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The Albatross -- Introduction
This huge, well-researched article was written in 2000 by MR. In it, MR concludes that a Zone diet (originally popularized in a series of books by Barry Sears) is the healthiest popular-diet program.
On Wed, 20 Sep 2000
Your wish is my command!!
Well, sort of ...
Folks, I started this off with much fire and bluster, and though it's been a good learning experience, it's also become a bit of an albatross. I started off thinking that I could whip up a decent Apologia Pro Zona in a couple of weeks, just from data I had kicking around the house and a few ideas in my head. Not so! One thing was always leading to another ... one more paper to review, one more fact to confirm, one more argument whose logic seemed to have a gap. Plus, I found I had a LOT less time on my hands than I'd expected, for many reasons, including what I believe to have been record-high posting volume this summer. I simply do not have the time to follow up on all the data, all the arguments, all the loose ends.
The below is incompletely referenced, somewhat jumbled in structure, and includes places where arguments just trail off midway thru. This was not intended, but it's going to have to do.
OTOH, I accepted from the beginning that much of what would follow is make-the-case argumentation. There's no need to point this out: I'm fully aware of it. But the cases are made with real, live science. Read such arguments w/an appropriate quantity of NaCl -- but also look at the extensive controlled trials favoring a Zone diet. These, alone, IMHO establish that a Zonish diet is in every way superior to a high-CHO [CHO is molecular acronym for carbohydrate, or Carbon-Hydrogen-Oxygen] one.
I'm posting this in 2 halves, for easy reading: this half is the text, the other is the references. If you open them up separately, you can then jump from one window to the other to check references, rather than constantly scrolling and losing your place.
How this all began:
On Mon, 5 Jun 2000
When I first read the above, I thought memory was playing tricks on me, but I went back to the archives of my very first month on the list (sniff!) looking for something else, and in the process confirmed my recollection. PH, you've been on this list for longer than I have; unless you put a kill file on my posts almost from day one of my list presence, you should have seen DOZENS of posts including experimental and clinical data providing scientific justification for the Zone, both as a whole and in its various aspects, from a health perspective!
Well, here we go for a massive, hopefully once-and-for-all, discourse. Don't take this as a personal attack, please! Whom the LORD loveth, He chasteneth.
Let's start at the very beginning.
The Zone is a calorie-restricted diet. CR is the only intervention which can be shown to consistently and repeatedly extend the mean and maximum LS of mammals. I take It I needn't belabor this point further.
The Zone is a nutritional program which is, as compared to Walford's recommendations:
A) similar in absolute protein for most folks (but really, it should be set much HIGHER -- see below),
B) with a controlled protein-to-carbohydrate ratio
C) achieved by cutting down on empty carbohydrates such as grains, potatoes, and sugar. It also recommends...
D) a much higher fat intake,
i. sufficient to maintain EFAs (essential fatty acids), but also
ii. high in monounsaturated fat (MUFA).
What justification is there for these recommendations -- again, leaving aside the proven facts that they result in more successful weight loss (a serious health issue for the North American population, if not for most CRONies), and better satisfaction, which is likely to lead to more comfort and better lifelong commitment to CR (again, itself a far from trivial issue)?
I take Sherm's [a former poster on the CR Society mailing list] word that "[Barry] Sears' theory is pretty much quackery. There seems to be no experimental or epidemiological justification."
There is plenty of both. Direct experiments on the full Zone program, including both CR and the proper macronutrient ratios, which address known disease risk factors as opposed to issues of diet adherence or weight loss (the inclusion of which would extend the set considerably) include:
BARRY SEARS, PAUL KAHL, GEORGE RAPIER. A Nutrition Intervention Program to Improve Glycemia, Lipid Profiles, and Hyperinsulinemia in Patients with Type 2 Diabetes. Diabetes 1998; 47(S1): A312.
The data can be accessed at Sears site, with a free login ID:
Title: Effects of Two Energy Restricted Diets on Fuel Utilization, Blood Chemistry, and Body Composition.
Researchers: M. Kern, V. Schuab, and D. Harris, from the Department of Kinesiology, San Francisco State University, SF, CA.
Source: Med Sci Sport Exer. 1998 May;30(5) Supplement; S1-S1339
This study reported the typical lipid changes we re used to seeing in Zoners; however, it was small and rather flawed, as Curt Adams pointed out at the time.
An independent study was also unwittingly performed by Markovik et al (1,2).
It will be objected that these are not the results of the Zone qua Zone, but of CR. Indubitably, this plays a major role in these results. But compare these results to Walford's (3, 4, 5) and a picture emerges which suggests the Zone's superiority.
