For your reading pleasure....And just to throw water on the oil-soaked fire that Waco and Aloft started :buck:
This is an exerpt from: GASTROENTEROLOGY 2007;132:2087–2102
"Throughout history, considerable effort has been devoted
to finding ways to improve the adequacy and stability
of the food supply and to reduce the energy expenditure
required for work. As a result, an organism
adapted for a situation in which food was limited and
physical exertion was required now often is confronted
with an environment in which palatable energy-dense
foods are obtained easily with minimal physical activity.
129,130 Increased modernization and a Westernized diet
and lifestyle are associated with an increased prevalence
of overweight in many developing countries. This sometimes
has been referred to as the nutrition transition or part
of a transition to modernity.
131 There is little evidence,
however, of a point at which this process ceases.
The factors that determine body weight and body
composition in the absence of major environmental constraints
are not well understood.
132 Energy intake and
energy expenditure, the ability to store excess fat under
conditions of overfeeding and the ability to lose fat under
conditions of underfeeding, all appear to have genetic
elements.
133–136 Genetic factors, however, are unlikely to
explain the current increases in the prevalence of overweight
and obesity occurring in the United States, the
United Kingdom, and many other countries.129,130 Surprisingly
little is known about these increases in overweight
and obesity. Clearly, individual behaviors along
with social, cultural, and environmental factors also must
play important roles. It is likely that a gene-environment
interaction, in which genetically susceptible individuals
respond to an environment with increased availability of
palatable energy-dense foods and reduced opportunities
for energy expenditure, contributes to our current high
prevalence of obesity. Reductions in physical activity and
changes in energy intake contribute to these but are
difficult to measure.
137,138"
If you REALLY want, here's the whole paper: <cite>nchspressroom.files.wordpress.com/2007/07/gastropaper.pdf
And, to really bore you even more here's another article:
http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1629353&pageindex=1#page
</cite>