The definitive study on dietary fat and weight

Discussion in 'Food and nutrition' started by [email protected] (Larry Weisenthal), Jan 4, 2006.

  1. Juhana Harju

    Juhana Harju Guest

    [email protected] wrote:

    : Comments: The "low fat" diet was 27% calories as fat. Hardly low fat.
    : Carbohydrate quality wasn't controlled. The diets were isocaloric (ie.
    : controlled and forced feeding) and not ad libitum. All successful
    : diabetes prevention studies have been based on fat restriction and not
    : carbohydrate restriction. Postprandial blood sugars were
    : significantly lower in the prospective, randomized study previously
    : quoted on insulin resistant women when they ate 49% carbohydrates
    : than when they ate 11% carbohydrates. Postprandial triglycerides
    : (probably more important than fasting, though seldom measured) are
    : higher on higher fat diets.
    :
    : - -
    : - Larry W

    It would be interesting to hear your comment on what Willett says in one
    interview by Frontline TV:

    "[Q:] If you're American and overweight, won't you be put on a low-fat diet?

    [Willett:] If you're overweight and living in the United States, and you go
    to a hospital and see a dietician, almost for sure, you're going to be put
    on a low-fat, high-carbohydrate diet.

    [Q:] What's your view of that?

    [Willett:] The problem is that that's really the wrong diet for an
    overweight person. Because the person is overweight, in general they're
    going to have quite a bit more insulin resistance and much less well able to
    tolerate low-fat, high-carbohydrate diet."

    http://www.pbs.org/wgbh/pages/frontline/shows/diet/interviews/willett.html

    --
    Juhana
     


  2. TC

    TC Guest

    Juhana Harju wrote:
    > [email protected] wrote:
    >
    > : Comments: The "low fat" diet was 27% calories as fat. Hardly low fat.
    > : Carbohydrate quality wasn't controlled. The diets were isocaloric (ie.
    > : controlled and forced feeding) and not ad libitum. All successful
    > : diabetes prevention studies have been based on fat restriction and not
    > : carbohydrate restriction. Postprandial blood sugars were
    > : significantly lower in the prospective, randomized study previously
    > : quoted on insulin resistant women when they ate 49% carbohydrates
    > : than when they ate 11% carbohydrates. Postprandial triglycerides
    > : (probably more important than fasting, though seldom measured) are
    > : higher on higher fat diets.
    > :
    > : - -
    > : - Larry W
    >
    > It would be interesting to hear your comment on what Willett says in one
    > interview by Frontline TV:
    >
    > "[Q:] If you're American and overweight, won't you be put on a low-fat diet?
    >
    > [Willett:] If you're overweight and living in the United States, and you go
    > to a hospital and see a dietician, almost for sure, you're going to be put
    > on a low-fat, high-carbohydrate diet.
    >
    > [Q:] What's your view of that?
    >
    > [Willett:] The problem is that that's really the wrong diet for an
    > overweight person. Because the person is overweight, in general they're
    > going to have quite a bit more insulin resistance and much less well able to
    > tolerate low-fat, high-carbohydrate diet."
    >
    > http://www.pbs.org/wgbh/pages/frontline/shows/diet/interviews/willett.html
    >
    > --
    > Juhana


    Willett makes sense. A higher carb, and therefore lower fat diet caused
    the obesity and the insulin resistance to begin with. To continue, or
    to make the higher carb diet even higher in carbs while restricting
    fats will only make the obesity and the insulin resistance worse.

    TC
     
  3. >>Don't get me wrong. I appreciate what you are saying. i think i understand
    just fine. But I'm betting that the "heterogeneity" of the diets
    followed by
    the participants was pretty minimal with respect to % CHO.<<

    Actually, we know ... precisely... the degree of heterogeneity.

    For the intervention group, it was 44.5% carbs at baseline, with a
    standard deviation (precise definition of heterogeneity) of 6.2. For
    the control group, it was 44.5% at baseline, also with a standard
    deviation of 6.2. (The numbers are not surprisingly identical, given
    the huge size of the study...nearly 50,000 subjects). After 7 years,
    the percent carbs in the intervention group was 52.7, with a standard
    deviation of 9.8. For the control group, it was 44.7, with a standard
    deviation of 8.5.

