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Each vegan saves 1.5 tons of CO2/year

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  • Trisha
    Each vegan saves 1.5 tons of CO2/year http://tinyurl.com/rp9wl (pdf file 30 + pages) Gidon Eshel and Pamela Martin of the University of Chicago compared the
    Message 1 of 1 , Apr 30, 2006
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      Each vegan saves 1.5 tons of CO2/year

      http://tinyurl.com/rp9wl (pdf file 30 + pages)

      Gidon Eshel and Pamela Martin of the University of Chicago compared
      the amount of fossil fuel needed to cultivate and process various
      foods, including running agricultural machinery, providing food for
      livestock and irrigating crops. They also factored in emissions of
      methane and nitrous oxide produced by cows, sheep and manure
      treatment.

      The typical US diet, about 28 per cent of which comes from animal
      sources, generates the equivalent of nearly 1.5 tonnes more carbon
      dioxide per person per year than a vegan diet with the same number
      of calories, say the researchers, who presented their results at a
      meeting of the American Geophysical Union in San Francisco.

      Based on a total gross caloric consumption of 3774 Kcal
      person−1
      day−1, of which 1047 Kcal, or 27.7%, are animal-based. Of
      those 1047
      Kcal day−1, 41% are derived from dairy products, 5% from eggs,
      and
      the remaining 54% from various meats. For comparison, we let all
      diets, including the exclusively plant based one ("vegan"), comprise
      the same total number of gross calories, 3774 Kcal day−1.

      The estimated energy efficiency of protein in animal products varies
      from 0.5% for lamb through 5% for chicken and milk to 3% for beef
      (second column of Table 2). This wide 6 range reflects the different
      reproductive life histories of various animals, their feed, their
      genetic ability to convert nutrients and feed energy into body
      protein, fat and offsprings, the intensity of their rearing, and
      environmental factors (heat, humidity, severe cold) to which they
      are subjected, among other factors. Accounting for the total energy
      content relative to the energy from protein, these numbers translate
      to roughly 1%, 20% and 6% . The weighted mean efficiency of meat
      [red meat (consisting of beef, pork and lamb), fish and poultry] in
      the American diet is 9.32% . These efficiencies are readily
      comparable with the energy efficiency of plant-based foods: 60% for
      tomatoes, 170% for oranges and potatoes, 500% for oats.

      The perhaps surprising and notable equality of fish and red meat
      low efficiencies reflects (1) the large energy demands of the long
      distance voyages required for fishing large predatory fishes such as
      sword and tuna toward which western diets are skewed, and (2) the
      low energetic efficiency of salmon farming.

      The thrust of this paper has been that the U.S. bears a GHG burden
      for the animal-based portion of its collective diet. From Fig. 3 we
      can estimate this burden as roughly 1.485 ton CO2-eq person−1
      yr−1×
      291 million Americans 432 million ton CO2-eq yr−1
      nation-wide, or
      approximately 6.2% of the total [6,9335.7 million ton CO2-eq in
      2003].

      This report them raises the question of whether a plant-based diet
      is nutritionally adequate for public health and concludes that the
      available evidence suggests that plant-based diets are safe, and are
      probably nutritionally superior to mixed diets deriving a large
      fraction of their calories from animals.
      The adverse effects of dietary animal fat intake on cardiovascular
      diseases is by now well established . Similar effects are also seen
      when meat, rather than fat, intake is considered. Less widely
      appreciated-despite being just as persuasively demonstrated,
      exhaustively researched and robustly reproducible-are the links
      between animal protein consumption and cancer (for a thorough
      review, see the pdf).

      The first studies linking dietary animal protein and cancer focused
      on cancer initiation, the brief process during which cancercausing
      mutations first occur. Collectively, they documented numerous
      cellular mechanisms by which cancer initiation increases under high
      animal protein diets. Followup studies addressed cancer promotion
      after initiation, showing dramatically increased pre-cancerous
      deformities in response to a given carcinogen dose under high animal
      protein diets. To unambiguously implicate animal protein in the
      observed enhanced cancer promotion, induced carcinogenesis under
      high protein diets of animal and plant origins was studied. Cancer
      promotion was significantly enhanced under animal-protein-rich diet.
      Extending these results to clinical cancer (as opposed to cancer
      precursors), showing roughly an order of magnitude higher tumor
      incidence in rats on high animalprotein diets who lived their full
      natural life-span. Similar results were also obtained with different
      species and carcinogens. Note that the above laboratory results were
      all obtained at protein intakes per unit body mass routinely
      consumed by Westerners, suggesting the applicability of the results
      to humans. Plus, human epidemiological evidence indeed corroborates
      the link between animal-based diet and cancer. For example, Larson
      et al. show enhancement of ovarian cancer with dairy consumption in
      Swedish women; Sieri et al. show a strong association between animal
      protein intake and breast cancer in Italian women; Chao et al. show
      a tight positive relationship between meat consumption and
      colorectal cancer; and Fraser demonstrates a halving of colon and
      prostate cancer risk among vegetarians. Barnard et al. documented
      the disease burden exerted by seven major diseases on the health
      care system directly related to meat consumption. The conclusion,
      reached by, e.g., Sabate, that animal-based diets discernibly
      increase the likelihood of both cardiovascular diseases and certain
      types of cancer. To our knowledge, there is currently no credible
      evidence that plant-based diets actually undermine health; the
      balance of available evidence suggests that plant-based diets are at
      the very least just as safe as mixed ones, and most likely safer.




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