|
|
 |
 |
10
Causes of Obesity Other Than Overeating, Inactivity
Obesity
isn't all about eating and inactivity, says an international
group of researchers
Daniel
J. DeNoon
Just about everywhere you look, doctors
are blaming America's obesity epidemic on two things:
too much food—especially widely marketed fast food
and junk food—and too little exercise, with too much
time in front of the TV.
But we're paying too much attention to the "big two,"
argue David B. Allison, PhD, director of the University
of Alabama at Birmingham clinical nutrition research center,
and his colleagues.
"The importance of the big two is accepted as established,
and other putative factors are not seriously explored,"
they argue. "The result may be well-intentioned but
ill-founded proposals for reducing obesity rates."
To stimulate debate, Allison and colleagues suggest 10
other possible causes of obesity. Their article appears
in this week's online edition of the International Journal
of Obesity.
It's well accepted that reduced physical activity and
fast food are linked to obesity. But the evidence that
these are the main causes of obesity is "largely
circumstantial," Allison and colleagues say. Obesity
researchers should broaden their horizon, they argue.
So the researchers propose 10 other explanations for obesity,
which are also supported by circumstantial evidence.
Even if some of these causes have only a small effect,
Allison and his colleagues say, they may interact in ways
that greatly magnify their individual effects.
10
Causes of Obesity
The Alabama group puts forth these 10 "additional
explanations" for obesity:
-
Sleep
debt. Getting too little sleep can increase body weight.
Today's Americans get less shut-eye than ever.
-
Pollution.
Hormones control body weight. And many of today's
pollutants affect our hormones.
-
Air
conditioning. You have to burn calories if your environment
is too hot or too cold for comfort. But more people
than ever live and work in temperature-controlled homes
and offices.
-
Decreased
smoking. Smoking reduces weight. Americans smoke much
less than they used to.
-
Medicine.
Many different drugs—including contraceptives,
steroid hormones, diabetes drugs, some antidepressants,
and blood pressure drugs—can cause weight gain.
Use of these drugs is on the upswing.
-
Population
age, ethnicity. Middle-aged people and Hispanic-Americans
tend to be more obese than young European-Americans.
Americans are getting older and more Hispanic.
-
Older
moms. There's some evidence that the older a woman is
when she gives birth, the higher her child's risk of
obesity. American women are giving birth at older and
older ages.
-
Ancestors'
environment. Some influences may go back two generations.
Environmental changes that made a grandparent obese
may "through a fetally driven positive feedback
loop" visit obesity on the grandchildren.
-
Obesity
linked to fertility. There's some evidence obese people
are more fertile than lean ones. If obesity has a genetic
component, the percentage of obese people in the population
should increase.
-
Unions
of obese spouses. Obese women tend to marry obese men.
If there are fewer thin people around—and if obesity
has a genetic component—there will be still more
obese people in the next generation.
Will
Obesity Shorten the American Life Span?
"We
do not claim that all of the additional explanations definitively
are contributors [to obesity] but only that they are as
plausibly so as are the 'big two' and deserve
more attention and study," Allison and colleagues
conclude.
And the researchers' list of 10 doesn't exhaust the
possibilities. There may be even more explanations. Four
examples of this include: a fat-inducing virus; increases
in childhood depression; less consumption of dairy products;
and hormones used in agriculture.
|
|
|
|