    What you'll see if you graph these out is a pretty standard looking
    normal distribution (i.e. not unusually narrow, which is what you'd see
    were there only limited heterogeneity. Basically, the standard
    deviation was 15-20% of the mean, which does indicate a substantial
    degree of heterogeneity. For the intervention group, 95% of the
    population would be between 33% carbs and 72% carbs. For the control
    group, 95% of the population would be between 27% carbs and 62% carbs.
    This is a pretty robust degree of heterogeneity, in my opinion.
    Obviously, very few would have been on an Atkins level of carb
    restriction, but that's not important in the context of what's
    important about the study, as you appreciate.

    - Larry W
     
  4. 11. Juhana Harju
    Jan 4, 12:36 pm show options

    Newsgroups: sci.med.nutrition
    From: "Juhana Harju" <[email protected]> - Find messages by
    this author
    Date: Wed, 4 Jan 2006 22:36:50 +0200
    Local: Wed, Jan 4 2006 12:36 pm
    Subject: Re: The definitive study on dietary fat and weight
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    [email protected] wrote:


    : Comments: The "low fat" diet was 27% calories as fat. Hardly low
    fat.
    : Carbohydrate quality wasn't controlled. The diets were isocaloric
    (ie.
    : controlled and forced feeding) and not ad libitum. All successful
    : diabetes prevention studies have been based on fat restriction and
    not
    : carbohydrate restriction. Postprandial blood sugars were
    : significantly lower in the prospective, randomized study previously
    : quoted on insulin resistant women when they ate 49% carbohydrates
    : than when they ate 11% carbohydrates. Postprandial triglycerides
    : (probably more important than fasting, though seldom measured) are
    : higher on higher fat diets.
    :
    : - -
    : - Larry W

    It would be interesting to hear your comment on what Willett says in
    one
    interview by Frontline TV:


    "[Q:] If you're American and overweight, won't you be put on a low-fat
    diet?


    [Willett:] If you're overweight and living in the United States, and
    you go
    to a hospital and see a dietician, almost for sure, you're going to be
    put
    on a low-fat, high-carbohydrate diet.


    [Q:] What's your view of that?
    >>[Willett:] The problem is that that's really the wrong diet for an

    overweight person. Because the person is overweight, in general they're

    going to have quite a bit more insulin resistance and much less well
    able to
    tolerate low-fat, high-carbohydrate diet." <<

    The ugly fact which ruins Willett's beautiful theory is that there is a
    lot of direct evidence to contradict him. High carbs promote insulin
    resistance when (1) they are administered in an artificial, forced
    feeding, isocaloric study design, (2) when they are high glycemic
    carbs, and (3) when they are administered in the absence of an exercise
    program.

    High carb ameliorate insulin resistance when (1) they are administered
    in a real world, ad libitum situation, (2) when they are low glycemic
    carbs, and (3) when they are administered inthe context of a
    non-pathologic (i.e. active, non-couch potato) lifestyle.

    The human body evolved to be health in the context of vigorous, daily
    exercise. It is pathologically abnormal, in an evolutionary context,
    to live the life of a couch potato. What may be (partially) true for a
    couch potato doesn't hold for a person with a non-pathologic lifestyle.

    And there are direct data to contradict Willett; which I've cited and
    discussed in detail on other recent threads.

    - Larry W
     
  5. >>I hit my La Pavoni and pull a couple of shots of espresso. I do add some
    steamed skim milk, though. <<

    I've had an Italian espresso machine on my kitchen counter at home for
    15 years, but only use it on special occasions (like either in the
    context of a really great lunch or when I'm going to be going on a long
    drive and want the caffeine hit without the need to stop and go to the
    bathroom shortly down the road). There are lipemic oils in coffee
    which are a problem for boiled, European style coffee, but which are
    nicely removed by the ubiquitous American coffee filters. I buy
    Starbucks French Roast at Costco and grind it fresh every morning and
    fill a pretty large thermous, which I pre-condition by filling it with
    boiling water).

