The Paleo Diet
by Loren Cordain
Review by Khurram Hashmi
Date: Sun, 13 Jan 2002 09:22:18 ESTAuthor: Khurram Hashmi
Subject: [CR] _The Paleo Diet_ by Loren Cordain
Date: Sun, 13 Jan 2002 09:22:18 EST From: Subject: [CR] _The Paleo Diet_ by
Loren Cordain
Just hitting the bookstores is The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat (published 2002 by John Wiley & Sons; ISBN: 0471413909) by noted paleo researcher, Loren Cordain. Although I'm not quite done reading this book, I though I'd post some of the paradigms that Cordain outlines. They are:
Eat a "high" protein diet
- Protein should come from lean meats and fish, which Cordain says are *the* ideal source. Pasture-fed, organically raised animals are ideal (see below for fish).
- Organ meats are ok (and even recommended) -- no mention of AA dangers
- Average (AL) person should consume 200-300g protein/day. This is, surprisingly, based on older (1997) research; latest evidence -- his own, as a matter of fact
-- suggests 142-262g/day. See: http://groups.yahoo.com/group/crsociety/message/9762.
Example: for the average AL female, at 2200kcals/day, _The Paleo Diet_ recommends 190g/day, all from lean, non-dairy animal sources.
- The thermic effect. Protein increases metabolism and causes one to burn more calories than fat or CHO. But, I'm not sure if a VERY high protein intake, as per Cordain's plan, is desirable (IF a lot of these protein calories are being absorbed). The thermic effect, therefore, is more beneficial to those concerned with weight loss than CR. I think the tricky part is finding that optimal balance between the benefits of a hi-protein diet and a "higher-than-normal" thermogenesis.
Watch out for acid-base imbalance:
Cordain stresses one eat LOTS of alkaline-rich foods (veggies and fruits)
- always good advice! This is due to the fact that the consumption of meats, fish and eggs produce a net acid load, which causes one to excrete calcium in their urine. The acid imbalance is exacerbated if one consumes grains and dairy, not to mention the chloride from salt (or salt-enriched foods). Veggies and fruits will balance the equation if and only if one maintains a low-salt, dairy/grains/legume-free diet. In Appendix A (p. 213), there is an excellent chart comparing acid-base values of common foods.
Eliminate salt use:
Most of the effects of a high-salt are not worth repeating. The one that I found especially interesting was the negative effect of salt on sleep [1].
Avoid grains, legumes:
These are absolute no-no's...and Cordain repeatedly warns the reader in consuming them. Other than their net-acid load and high (or higher) CHO/GI, their anti-nutritive qualities are also stressed, particularly pyridoxine glucosides, which can prevent vitamin B6 absorption, and phylates, which prevent Fe, Cu, Ca, Zn absorption.
Avoid dairy:
This no-no is also repeatedly mentioned in _TPD_. Here, however, Cordain's cautions are not as well-founded as those pertaining to grains and legumes.
To his credit, certain dairy products, such as hard cheeses, do have a high-acid load. But he fails to note that this is due to their high NaCl content (Cl in particular). Whole milk only has a net acid load of +0.7 (not too far from cucumbers, which have a net-acid (alkaline) load of -0.8). Cordain also makes no mention of whey protein, which has many things going for it and is better than lean meats/fish in several aspects. Surprisingly, and despite his very direct, self-assured prose, the author notes "To date, no dietary intervention studies have been conducted to see whether Paleo diets - free of grains, dairy products, and legumes - can reduce the symptoms of these diseases." (p. 91)
Fish:
There are many words of praise for fish. However, Cordain warns against heavy metals, PCBs, and pesticides/herbicides. His recommendations are:
- avoid freshwater fish
- choose fish from cleaner waters: Pacific Ocean or Alaska
- eat smaller, non-predatory species: flounder, sole, Pollock, catfish, halibut
and clams
- eat big, predatory, long-lived fish sparingly - swordfish, tuna, shark
- avoid farm-raised fish, which is grain-fed Canned fish is not recommended
because the high heat and canning process removes most of the nutrients and increases oxidized cholesterol.
Eggs:
They are fine, if used no more than 6x per week. Cordain recommends the omega-3 variety. However, he cautions that the way they are cooked is critical to the level of oxidized cholesterol that may be created. Poaching, hard-boiling or baking is best.
Macro ratios:
On page 11, Cordain recommends P:C:F = (19-35:22-40:28-47). On Page 41, Cordain states: "My research team and I have found that ideally, a little more than half - 55 percent - of your calories should come from lean meats, organ meats, fish, and seafood." Most of his recommendations lean towards the higher end of the protein range.
- Recipes from _TPD_:
They seem to be very well created with the exception of promoting the use of certain plant oils (olive, flax) to cook foods. When I
bake fish (which has now become rare as I usually boil it) I will use 5g of unsalted butter (the full-fat variety) to grease the pan. IMO, this reduces the intake of heat-damaged lipids.
Cordain's protein requirements (per meal) are higher than Sears' 35g/meal limit. How do the kidneys hold up with the added protein? MR somewhat put this concern to rest in some private messages we exchanged last summer.
