RE: evolution and diet (was: FITNESS: Diet and Exercise)

From: Ramez Naam (mez@apexnano.com)
Date: Wed Apr 16 2003 - 12:00:45 MDT

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    From: Brian Atkins [mailto:brian@posthuman.com]
    > Here is quote from an old 1950's diet book I was browsing:
    >
    > "In 1921 coronary thrombosis was a rarity and accounted for only 746

    > male deaths in Britain. In 1956 the figure was 45,000. It is
    > still going up."

    Hmmm. I simply do not believe that statistic. It's inconsistent with
    other data from that time period. For example in the US in 1921,
    137,000 people died of heart disease, out of a total of about 1
    million deaths in the US that year.

    Let me summarize the CDCs statistics for US causes of death in 1921.
    In descending order of incidence:

    CAUSE % of ALL DEATHS
    Heart Disease 14%
    Pneumonia 9%
    Tuberculosis 9%
    Stroke 8%
    Cancer 7%
    Nephritis 5%
    Accidents 5%
    Diarrhea & enteritis 4%
    Premature birth 4%
    Diphtheria 1-2%

    These stats are available at
    http://www.cdc.gov/nchs/data/statab/lead1900_98.pdf

    What they suggest to me is about what I'd expect. In 1921 the US was
    in a transition from the pre-1900 period (when infectious disease was
    responsible for most deaths) to the late 20th century (when
    age-related problems were responsible for most deaths).

    Note that life expectancy in 1921 US was somewhere in the low 50s.

    This is consistent with a model where the conquering of infectious
    disease has allowed humans to live longer and, for the first time,
    experience the problems of old age such as heart disease and cancer.

    > So I don't believe the argument that we
    > are only seeing this huge rise in that set of diseases because we
    are
    > living longer is accurate. In 1920 people over 50 simply _did not_
    > suffer from heart attacks very often at all. Something
    > changed in just a few short decades to make this a much more
    > common event, and so far science has not figured it out.

    Well, in the US between 1920 and 2002, heart disease has gone from
    causing 14% of all deaths to 50% of all deaths. But incidence of
    infectious disease deaths has dropped almost to zero, and life
    expectancy has increased by more than 20 years. So that doesn't seem
    to hard to explain.

    Also note that infectious diseases are particularly dangerous not only
    to the very young, but to the old, the very same people at risk of
    heart disease and cancer! Now that we've effectively conquered
    infectious disease in the US it doesn't matter, but if you look at the
    pattern of death by age in earlier civilizations you'll find that the
    old died of infectious diseases much more frequently than young or
    middle-age adults.

    At the same time, I completely agree that lifestyle factor are also to
    blame for an increased incidence of heart disease. Americans in 2002
    consume more total calories, more fat, and more sugar than at any
    point in last few centuries. They also live an unprecedented
    sedentary lifestyle.

    So, put all of this together and I don't see why you say that science
    hasn't figured out why heart disease has become the leading killer.

    > It very well could be due to dietary changes- most of which
    > were shifts away from eating traditional/natural foods.

    By traditional/natural do you mean pre-agrarian? If so, I doubt you
    could find much evidence of that in the early 1900s.

    mez



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