    - Larry W
     
  6. What a marvelously interesting study. Thanks!

    - Larry W

    >>Scandinavian-style boiled coffee and

    Turkish-style coffee contained the highest amounts, equivalent to 7.2
    and
    5.3 mg cafestol per cup and 7.2 and 5.4 mg kahweol per cup,
    respectively. In
    contrast, instant and drip-filtered coffee brews contained negligible
    amounts of these diterpenes, and espresso coffee contained intermediate

    amounts, about 1 mg cafestol and 1 mg kahweol per cup. These findings
    provide an explanation for the hypercholesterolaemic effect previously
    observed for boiled coffee and Turkish-style coffee, and the lack of
    effect
    of instant or drip-filtered coffee brews. This methodology will be of
    value
    in more correctly assessing the human exposure to these diterpenes
    through
    the consumption of coffee, and hence the potential physiological
    effects of
    different brews." <<
     
  7. Juhana Harju

    Juhana Harju Guest

    [email protected] wrote:
    : What a marvelously interesting study. Thanks!
    :
    : - Larry W

    You can now have your nice cup of espresso without any feeling of guilt. ;-)

    --
    Juhana

    :
    ::: Scandinavian-style boiled coffee and
    : Turkish-style coffee contained the highest amounts, equivalent to 7.2
    : and
    : 5.3 mg cafestol per cup and 7.2 and 5.4 mg kahweol per cup,
    : respectively. In
    : contrast, instant and drip-filtered coffee brews contained negligible
    : amounts of these diterpenes, and espresso coffee contained
    : intermediate
    :
    : amounts, about 1 mg cafestol and 1 mg kahweol per cup. These findings
    : provide an explanation for the hypercholesterolaemic effect previously
    : observed for boiled coffee and Turkish-style coffee, and the lack of
    : effect
    : of instant or drip-filtered coffee brews. This methodology will be of
    : value
    : in more correctly assessing the human exposure to these diterpenes
    : through
    : the consumption of coffee, and hence the potential physiological
    : effects of
    : different brews." <<
     
  8. >>What is your concept of a "good" carb? Does a decent (all whole grain, dense
    and tasty) loaf of whole-wheat bread count?

    >>Are you mostly referring to low glycemic load?


    Yes. But, beyond glycemic load, some carb are still better than
    others.

    For example, al dente-cooked standard "white" pasta is low glycemic.
    But it's low in fiber and not as rich in micronutrients as whole grain
    pasta. But I eat almost exclusively white pasta (cooked al dente).
    Why? Because I tried the (Pritikin "mandated") whole grain pastas and
    I don't like them as much with the sort of sauces we prepare to go over
    them. So al dente white pasta is what I'd call a neutral carb. Not
    "toxic," certainly, but not as "good," as, for example whole grain
    pasta and certainly not as "good" as wheatberry bread or broccoli, etc.

    - Larry W
     
  9. Jim Chinnis

    Jim Chinnis Guest

    "Juhana Harju" <[email protected]> wrote in part:

    >Espresso does not seem to be a problem. These studies were a surprise to me
    >when I saw them some time ago:


    Juhana, the studies make no difference at all to me. To take my espresso
    away, you'd have to pry my cold, dead fingers from my La Pavoni. ;-)
    --
    Jim Chinnis Warrenton, Virginia, USA [email protected]
     
  10. Enrico C

    Enrico C Guest

    On 4 Jan 2006 00:15:16 -0800, [email protected] (Larry Weisenthal)
    wrote in <news:[email protected]>
    on sci.med.nutrition :

    > The largest, best, and most definitive study on the relationship
    > between dietary fat intake and weight has just been published in the
    > most recent edition of JAMA.
    >
    > Howard, B.V., et al. Low-fat dietary pattern and weight change over 7
    > years. The women's health initiative dietary modification trial. JAMA
    > 295:39-49, 2006 (January 4, 2006).
    >
    > There is a lot of stuff in it of secondary importance which I'll let
    > others talk about.
    >
    > But there is one particular finding of blockbuster importance. It is
    > absolutely and completely clear-cut and definitive. This was a study
    > in which subjects were randomized between a low fat/high carb diet and
    > no dietary intervention. Subjects were post-menopausal, obese women.
    > 19,000 were assigned to the low fat diet. 29,000 were assigned to usual
    > diet.