I'll post one of the messages here:
-------------------------------------------------------------
> In a message dated 2001-09-15 5:14:25 PM Pacific Daylight Time,
> mikalra AT cadvision.com writes:
>
> > > I take
> > > it you, the, concur with Sears' claim that a MAX of 35g (total animal
> > >+
> > > vegetable) per meal every couple of hours is okay...as far as renal
> > > function goes?
> >
> > As I've documented painstakingly in the past, there does not appear to
> > be any credible evidence that ANY amount of protein is detrimental to
> > human kidneys.
>
> Yes you have! And you convinced me of that some time ago. My only concern
> was the amount of protein PER meal (not total).
Ah! Gotcha. Well, this is less certain, as I don't know anything
specific about the spacing of the protein in these trials; however, I
strongly expect that this can't make much difference, either. The
reason: the standard N American pattern is v. high-carb, nearly
no-protein breakfast, a reasonable lunch, & a ridiculously oversized
dinner protein serving. Thus, if the studies on TOTAL protein come up
w/no detrimental impact, then (methinks) the same studies are PROBABLY
telling us that large amounts f protein in a SINGLE MEAL can't be
terribly detrimental, either.
> BTW, what is YOUR total protein
> intake these days PER meal and per a 24hr period.
Well, per meal varies by the Caloric content of the meal, but the total
is still an av'g 125 g.
> If I recall from the post
> some time ago on your diet, it was 120g/day. This seems a bit LOW based
> on
> some of your current posts (namely "Paleo Protein").
There is, AFAIK, no evidence for health bennies for truly Paleo protein
intakes over SAD (which, by interesting coincidence, is the ballpark I'm
actually in!). As I've mentioned before, I don't take the Paleo diet as
a PRESCRIPTION, but as an EXPLANATION for why known problems w/specific
foods or dietary patterns. Hence, eg. it's clearly demonstrable that the
SAD's n6:n3 is detrimental. Why? Methinks, genetic discordance: our
eicosanoid-manufacturing machinery is built on the "assumption" of a low
n6:n3, & maladapts to something else. But in the absence of a known
"issue," I'll gladly eat non-Paleo foods like eggplant, or a
Paleolithically incorrect "low" protein intake.
> Due to the NPU data you
> recently discovered AND the latest paleo data, have you upped your
> intake,
> namely to compensate for your vegetarian diet? Or are you compensating
> with
> more available/usable lacto-ovo ingredients?
Nope! I ALWAYS believed that vegan protein sucked, & so didn't "depend"
on it. If anything, the npu data are MORE favorable to such sources than
I'd believed reasonable.
-Michael
-------------------------------------------------------------
Although Cordain does not recommend a specific upper limit (per meal), he does mention that w/o simultaneous CHO or fat intake, one can put
him/herself into "protein toxicity." Specifically, he notes: "The body has clear limits, determined by the liver's inability to handle excess dietary nitrogen (released when the body breaks down protein). For most people, this limit is about 35 percent of your normal daily caloric intake. If you exceed this limit for a prolonged period of time, your body will protest - with nausea, diarrhea, abrupt weight loss, and other symptoms of protein toxicity." (p.67).
- Summary:
Given Loren Cordain's credibility in the field of Paleolithic nutrition, I was expecting much more scientific and/or in-depth discussions. The book is devoid of charts, graphs and illustrations. This is disappointing. I think we need a follow up to Eaton's _The Paleolithic Prescription_. Compared to that classic text, _TBD_ is all-too-brief (248 pages), and not nearly as well written. Cordain simply asks you to take his word for his recommendations rather than explaining the logic behind some of his reasoning. Perhaps his audience is the layperson; OTOH, many layfolks don't even know the *meaning* of the word "Paleo." The author also fails to present challenging (and credible) opinions form other paleo-theorists such as Katherine Milton [2,3]. She argues that plant-based foods played a much more important role than that claimed by Cordain and his colleagues. As a matter of fact, Cordain, in the _TPD_ , uses Milton's research [4] to dispute her claims: he compares the evolution and relative size of our guts to those of chimps and other apes (p. 38). Given the relatively small size of our bellies, he concludes that we were largely meat eaters. The evidence, for the most part, seems to support Cordain. However, many of us CRONies have diets that are very high in plant matter. I am surprised at how much my belly can hold!
Finally, Cordain's reference scheme is shabby! It's even worse than Sears'. The Bibliography section is presented in alphabetical order only. It is not divided into chapters, much less the more-desirable reference-number system.
For the seasoned CRONie, there is not a lot of insightful info in this book. If you're interested, get it from your local library or pick it up used.
- Khurram Hashmi
[1] Miller MM. Low sodium chloride intake in the treatment of insomnia and tension states. JAMA 1945; 129:262-266. (Sorry, couldn't find the PubMed abstract).
[2] Reply to L Cordain et al. Am J Clin Nutr. 2000 Dec;72(6):1590-2. PMID: 11101498
[3] Milton, K. Reply to SC Cunnane. Am J Clin Nutr. 2000 Dec;72(6):1586-8. PMID: 11101494
[4] Milton, K. Primate diets and gut morphology: implications for hominid evolution. In: Harris M, Ross EB (eds.), Food and Evolution. Philadelphia: Temple University Press, 1987, pp. 93-108