise. In other words, even if you're starving, or even if you're in the middle of 5 set tennis match under a hot sun, if you elevate your insulin levels then fat cells will steal from the rest of the body by gobbling up the available fatty acids that other cells (muscle cells, for example) might use for energy.

Probably Taubes' most important point is that the conventional wisdom about obesity, that it is a simple result of too many calories in and too few calories out, that the obese simply eat too much and exercise too little, is wrong. Exercise, hunger and fat storage are not independent variables. If you exercise more you'll eat more. If you eat less you'll exercise less. The willpower necessary to overcome this reality is in limited supply for most people.

--Percy


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 Message 22 by molbiogirl, posted 05-03-2008 3:28 PM molbiogirl has replied

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 Message 24 by molbiogirl, posted 05-03-2008 10:17 PM Percy has replied

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 27 of 451 (465236)
05-04-2008 9:11 AM
Reply to: Message 24 by molbiogirl
05-03-2008 10:17 PM


Re: Balanced Diets are Bunk
molbiogirl writes:

First. Glucose is stored in the liver as glycogen, not triglycerides. Glycogen is a complex carbohydrate. A triglyceride is a fat, formed from three fatty-acid molecules and one glycerol molecule. Triglycerides are stored in adipose tissue.

It might be best to quote Taubes again. This is from page 175 again:

Taubes writes:

After we eat a carbohydrate-rich meal, 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. These triglycerides are no more than droplets of oil. In the liver, the oil droplets are fused to the apo B protein and to the cholesterol that forms the outer membrane of the balloon. The triglycerides constitute the cargo that the lipo-proteins drop off at tissues throughout the body. The combination of cholesterol and apo B is the delivery vehicle. The resulting lipoprotein has a very low density and so is a VLDL particle, because the triglycerides are lighter than either the cholesterol of the apo B. For this reason, the larger the initial oil droplet, the more triglycerides packaged in the lipoprotein, the lower its density.

So you're disputing that the liver converts glucose into triglycerides, so we can look into that. Do you agree with the other portions of the described process, i.e., that the liver does store triglycerides that are later released as VLDLs? In other words, is it just the production of triglycerides from "some glucose" that you dispute, or the entire process?

Third. Blood sugar spikes don't "encourage" anything but an insulin response. If you have evidence to the contrary, I would be interested in hearing it.

Taubes says, "After we eat a carbohydrate-rich meal, 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." He appears to be saying that the presence of a great deal of glucose influences the liver to use some of it for triglyceride production and storage. In conjunction with your earlier point, you seem to not only disagree that the liver creates triglycerides from glucose, but that that point aside, blood sugar spikes don't cause any response anywhere except the pancreas, which produces insulin.

Fourth. The release of glycogen as VLDL is not "inevitable". Glycogen is released from the liver as glucose, not VLDL.

This is one point that I didn't manage to garble. Both mine and Taubes' descriptions said that triglycerides, not glycogen, are released in VLDL.

Fifth. FFAs are released from adipose tissue (fat), not the liver.

This is another point upon which both I and Taubes were clear. Neither of us said that free fatty acids are released from the liver.

Sixth. FFAs are packaged into VLDL by the liver ... from blood plasma FFAs derived from dietary fat, not carbohydrates.

Taubes says that it is triglycerides that are packaged into VLDL, not FFAs. I'm poking around in Wikipedia trying to understand this stuff better, and in the Wikipedia article on triglycerides it says, "Fat and liver cells can synthesize and store triglycerides."

So I presume that the formation of triglycerides in the liver is not controversial, so I guess what you're disputing is that it is actually FFAs that are packaged into VLDLs, not triglycerides. But the same Wikipedia article also says, "Triglycerides, as major components of very low density lipoprotein (VLDL) and chylomicrons, play an important role in metabolism as energy sources and transporters of dietary fat."

Did you really mean to say FFAs? Did you instead mean trigylcerides (for any lurkers, triglycerides are formed from binding together three FFAs (Free Fatty Acids))?

As far as I can see, the description about the liver, insulin and glucagon that you took from GLYCOGEN, GLUCONEOGENESIS, FATTY ACID METABOLISM AND HORMONAL CONTROL OF LIPID AND CARBOHYDRATE METABOLISM is orthogonal to the discussion. If there's a relationship between this and our discussion about the production of VLDL by the liver it is not apparent to me.

I took a look at your diagram, here it is again for reference:


Click to enlarge

The top box in the diagram labeled "Liver" seems consistent with Taubes description of glucose having a role in the production of VLDL. While it doesn't describe the fatty acids as triglycerides, it doesn't describe them as free fatty acids, either, so since the diagram isn't specific on this point it is again consistent with Taubes description, and if Wikipedia is correct, the liver can synthesize and store triglycerides.