    Nevertheless, there were "low fat dieters" who even ate more fat and
    "non dieters" who, for some reasons, actually ate less fat, just as
    some "dieters"...

    > The low fat diet didn't come close to achieving its goals (20% calories
    > as fat). There was no exercise. No caloric restriction. But none of
    > that is important. What is of supreme importance are the data shown in
    > Fig 5, which I photographed and have temporarily posted on one of my
    > websites:
    >
    > http://www.weisenthal.org/swimming/jama_295_39-49_2006_fig_5.jpg
    >
    > Note that this figure shows results for nearly 50,000 women, followed
    > prospectively for 7 years.
    >
    > The figure shows the mean weight change in kilograms graphed on the
    > ordinate and quintiles of change from baseline in percent dietary fat.
    > Low lowest quintile represented those subjects (nearly 10,000) who
    > reduced their percent of calories fat intake by 11% or more.


    Mostly low fat dieters, I suppose, both in the intervention and
    control groups, right?

    > The
    > highest quintile represented subjects who increased their percent
    > calories as fat intake by 3.2% or more. The three other quintiles were
    > between these extremes. Each quintile represented data from nearly
    > 10,000 subjects followed 7 years.


    Seven years is a long time. When were the variations in dietary fat
    and weight measured?

    > Nole the perfectly linear relation between percent changes in percent
    > calories as fat and weight change, REGARDLESS of which group the
    > subjects were in. Those subjects who reduced fat intake


    Id est the dieters who actually dieted, in the "low fat diet"
    intervention group...

    Even in the control group, though, fat reduction might be due to some
    sort of personal dieting... We are talking of obese women and low fat
    dieting is quite common, isn't it?

    > lost weight
    > and kept it off.



    About 1 kg average weight loss (in the control group) after 7 years is
    not exactly a huge success for obese women, is it? All in all, they
    were still obese.



    > Those subjects who did not reduce fat intake


    Id est the non-dieters, for the main part, right?

    > did not lose weight.


    > Those subjects who increased fat intake (though not,
    > obviously, to the ketotic range) gained weight.


    Only 0.5 kg average weight gain after 7 years binging on fat?
    Not bad, for non-dieters with no exercise! ;)
    (I suppose they were non-dieters as low-fat dieters who actually
    dieted... reduced their dietary fat as a result, of course, thus
    should not be found in that quintile).


    > These trend line
    > relationships were highly significant (P2<0.001).


    > These data are perfectly consistent with the data from the U Pittsburgh
    > registry of people who successfully lost 15 kg and kept it off at least
    > 5 years. These subjects, on average, ate a diet comprising
    > approximately 24% fat


    Would you call 24% fat a "fat restricted diet"? I'd regard that as a
    quite balanced diet instead, neither high nor low in fat.

    > and close to 60% carbohydrate, if memory serves.
    >
    > These data obviously do not imply that the best diet for everyone is a
    > fat restricted diet. These data are, however, definitive in a
    > population sense.
    >
    > There can be no more serious argument. Body weight is unequivocally
    > related, in a highly significant fashion, to dietary fat intake, with
    > higher levels of dietary fat intake associated with weight gain and
    > lower levels of dietary fat intake associated with weight loss.


    I would like to know if those who reduced dietary fat and lost weight
    ate less calories as well. I strongly suspect that that is the case,
    because of two reasons:
    1) low-fat diet was the suggested weight control diet and is a common
    pattern for personal diets as well,
    2) it's easier to change quantities in dietary fat than in carbs or
    protein. No one eats, say, just fat and no carbs or protein. On the
    other hand, it's possible to eat protein and carbs and (almost) zero
    fat...
    In other words, fat reduction was a success when it also was caloric
    reduction?

