Gene May Make Kids Crave Junk Food

WEDNESDAY Dec. 10, 2008 -- Some people may be genetically driven to seek out more calorie-dense foods, a new study suggests.

In the Dec. 11 issue of the New England Journal of Medicine, British researchers report that children with a particular gene variant tend to eat more energy-dense foods, which means food with more calories per weight. However, the researchers didn't find any difference in metabolism between kids with the gene change and those without it.

"What [this study] effectively shows is that people with the relevant variants on the gene have a trait which may lead them to eat more unhealthy, fattening foods," study senior author Colin Palmer, chairman of pharmacogenomics in the Biomedical Research Institute at the University of Dundee, said in a news release. "I would stress that this is a trait, and not an absolute occurrence."

Dr. Goutham Rao, clinical director of the weight management and wellness center at Children's Hospital of Pittsburgh at the University of Pittsburgh Medical Center, said he thinks these findings are "hopeful" because the researchers didn't find a difference in metabolism.

"The way genes influence obesity is through behavior, rather than metabolism. That means this is something you can work on. And, the good news is that a lot of the kids who had the gene weren't overweight," he said.

More than 16 percent of U.S. children are currently obese, according to the U.S. Centers for Disease Control and Prevention. As those children grow up, the statistics are even more grim -- 35 percent of adults are considered obese, according to the CDC.

The new study builds off past research that identified a variant in the FTO gene that is associated with obesity. The researchers measured the height and weight of 2,726 Scottish children between the ages of 4 and 10. They also performed genetic testing on saliva samples from the children to assess whether or not they had changes in their FTO gene.

The researchers found that having change in the FTO gene was associated with increased weight and body-mass index scores.

From the larger group, the researchers studied the eating habits of 97 children. They also measured how much energy these children expended, and found no difference in the resting energy expenditure rate for kids with the genetic change compared to those without it.

Where they did find a difference, however, was in the number of calories consumed. The children were given a variety of options to eat, such as ham, cheese, raisins, grapes, cucumber, carrots, chocolate, water, orange juice and bread rolls. The researchers measured what the children ate on three different occasions.

Children with the variant gene consumed about 100 calories more per meal, even though the weight of the food consumed was nearly the same. While 100 calories may not seem like much, that many extra calories per meal would translate to an extra pound of weight about every 12 days.

"These findings do not change the dietary and lifestyle advice to people, which would be to eat relatively healthily and take regular exercise," said Palmer. "But, these findings do also reinforce the hypothesis that the increase in obesity seen in children over recent years may be largely attributable to the widespread availability of inexpensive and highly energy-dense foods, which may be more attractive to the large proportion of the population who carry this genetic variant," he noted.

Rao said the important message from this study is that prevention is key. "If you have a child, whether they're overweight or not, if they have a predilection for seeking junk food, you need to intervene. The emphasis should be on portion control. If you restrict a food completely, the message children get is that there's something special about that food, and then they're going to overindulge when they do get it."

More information

The U.S. Centers for Disease Control and Prevention has tips on keeping your child at a healthy weight.

Posted: December 2008


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