Unhealthy behaviors, rather than genes, are fueling childhood obesity, according to a study by the University of Michigan Cardiovascular Center. Overweight children are more likely to eat school lunches instead of a packed lunch and watch television or play video games for two hours a day.
“For the extremely overweight child, genetic screening may be a consideration,” said cardiologist Kim A. Eagle, M.D., lead author of the study and a director of the U-M Cardiovascular Center.
“For the rest, increasing physical activity, reducing recreational screen time and improving the nutritional value of school lunches offers great promise to begin a reversal of current childhood obesity trends.”
Obesity in children ages 6 to 11 has increased from 6.5 percent in 1980 to 19.6 percent in 2008 in the United States.
The study focused on 1,003 Michigan sixth-graders who were participating in Project Healthy Schools, a school-based program aimed at teaching students healthy habits to reduce their future risk of diabetes and cardiovascular disease.
The program can be found in 13 Michigan middle schools and is one of the few successful school-based programs proven to reduce cholesterol and high blood pressure among its students.
Fifteen percent of the participants were obese, but almost all the students, overweight or not, reported unhealthy habits.
Significantly, 58 percent of obese children had sat in front of the TV for two hours the previous day, compared to 41 percent of their healthy weight peers. Also, forty-five percent of obese students ate a school-provided lunch every day, compared to only 34 percent of healthy weight students.
Far fewer overweight children exercised on a regular basis, took a physical education class, or participated in a sports team.
Although new studies have revealed that a leptin deficiency—a genetic difference in the hormone that controls hunger—may promote overeating, researchers still conclude that lifestyle is more closely associated with obesity.
“If diets and physical activity were similar in obese and non-obese students, this would argue for a stronger genetic basis for obesity in children,” said study first author Taylor F. Eagle.
However, many of the normal weight participants also reported unhealthy habits. Overall, over 30 percent of the participants had consumed regular soda the previous day, and fewer than half could remember eating two portions of fruits and vegetables within the past 24 hours. Only one-third of participants reported exercising for 30 minutes for five days during the previous week.
“It’s clear that opportunities to improve health abound for the majority of our students, not just the 15 percent who are already obese,” said study co-author Elizabeth Jackson, M.D., assistant professor of internal medicine at the U-M Cardiovascular Center.
President Obama recently signed the Healthy, Hunger-Free Kids Act of 2010, a program designed to create healthier school menus by reducing salt, fat and sugar in cafeteria meals.
The study is published in the American Heart Journal.