    >
    > One might argue that these data only apply to obese post-menopausal
    > women, and I'm sure that the cult promoting carbohydrates as the true
    > cause of obesity will do so.


    I rather promote calories, lack of exercise and
    non-satiating/palatable foods as a possible cause of obesity.

    > But I agree with the conclusions of the authors:
    >
    > "There is no reason to assume that these findings cannot be
    > extrapolated to younger individuals and both sexes...because trends
    > showed that weight loss correlated with fat reduction, it is likely
    > these data can be extrapolated to persons who achieve lower fat and
    > higher carbohydrate intake."


    >
    > A true stake to the heart of the carbohydrate/obesity urban legend.
    >
    > - Larry W


    I agree with Jim Chinnis's remarks...
    In other words, it seems that the graph applies within the context of
    a high-carbohydrate diet, but doesn't tell much about low carbers.
     
  11. Jim Prescott

    Jim Prescott Guest

    In article <[email protected]>,
    [email protected] (Larry Weisenthal) <[email protected]> wrote:
    >For the intervention group, 95% of the
    >population would be between 33% carbs and 72% carbs. For the control
    >group, 95% of the population would be between 27% carbs and 62% carbs.
    >This is a pretty robust degree of heterogeneity, in my opinion.


    This really seems to make Jim Chinnis' point more than yours. <5% of
    the data in your graph applies to low-carb diets. That doesn't make
    the study uninteresting, but it does make your claim that the study
    represents a "stake to the heart" for low-carb rather spurious.

    That same graph but with only the few % of participants that are below
    20% carbs would show something about the role of fat in low-carb
    diets. A big premise of many of the low-carb diets is that this chart
    wouldn't look like the one you posted.
    --
    Jim Prescott - Computing and Networking Group [email protected]
    School of Engineering and Applied Sciences, University of Rochester, NY
     
  12. >>You can now have your nice cup of espresso without any feeling of guilt. ;-) <<

    The most "toxic" thing about espresso, based on your fine studies,
    would appear to be teeth staining.
     
  13. Susan

    Susan Guest

    x-no-archive: yes

    Jim Chinnis wrote:
    > "Juhana Harju" <[email protected]> wrote in part:
    >
    >
    >>Espresso does not seem to be a problem. These studies were a surprise to me
    >>when I saw them some time ago:

    >
    >
    > Juhana, the studies make no difference at all to me. To take my espresso
    > away, you'd have to pry my cold, dead fingers from my La Pavoni. ;-)


    I'll give up French press, and even the vaccuum pot, but not my strong
    filtered brew. I don't want to live a life without coffee.

    Susan
     
  14. dorsy1943

    dorsy1943 Guest

    I would like to know if a twenty per cent fat diet is twenty percent
    added fat from animal foods and oils other than vegetables or is it the
    ten per cent fat in the diet that comes with the spinach and grains
    etc. plus added fat. There are days when I think I am eating ten per
    cent fat because that is the number of fat calories I am adding in the
    form of olive oil. But Ornish says his diet is ten per cent fat but he
    only includes the fat already in the plant foods--like the 14 per cent
    fat in 100 grams of spinach.
     
  15. Susan

    Susan Guest

    x-no-archive: yes

    dorsy1943 wrote:
    > I would like to know if a twenty per cent fat diet is twenty percent
    > added fat from animal foods and oils other than vegetables or is it the
    > ten per cent fat in the diet that comes with the spinach and grains
    > etc. plus added fat.


    It refers to what percentage of daily caloric intake comes from fat.
    You can use fitday.com for free to see what your breakdown is; it uses a
    nutritional database for all nutrients.

    There are days when I think I am eating ten per
    > cent fat because that is the number of fat calories I am adding in the
    > form of olive oil. But Ornish says his diet is ten per cent fat but he
    > only includes the fat already in the plant foods--like the 14 per cent
    > fat in 100 grams of spinach.
    >


    Fat counts, no matter the source.