Let me first state that I think I am exaggerating the performance of the Walford group by accepting their pre-closure data points as their baseline and their 6 mo data points (5) as the effect of CR alone. CR did not begin until closure, but very vigorous exercise began well before this, and their baseline was taken 2 mo before closure, so that the first data point is the result of short-term CR and medium-term increases in exercise. Otherwise, we must accept that just two weeks of CR produced some very dramatic changes in body composition and lipid levels indeed -- in fact, little improvement was seen on most measure's thereafter, and some got worse.
Second, it is important to use Markovik's normoglycemic subject data as a Zone comparison. Markovik used both diabetic and normal subjects, and his results clearly show that the Zone program worked much better on normals: NIDDM started off worse, and did not improve by as great an amount. In the section on protein, Below, I present what I believe to be pretty clearly the reason for this fact. Since Walford's biospherans were all normals, and Sears study was in NIDDM only, Markovik's normal subjects data is to be a fairer comparison to Walford's. Let me state up front that this results in more favorable results of the zone program than does using Sears NIDDM data. However -- fro reasons to be discussed in the P:C review below -- it is fully to be expected that healthy folks will respond better to the Zone than will NIDDM patients.
Also, Walford's group had 6 months to achieve their improvement, where M's group had but 4 weeks; OTOH, Walford's group seems to have achieved most of their changes almost immediately (with the caveat above).
On the other hand, Markovik's group was more severely restricted (1100 Cal vs. 1800) -- but note that we would expect some very different sorts of differences from an increased CR degree in otherwise similar diets than the ones observed (i.e. quantitative rather than qualitative). Indeed, I will suggest below that the disadvantages of a low-fat CR diet (noting that ANY CR diet is superior to ANY AL (ad lib) diet in extending longevity) ACCELERATE with lower caloric intake.
It will also be objected that Markovic did not do the full Zone program, because his macronutrient profile held across the day, rather than being constant at each meal. I will provide the justification for the importance of holding the P:C ratio AT EACH MEAL below. For now, (a) see Sears, and (b) remember that the overall daily profile still held, as compared to Walford's.
Finally, all of Markovic's day 28 data is on charts rather than tables or detailed text summaries, so I have to eyeball the results.
Total cholesterol fell by 17.9% (4.86 to 4 mmol/L) on the Zone (z). and by 35% on Walford's program (w). LDL fell 29% (2.47 to 1.75) in z, and 53% (calculated: 79.7 vs. 37.27 mg/dL) in w.
But while these measures improved more significantly in Walford's group, HDL simultaneously declined 37%, so that the TC:HDL (CVD risk ratio) was in fact not significantly changed (3.45 vs. 3.49) by the program. In contrast, Markovic says that Zoning subjects saw no significant changes in HDL (no data given in the paper as to the final figures, but they started at 1.32), improving their risk profile (3.68 vs. 3.03).
Similarly, TG (triglycerides) declined in Walford men by 21%, but they INCREASED in the Walford women by 53%! Averaging the data out, we get a mean decline of TG of 3.2% (108.5 to 105). By contrast, TG went down 21.6% (1.02 to 0.8 mmolL) in Zone.
Now: the TG:HDL ratio, whether or not it is an insulin surrogate (see below), is an extremely powerful predictor of MI ( the ratio of triglycerides to HDL was a strong predictor of myocardial infarction (RR in the highest compared with the lowest quartile=16.0; 95% CI=7.7 to 33.1; P for trend <.001) -- go ahead, read that again: RR=16!! ). Walford's ratio got 36.6% worse (1.75 vs. 2.76). Granted how extremely predictive this ratio is, it would seem that WALFORD'S PLAN MAY ACTUALLY HAVE CONSIDERABLY INCREASED RISK OF DEATH FROM MI (myocardial infarction). By contrast, Zoners saw their ratio decline by 21.3% (0.77 to .61) -- and again, the highly predictive nature of the ratio makes this a much more profound decline than it sounds.
And bringing the Biospherans caloric intake down to Markovic's levels is only likely to make this worse. I make this speculation on the basis of (40). This trial found that the problems associated with low-fat eating -- lowered HDL and elevated TG -- stay stable and get worse (respectively) as caloric intake decreases. what they actually report is that TG only start to go down on low-fat, high-CHO when energy is restricted below AL; this, however, contradicts all the evidence below, which shows increased TG under AL low-fat, high-CHO conditions. I conclude that it is more likely that Walford's group might have gotten WORSE STILL relative to Zone, from a blood lipid ratio perspective, had caloric intake been brought down to Zone levels, than that they would have caught up.
These results are paralleled in AL dieters, as will be seen in following sections. Let's take the Zone program point by point.
Next: Part One: More Fat