Born to Be Obese?

May 29, 2008 8:46:23 PM PDT
Are we wired to be thin or overweight?Growing research shows genes can play a role.

The science behind our cravings could help explain why Americans are getting bigger. Sixty-six percent of adults in the U.S. are overweight as are 17 percent of this country's children. Overeating and lack of exercise seem to be the biggest culprits, but discoveries in the lab may help explain why, for some people, staying trim seems almost impossible.

Obesity - is it a disease just like any other? Is it a lifestyle filled with bad choices? Or is it simply predetermined at birth? Jeannette Standard said she believes she's proof the genetic connection is real.

"I always figured I got it from my parents 'cause Daddy was overweight, Mamma was heavier than what she should have been," Standard said.

Her battle began early. She weighed 150 pounds in fifth grade, 180 when she started high school and 250 by the time she got married. At 30, that number doubled. Then it doubled again. Her heaviest was 1,200 pounds.

Weight may be determined by something more than a love for food. It may actually start at conception. Scientists now know of several genes that seem to influence obesity. The FTO gene is one of them.

"If you do have the FTO gene, it does put you at risk for becoming obese and having type 2 diabetes and extra body fat," said Emily Rubin, RD, weight loss dietitian.

In another find, researchers from the University of Florida discovered at least 11 genetic mutations that cause a receptor to malfunction. That receptor controls the appetite suppressing hormone leptin. And even more research reveals impaired dopamine levels may make people more likely to overeat.

"It's very exciting to try to start to pin down what might be different possible causes for the obesity at least in some patients," said Dr. Siri Atma Greeley, pediatric endocrinologist, University of Chicago Medical Center.

Just recently at the U of C Medical Center, researchers found in a Chicago mother and her 10-year-old son another rare genetic mutation that appears to slow metabolism.

"Essentially he would have to eat less to get the same energy out of his food than someone else," said Greeley.

Geneticist Nancy Cox said she thinks the real value in uncovering these genes is gaining a better understanding of the biological process that leads to weight gain so people can lose weight and keep it off.

"Frankly, it's not so easy to change our genes but we can change our environments and that's also one of the things we will start to see from these studies," said Cox, a geneticist at U of C Medical Center.

Researchers say early intervention is key and the first few years of a child's life are critical, especially if they come from a family of large waistlines.

"They are born with a certain number of genes they inherit and then during their development, they have genes that will either turn on or turn off depending upon their environment and depending upon what behaviors they are allowed to participate in," said Melinda Sothern, Ph.D., exercise physiologist, Louisiana State University.

Getting parents to alter eating and exercise habits could help protect children from their genetic risks. Standard's lost more than 800 pounds but worries she's passed her weight problem on to her children. She just hopes they'll learn how to reverse the trend before it's too late.

Losing weight can be a lifelong battle. Only one-third of morbidly obese people are able to keep the weight off for more than a year. Exercise is key at any age.

In fact, studies show how much physical activity children are exposed to in the first three years of life has a lot to do with whether they become overweight children and obese adults.


Load Comments