NOVEL THEORY CONNECTS MOTHER'S TO CHILDHOOD OBESITY
As the waistlines of children in the United States continue to grow,
scientists continue to seek causes of the childhood obesity epidemic. One
University of Alabama at Birmingham School of Public Health researcher has
published a new theory that he says explains why infants in the United States
are being born heavier than at any time in our nation's history.
According to the
Centers for Disease Control and Prevention, obesity has more than doubled in
children and quadrupled in adolescents in the past 30 years. In 2012, more than
one-third of children and adolescents were overweight or obese.
"Childhood obesity
is the major public health problem of the 21st century and will continue to be
until we fully understand why children are becoming obese. My theory offers
that understanding," said Edward Archer, Ph.D., postdoctoral fellow in the
Nutrition Obesity Research Center and Office of Energetics.
Archer says that
previously there were no valid theories as to why children are becoming so
obese so rapidly, and that the common notion of "moving too little and
eating too much" is simplistic and leads to the stigmatization of a large
portion of our population.
Through a
meta-theoretic analysis, Archer unified ideas from a number of scientific
fields and created a grand narrative, "The Childhood Obesity Epidemic As a
Result of Non-Genetic Evolution: the Maternal Resources Hypothesis,"
published in the November issue of the Mayo Clinic Proceedings.
"This paper is a
significant advance in the theory and science of evolution, obesity and
health," Archer said. "It synthesizes a century of evidence from
fields as diverse as pediatrics, evolutionary biology, anthropology and
epidemiology to present a novel theory on the causes of the childhood obesity
epidemic."
There are three main findings:
1. Obesity is the result of fat cells'
out-competing other tissues for the energy consumed through food.
2. A woman's physical activity and body
composition before, during and after pregnancy have evolutionary consequences
because both determine not only her metabolism and risk of disease but those of
her children, grandchildren and great-grandchildren.
3. Mothers in many subpopulations have evolved
past a "metabolic tipping point" that makes obesity and poor physical
fitness almost inevitable for their children and their children's children.
"My theory says
that obesity is the result of nongenetic evolutionary forces, for example
social/cultural evolution, that have led to the competitive dominance of fat
cells," Archer said. "Beginning in the 1960s, mothers became
increasingly physically inactive, sedentary and heavier. This altered their
bodies' metabolism during pregnancy. With less competition between fat and
muscle cells due to inactivity, more energy was available to increase the
number of fat cells in their unborn children. The result was a dramatic
increase in the risk of obesity and disease in infants and children."
Archer says these
findings demonstrate that the typically highlighted reasons for childhood
obesity are not the root cause, and the issue began with earlier generations.
"My paper
demonstrates that gluttony and sloth are not the primary determinants of
obesity, and hopefully it will dispel the ignorance that causes good-hearted
people to mistakenly think that a child is obese because of a lack of
willpower, or because his or her mother does not care enough to provide proper
food," Archer said. "Willpower and good intentions cannot compete
with evolution."
To halt the continued
evolution of obesity, Archer says would-be moms must be physically active
throughout their lives -- especially during puberty -- to prepare their metabolisms
for pregnancy and have metabolically healthy children. Archer thinks that
clinicians must know that preconception and prenatal exercise are essential but
underutilized tools in the struggle against obesity.
"Evolution is the
cause, and active moms are the cure," Archer said. "Only mothers have
the power to change the evolution of obesity."
In hopes of developing
effective interventions based on his theory, Archer is building virtual humans
-- including pregnant women -- via computational modeling.
"Science can
improve the lives of mothers and children, and my theory is a productive first
step," Archer said.
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