Diet-related chronic diseases represent the single largest cause
of death and sickness in the United States and most Western countries.
Yet while these diseases are epidemic in contemporary Westernized
populations and typically afflict two-thirds of the adult population,
they are rare or nonexistent in hunter-gatherers and other less
Westernized cultures.
Why? There is an increasing awareness that the profound environmental
changes, such as diet and other lifestyle conditions that began
with the introduction of agriculture and animal husbandry (the care
and breeding of domestic animals), occurred too recently for the
human genome to adapt to.
Thus, universal characteristics of preagricultural human diets
are helpful in understanding how the recent Western diet may subject
modern populations to chronic disease: Before the development of
farming and the domestication of livestock practices, dietary choices
would have been necessarily limited to minimally processed wild
plant and animal foods.
It is important to understand that over
70 percent of the American diet now consists of foods that were
unavailable to preagricultrual humans, such as:
- Dairy products
- Cereals
- Refined sugars
- Refined vegetable oils
- Alcohol
Although these foods dominate the typical American diet, they would
have contributed little or none of the energy in the typical preagricultural
human diet. And while scientists and lay people alike typically
target a single dietary element as the cause of chronic disease,
evidence has indicated that virtually all so-called diseases of
civilization have many contributing dietary elements, as well as
other environmental agents and genetic susceptibility that underlie
the cause of the disease.
Consequently, these foods negatively affect proximate nutritional
factors, which collectively underlie or worsen virtually all chronic
diseases of civilization, including: glycemic load, fatty acid consumption,
macronutrient composition, micronutrient density, acid-base balance
and sodium-potassium ratio. Yet the ultimate factor underlying diseases
of civilization is the collision of our ancient genome with new
conditions of life in prosperous nations.
American
Journal of Clinical Nutrition February 2005;81(2): 341-354
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