What insulin does do more directly is influence fat cells to tilt the balance of conversion back and forth between fatty acids and triglycerides toward the production of triglycerides...

Elevated TG levels are correlated to insulin resistance, not normal insulin response. In other words, hyperinsulemia is correlated to elevated TGs, not blood sugar spikes. And, as I said before, the causes of hyperinsulemia are probably genetic, not behavioral (aka carb intake).

Are you talking about elevated TG levels in the bloodstream? I don't believe Taubes makes any claims about insulin's influence on triglyceride levels in the bloodstream, and if he does then I missed them. I certainly wasn't trying to say anything about insulin's influence on TG levels in the bloodstream.

What I was saying, in shorthand form since I had said the same thing at greater length and with more clarity in prior posts, is that insulin influences fat cells to tilt the balance of their continual conversion back and forth between FFAs and triglycerides toward the FFA=>triglyceride process, resulting in the fat cell making a net drain upon FFAs in the bloodstream.

When under stress from starvation, the body uses protein and fat as energy. Because no glucose is available.

You can prove to yourself that the absence of intake of glucose in the form of carbohydrates isn't stress or starvation with a simple personal experiment: Eat only meat for an entire week.

When under stress from overexertion, the body uses glycogen stores in the liver. That's just plain old glucose.

The body can draw upon glucose, fatty acids and protein for energy. In the absence of insulin the fat cells in the body will tilt the balance of the FFA/triglyceride conversion process toward the production of FFAs which are released into the bloodstream for use as energy.

Later today I'll be playing tennis for a couple hours and will be experiencing no physical duress after having consumed less than 100 grams/day of carbohydrates for the past few weeks.

Fat cells (adipose tissue) don't "steal" anything from anywhere. They are storage depots. That is all.

In the presence of insulin, fat cells are a net drain upon fatty acids in the blood stream as they convert it to stored triglycerides.

Probably Taubes' most important point is that the conventional wisdom about obesity, that it is a simple result of too many calories in and too few calories out, that the obese simply eat too much and exercise too little, is wrong.

I have yet to see any evidence of that.

So in light of the national experience over the past century with obesity, diabetes and heart disease, how's your theory that it's primarily due to dietary fat working out for you?

--Percy


This message is a reply to:
 Message 24 by molbiogirl, posted 05-03-2008 10:17 PM molbiogirl has replied

Replies to this message:
 Message 30 by molbiogirl, posted 05-04-2008 2:53 PM Percy has replied

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 28 of 451 (465238)
05-04-2008 9:36 AM
Reply to: Message 25 by molbiogirl
05-04-2008 5:25 AM


Re: NYT review
Hi Molbiogirl,

I'm not going to debate a book review. If you'd like to state your objections in your own words I'd be glad to address them, as I have been. But I will say a couple things about the book review.

Taubes' book is lengthy and detailed, but even a book of 10,000 pages couldn't mention everything, so criticizing it because "it can be hard to know what has been left out" is a criticism without merit because it can be leveled at literally anything written.

Along the same lines, criticizing Taubes for not mentioning a specific series of studies by Jules Hirsch in the 1950s and '60's when Taubes mentions Hirsch and his views (very antagonistic toward the carbohydrate hypothesis, of course) copiously throughout the book is pretty misleading. Taubes' index for "Hirsch, Jules" lists these pages: 245-6, 256-7, 270-1, 282, 299, 398, 415, 420-1, 422. He by no means ignores Hirsch or his views.

I'm afraid that your description involving insulin signaling was so sketchy, really non-existent being primarily just a diagram and a list of processes, that I can't tell what point you were trying to make.

--Percy


This message is a reply to:
 Message 25 by molbiogirl, posted 05-04-2008 5:25 AM molbiogirl has taken no action

Percy
Member
Posts: 20838
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.6


Message 29 of 451 (465240)
05-04-2008 9:44 AM
Reply to: Message 26 by molbiogirl
05-04-2008 5:50 AM


Re: MSG and Obesity
Thanks for the information and research suggestions, but I'm just a layperson in this area. I don't think I could muster the time, and certainly not the expertise, to understand this area at the same level of detail as the researchers.

I understand that glutamate is a key part of many metabolic processes, and I know there is widespread doubt in the research community that MSG reactions are real, but something significant is definitely going on. I'm willing to accept any number of explanations, but "it's all in your imagination" is not one of them.

--Percy

Edited by Percy, : Grammar.

Edited by Percy, : Grammar again.


This message is a reply to:
 Message 26 by molbiogirl, posted 05-04-2008 5:50 AM molbiogirl has taken no action

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