Dear Paleoids,
 I looked into this Okinawan diet thing a month ago when a friend asked
me about it after she saw an article in the Boston Globe. Here is part
of the letter I sent her about it:

"The article on Okinawans was very sketchy, but certainly interesting
and thought provoking. I may want to check out the book. One shouldn't
be too easily swayed by studies, and reports on studies in the media.
Okinawan life expectancy is 81.2, and in the U.S. it's 76.8. It's a lot
better, but it's not mind-blowing. I'm not that impressed. It's only
five years. If they're doing everything right as claimed, then I would
expect them to have a much bigger edge on couch-potato,
french-fry-hogging, soda-guzzling, tobacco-smoking, vegetable-avoiding
Americans. Americans have 450% more heart disease deaths, but Okinawans
have 25% more stroke deaths. You have to be very wary of the prejudices
of the people doing the studies, and of the prejudices reflected in the
media reporting. In the Globe article it quoted: "Never in the history
of nutrition research has the evidence been more clear and consistent. A
high-carbohydrate, low-calorie, plant-based diet is the best for
long-term health." Sounds like modern "politically correct" dietary
prejudice to me. Okinawans eat significantly *less* rice than Japanese,
significantly more protein, twice as much fish, 3 or 4 times the
vegetables, a fifth the salt and a quarter the sugar. Maybe they would
be even healthier on even less rice and even more protein, but the study
probably wouldn't even look at that. That would disagree with the sacred
food pyramid. They also didn't mention the local favorite: fried pork!
There are many aspects of the Okinawan diet that I consider excellent,
but that doesn't mean everything about it is good, and it doesn't mean
it couldn't be a lot better.

It would be very interesting to have more complete information, such as
what is called a "life table", which shows the age structure of the
entire population. You take a sample of the population born in a
particular year and make a table that shows how many die and how many
survive at each one-year step from age zero through whatever you choose,
such as a theoretical maximum of 140. The causes of death would also be
very informative, as would a report of various degenerative conditions
that didn't cause death, but caused a reduced quality of life. It sounds
like they are way ahead of average Americans on just about every health
measure, and I have some guesses as to why:

1. Fewer calories in general, and fewer sugars and starches, meaning
lower insulin response and therefore maintaining higher lifelong insulin
sensitivity. (Americans, aside from overeating, consume an average of 55
gallons of soda per year, not to mention candy bars, and the starches,
which act the same as sugar.) Insulin itself, insulin resistance, and
elevated blood sugar play a major role in probably all of our major
degenerative diseases.

2. Fewer extracted vegetable oils or hydrogenated oils, meaning fewer
inflammatory responses (which includes heart disease, among others).

3. Generally less processed food, so less oxidized cholesterol, less
salt, and less destruction of micronutrients.

4. Lots more of the anti-cancer substances in vegetables and fruits."