A dear
reader – and I mean that sincerely because I wouldn’t write this blog except
for my readers – was disappointed (upset, actually) that I said, “…if you are
insulin resistant, as almost all fat people are…” Okay, “fat people” is an
inflammatory phrase, and I have never
used it before, but that is not what
upset Valerie. It was an assumption, and a slight
exaggeration that I made, that did the trick. She concluded: “I wish your
‘nutrition debate’ weren’t so one-sided.”
Valerie’s
frustration (and upset) is a result of my writing about two overlapping and
related but different phenomena: the co-incident epidemics of diabetes and
obesity that have come together in the last 35 years. It
all began with the publication of the Dietary Guidelines for Americans in
1980, the U.S. government’s attempt to tell us as a population what to eat.
That followed the 1977 Dietary Goals for Americans produced by a Select
Committee of Congress: the McGovern Commission.
This
combination of type 2 diabetes and obesity is so prevalent today that the word
“diabesity” has been coined. However, as
Valerie points out, not all “fat people” have Insulin Resistance (IR), a
requisite condition for progression from a normal glucose metabolism to
Impaired Glucose Tolerance (IGT), Impaired Fasting Glucose (IGT), and then to a
frank diagnosis of Type 2 Diabetes Mellitus (T2DM). That is the Natural
History of Type 2 Diabetes. Apparently Valerie is not Insulin Resistant or
therefore by definition a type 2 diabetic (FBG at diagnosis ≥126mg/dL) or
pre-diabetic (FBG from 100 to 125mg/dL).
So, I give
Valerie her point that, “…there are plenty of slim people with insulin
resistance and plenty of fat people without insulin resistance…” I will resist
getting into a “pissing contest” over percentages. I will concede that
apparently Valerie is one of them. But I will
contest the assertion Valerie makes that “fat people without insulin
resistance” did not benefit from the “A to Z diet trial.” She states erroneously that “low-carb diets don’t
help [them], if you remember the A to Z diet trial.”
The A to Z diet trial, not to be
confused with a statin trial by a very similar name, was a “Twelve-month
randomized trial conducted in the United States from February 2003 to October
2005 among 311 free-living, overweight/obese (body mass index, 27-40) nondiabetic [emphasis mine],
premenopausal women.” Note: this trial EXCLUDED (type 2) diabetics, which by
definition means that the participants did not
have IR. It was a “Comparison of the Atkins, Zone, Ornish, and LEARN diets for
change in weight and related risk factors…,”published in JAMA in July 2007. The
following are excerpts from the ABSTRACT:
“MAIN
OUTCOME MEASURES:
Weight loss at 12 months was the primary outcome. Secondary outcomes
included lipid profile (low-density lipoprotein, high-density lipoprotein, and
non-high-density lipoprotein cholesterol, and triglyceride levels), percentage
of body fat, waist-hip ratio, fasting insulin and glucose levels, and blood
pressure.”
“RESULTS:
Weight loss was greater for women in the Atkins diet group compared with the
other diet groups at 12 months, and mean 12-month weight loss was significantly
different between the Atkins and Zone diets. Weight loss was not statistically
different among the Zone, LEARN, and Ornish groups. At 12 months, secondary
outcomes for the Atkins group were comparable with or more favorable than the
other diet groups.”
“CONCLUSIONS:
In this study, premenopausal overweight and obese women assigned to follow the
Atkins diet, which had the lowest carbohydrate intake, lost more weight at 12
months than women assigned to follow the Zone diet, and had experienced
comparable or more favorable metabolic effects than those assigned to the Zone,
Ornish, or LEARN diets…”
So, just to
be perfectly clear, non-diabetic, premenopausal overweight and obese women who ate the diet
with the lowest carbohydrate intake lost the most weight and had the best
improvement in related risk factors (including “lipid profile
(low-density lipoprotein, high-density lipoprotein, and non-high-density
lipoprotein cholesterol, and triglyceride levels), percentage of body fat,
waist-hip ratio, fasting insulin and glucose levels, and blood pressure.”)
In other words, the low-carb diet
DID help “fat people without insulin resistance,” and by a large margin. After
12 months, the Atkins cohort actually lost 3 times as much weight at the Zone
cohort and twice as much as the average Ornish and LEARN dieter and had
“comparable or more favorable metabolic effects” than those on the Zone,
Ornish, or LEARN diets.
I’m sorry to have to come down so
hard on this point, but it must be made clear to all my dear readers
that low-carb diets do work (for the vast majority of people, if I have to hedge). If you haven’t given it
an honest try, you really should.
This is not a "pissing contest" about percentages. I was questioning your assertion that almost all fat people are insulin resistant. I don't see what data makes you so sure about it.
ReplyDeleteAs for the A to Z trial, some participants did have insulin resistance (but not diabetes). My previous comment was about the subgroup analysis they did, not the overall averages [sorry, I should have made that clearer]. Among the participants with IR, Atkins was the best. Among the participants without IR, Ornish was the best if I remember correctly.
I think this is where the author talks about it:
https://www.youtube.com/watch?v=eREuZEdMAVo
Valerie, thanks for commenting again. I just watched the 1:16 YouTube presentation by Christopher Gardner. I was pretty impressed that a 25 year vegetarian could be and was as objective as he was. He admitted it was a "bitter pill" to have to report the superiority Atkins to the other diets,
ReplyDeleteWith respect to the "bone" you have picked re Insulin Resistance, I paid particular attention. At about minute 42 he shows a slide from another study that compares IS and IR but this was not from the A to Z study. Then, at about minute 44, he shows a slide from the A to Z study that says (and I'm paraphrasing): For insulin resistance, the low fat diet is 'ineffective' compared to the low carb. Then at minute 45, in answer to a question that was unintelligible, he says, the more overweitht you are, the fore insulin resistant you are. Later on, in answer to another question, he says, if you have metabolic syndrome, you probably have insulin resistance. Of course, he is addressing a 'naive' audience, and I think you and I could have a more nuanced conversation (debate?) on the subject, but I could not find where he said anything which is dissonant with my admittedly somewhat exaggerated and insensitive statement that "almost all fat people are insulin resistant."
PS: Have you ever had a HOMA2 test. An endo I saw two years ago (1 time, he fired me) did one at my request. His nurse said he had never done one in 12 years and he had to look it up. He said it was mostly done for research but he agreed to do it. My beta cell function was 68.2% and my insulin sensitivity was 94.6%. I was quite surprised by both. I think you would find the column #86 and #87 interesting. I link them below.
http://www.thenutritiondebate.com/2013/02/the-nutrition-debate-86-beta-cell.html
http://www.thenutritiondebate.com/2013/02/the-nutrition-debate-87-optimal-blood.html