    Susan
     
  16. >From Enrico:

    >>Nevertheless, there were "low fat dieters" who even ate more fat and

    "non dieters" who, for some reasons, actually ate less fat, just as
    some "dieters"... <<

    Yes, this was a very real world study. 50,000 women followed over 7
    years. Unless you put people in jail, you can't control what they'll
    eat. I wouldn't be at all surprised were there so called "low fat"
    dieters who tried the Atkins Diet at some time or other.

    >>Mostly low fat dieters, I suppose, both in the intervention and

    control groups, right? <<

    Well, I'm sure that there were off an on dieters on many different
    types of diets in both groups over the seven years of the study. At
    the study's conclusion, though, the so-called "low fat" group was
    eating 30% calories as fat (down from 38.8% pre-study) and the control
    group was eating 38.1% calories as fat (down from 38.8% pre-study), so
    it appears that few in either group were following what I'd call a low
    fat diet (and certainly nowhere near the 20% target for the low fat
    group). But, again, this is real world. You can lead a turkey to water
    but you can't make him gobble.

    >>Seven years is a long time. When were the variations in dietary fat

    and weight measured? <<

    Women in both groups were contacted by telephone every 6 months for 7
    years and had annual physical exams, where height, weight, waist, and
    hip circumference were measured. Physical activity and dietary intake
    were regularly monitored for all subjects during the 7 years of the
    study. (from the "Methods").

    Quoting me:

    > Note the perfectly linear relation between percent changes in percent
    > calories as fat and weight change, REGARDLESS of which group the
    > subjects were in. Those subjects who reduced fat intake


    Enrico says:

    >>Id est the dieters who actually dieted, in the "low fat diet"

    intervention group...
    >>Even in the control group, though, fat reduction might be due to some

    sort of personal dieting... We are talking of obese women and low fat
    dieting is quite common, isn't it? <<

    All types of dieting is common in obese women.

    Enrico:

    >>About 1 kg average weight loss (in the control group) after 7 years is

    not exactly a huge success for obese women, is it? All in all, they
    were still obese. <<

    It was NOT a weight loss intervention study. That was never the
    purpose of the study. What was important about the study was not the
    "success" (or lack thereof) of the intervention, but rather the quality
    of the data collected. Compliance in the intervention group wasn't all
    that great and there was no exercise program (without which all long
    term weight loss programs are constrained to fail in the vast majority
    of participants). So some "control" subjects cut their fat intake on
    their own, and some intervention subjects actually increased their fat
    intake from baseline. What's important, though, is the striking,
    perfectly linear inverse relationship between fat intake and weight
    change.

    >>Only 0.5 kg average weight gain after 7 years binging on fat?

    Not bad, for non-dieters with no exercise! ;)
    (I suppose they were non-dieters as low-fat dieters who actually
    dieted... reduced their dietary fat as a result, of course, thus
    should not be found in that quintile). <<

    This isn't "binging" on fat. The average intake of all study
    participants at the start of the study was 38.8%. That's significantly
    more than is the case for the average person in the US at the time of
    the study. All the women were obese at the start (average BMI 30). On
    average, those who didn't change their baseline fat intake didn't
    change their weight. Those that increased it gained weight. Those
    that decreased it lost weight. The changes in weight were directly but
    inversely proportional to changes in fat intake.

    The absolute magnitude of changes in a very heterogeneous population
    underestimate the importance of the differences in the changes being
    measured. If all forms of cancer were cured today, then average life
    expectancy would be improved by only about 2 years.

    >>Would you call 24% fat a "fat restricted diet"? I'd regard that as a

    quite balanced diet instead, neither high nor low in fat. <<

    Well, the average percent fat intake for Americans is on the order of
    34%. So 24% represents a 30% reduction, compared to average. But we
    can infer (from the study in question, for example) that obese people
    may have even higher fat intakes (the 50,000 obese women in this study
    ate an average of 38.8% fat, pre-intervention; so compare 24% with
    38.8% and that's quite a reduction. Also, please note that many
    so-called "low fat" diet studies have used 30% calories as fat as the
    definition of a so-called "low fat" diet!

