2010-09-01 11:20:41
Tue Aug 31, 9:44 pm ET
WASHINGTON (AFP) Physical exercise can reduce a genetic predisposition to
obesity by an average of 40 percent, a new study showed.
The research challenges the notion that an inherited propensity to obesity is
impossible to overcome and boosts the case for the benefit of more exercise for
anyone looking to shed some weight.
The study, published in this week's Public Library of American Science Medicine
journal, is based on examination of 20,430 people living in Norwich, Britain.
It found most of the study's participants inherited between 10 and 13 genetic
variants known to increase the risk of obesity, with some inheriting as many as
17 variants, and others as few as six.
Using modelling techniques, the researchers found that each genetic variant was
linked to an increase in body mass index (BMI) -- a measure of body size based
on both height and weight.
"Each additional genetic variant in the score was associated with an increase
in BMI equivalent to 445 grams (1.6 ounces) in body weight for a person 1.70
meters (5.7 feet)," the study said.
For physically active individuals, the increase was just 379 grams (13 ounces).
That was "36 percent lower than in physically inactive individuals in whom the
increase was 592 grams (21 ounces) per variant," the research found.
Each additional variant also raised the individual's chances of obesity
1.1-fold, but in physically active individuals, "the increased odds per variant
for obesity risk were 40 percent lower."
Ruth Loos of Britain's Medical Research Council Epidemiology Unit, who carried
out the research, said the study "challenged deterministic view of the genetic
predisposition to obesity."
"Our findings further emphasize the importance of physical activity in the
prevention of obesity," Loos said.