    >>I would like to know if those who reduced dietary fat and lost weight

    ate less calories as well. I strongly suspect that that is the case,
    because of two reasons:
    1) low-fat diet was the suggested weight control diet and is a common
    pattern for personal diets as well,
    2) it's easier to change quantities in dietary fat than in carbs or
    protein. No one eats, say, just fat and no carbs or protein. On the
    other hand, it's possible to eat protein and carbs and (almost) zero
    fat... <<

    Well, of course they ate less calories. Unless you increase exercise
    (and there is no evidence that the "low fat" group increased exercise)
    the only way you can lose weight is to reduce calories. This confirms
    many studies which show, in an ad libitum situation, that reducing fat
    content of ingested food leads to lower ingestion of calories.

    At the beginning of the study, average caloric intake was 1788 calories
    for intervention group and 1789 for control group. After 7 years,
    average caloric intake was 1446 for the intervention group and 1564 for
    the control group.

    >>I rather promote calories, lack of exercise and

    non-satiating/palatable foods as a possible cause of obesity. <<

    I mostly agree. I'd put lack of exercise number one and slight
    increases in total caloric consumption as number two.

    >>I agree with Jim Chinnis's remarks...

    In other words, it seems that the graph applies within the context of
    a high-carbohydrate diet, but doesn't tell much about low carbers. <<

    When you guys refer to "low carbers," I presume that you mean extreme
    (e.g. Atkins style) low carbers? This was in no way a specific study
    of the Atkins diet. The results pertain to Americans eating pretty
    much standard American diets (I gave the 95% confidence intervals for
    intake of carbs and fats in other message).

    - Larry W
     
  17. Enrico C

    Enrico C Guest

    On 4 Jan 2006 14:08:19 -0800, [email protected] (Larry Weisenthal)
    wrote in <news:[email protected]>
    on sci.med.nutrition :

    > Yes. But, beyond glycemic load, some carb are still better than
    > others.
    >
    > For example, al dente-cooked standard "white" pasta is low glycemic.


    Yep! :)

    > But it's low in fiber and not as rich in micronutrients as whole grain
    > pasta.


    True.

    > But I eat almost exclusively white pasta (cooked al dente).


    The "cooked al dente" part is quite important, not just for its taste
    but for the glycemic value, of course...

    > Why? Because I tried the (Pritikin "mandated") whole grain pastas and
    > I don't like them


    You are not the only one. Well, I like both white and whole grain
    pastas, but there are many people who think that only white pasta
    tastes as real pasta... :)


    > as much with the sort of sauces we prepare to go over
    > them. So al dente white pasta is what I'd call a neutral carb.


    Agreed.

    > Not
    > "toxic," certainly,


    It all depends on doses. I think 50 to 80 grams of pasta in an average
    meal is fine. I am not dieting though.

    > but not as "good," as, for example whole grain


    But you can have plenty of fiber (maybe of a more useful kind?) from
    other sources than wheat bran...

    > pasta and certainly not as "good" as wheatberry bread or broccoli, etc.


    I like pasta *and* broccoli (or other vegetables) :)

    --
    Enrico C

    * cut the ending "cut-togli.invalid" string when replying by email *
     
  18. Just Cocky

    Just Cocky Guest

    On 4 Jan 2006 13:05:49 -0800, "[email protected] (Larry Weisenthal)"
    <[email protected]> wrote:
    >
    >>>Don't get me wrong. I appreciate what you are saying. i think i understand

    >just fine. But I'm betting that the "heterogeneity" of the diets
    >followed by
    >the participants was pretty minimal with respect to % CHO.<<
    >
    >Actually, we know ... precisely... the degree of heterogeneity.
    >
    >For the intervention group, it was 44.5% carbs at baseline, with a
    >standard deviation (precise definition of heterogeneity) of 6.2. For
    >the control group, it was 44.5% at baseline, also with a standard
    >deviation of 6.2. (The numbers are not surprisingly identical, given
    >the huge size of the study...nearly 50,000 subjects). After 7 years,
    >the percent carbs in the intervention group was 52.7, with a standard
    >deviation of 9.8. For the control group, it was 44.7, with a standard
    >deviation of 8.5.
    >


    Given the different standard deviations, have you tested for a null
    (no difference) hypothesis? If yes, at what level of significance?
     
  19. Just Cocky

    Just Cocky Guest

    On Wed, 4 Jan 2006 23:36:51 +0100, Enrico C
    <[email protected]> wrote:
    >
    >> The low fat diet didn't come close to achieving its goals (20% calories
    >> as fat). There was no exercise. No caloric restriction. But none of
    >> that is important. What is of supreme importance are the data shown in
    >> Fig 5, which I photographed and have temporarily posted on one of my
    >> websites:
    >>
    >> http://www.weisenthal.org/swimming/jama_295_39-49_2006_fig_5.jpg
    >>
    >> Note that this figure shows results for nearly 50,000 women, followed
    >> prospectively for 7 years.
    >>
    >> The figure shows the mean weight change in kilograms graphed on the
    >> ordinate and quintiles of change from baseline in percent dietary fat.
    >> Low lowest quintile represented those subjects (nearly 10,000) who
    >> reduced their percent of calories fat intake by 11% or more.

    >
    >Mostly low fat dieters, I suppose, both in the intervention and
    >control groups, right?
    >


    Actually, do we know for sure that those who ate more fat, ate less
    carbs? Or did they eat more carbs too? Couldn't it be that those who
    ate more fat ate more of everything?

    >
    >About 1 kg average weight loss (in the control group) after 7 years is
    >not exactly a huge success for obese women, is it? All in all, they
    >were still obese.
    >


    Hmm, from a statistical point of view, 1kg might not even be
    significant. What were the standard deviations?
     
  20. Jim Chinnis

    Jim Chinnis Guest

    "runns[email protected] (Larry Weisenthal)" <[email protected]> wrote in part:

    >>>Don't get me wrong. I appreciate what you are saying. i think i understand

    >just fine. But I'm betting that the "heterogeneity" of the diets
    >followed by
    >the participants was pretty minimal with respect to % CHO.<<
    >
    >Actually, we know ... precisely... the degree of heterogeneity.
    >
    >For the intervention group, it was 44.5% carbs at baseline, with a
    >standard deviation (precise definition of heterogeneity) of 6.2. For
    >the control group, it was 44.5% at baseline, also with a standard
    >deviation of 6.2. (The numbers are not surprisingly identical, given
    >the huge size of the study...nearly 50,000 subjects). After 7 years,
    >the percent carbs in the intervention group was 52.7, with a standard
    >deviation of 9.8. For the control group, it was 44.7, with a standard
    >deviation of 8.5.
    >
    >What you'll see if you graph these out is a pretty standard looking
    >normal distribution (i.e. not unusually narrow, which is what you'd see
    >were there only limited heterogeneity. Basically, the standard
    >deviation was 15-20% of the mean, which does indicate a substantial
    >degree of heterogeneity. For the intervention group, 95% of the
    >population would be between 33% carbs and 72% carbs. For the control
    >group, 95% of the population would be between 27% carbs and 62% carbs.
    >This is a pretty robust degree of heterogeneity, in my opinion.
    >Obviously, very few would have been on an Atkins level of carb
    >restriction, but that's not important in the context of what's
    >important about the study, as you appreciate.


    I see that the screening criteria eliminated everyone who had a % fat intake
    above 32%. That would exclude every low-carb dieter. That is at baseline, of
    course, but we have only the SEs to estimate distributions at later points
    in time.

    While the study seems very well done, and the data certainly speak against
    the argument that reducing fat in most diets increases weight, what I see in
    the paper fails to address the low-carb diet range. Yes, there is obvious
    heterogeneity, but the dice were biased to exclude those who liked/chose
    high-fat diets.

    I would be cautious about using the means and SEs to estimate anything about
    the tails of the % fat distributions. And low-carb diets fall in the upper
    tail.

    You definitely did home in on the most interesting aspect of the study--the
    first panel of Figure 5. It's just too bad that those % fat changes don't
    bring any substantial part of the (truncated!) baseline distribution into
    the low-carb zone.
    --
    Jim Chinnis Warrenton, Virginia, USA [email protected]
     
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