Wired for Weight Problems? Researchers Reveal Influence, Limitations of 'Obesity Gene'

By Hugh C. McBride

As the news spread that researchers had discovered an "obesity gene," responses ranged from relief ("I knew this wasn't because I wasn't working hard enough") to remorse ("Great - now there's no chance I'll ever lose this weight").

But as additional analysis of the relationship between genetics and obesity has come to light, it appears as though neither of these reactions were entirely justified. Although the presence of certain genes does appear to increase the likelihood that a person will have weight problems, ample evidence exists that this genetic predisposition can be offset or overcome.

The Obesity Gene
The initial discovery of what came to be called the obesity gene (actually a variant, or an allele, of the FTO gene) was announced in Science magazine in April 2007.

After analyzing data from more than 38,000 subjects, researchers from the United Kingdom's Peninsula Medical School and Oxford University discovered that individuals with two copies of the "fat" version of the FTO gene had a 70 percent higher risk of becoming obese than did those who had no copies. People with two copies of the obesity-related FTO allele were also found to outweigh non-carriers of the allele by an average of 6.5 pounds.

In an April 12, 2007 article on the BBC News website, Peninsula professor Andrew Hattersley said that the study indicated diet and exercise aren't the only factors that influence a person's weight.

"The typical message has been that if you are overweight it is due to sloth and gluttony and it is your fault," Hattersley told the BBC. "This work is suggesting that there is also a genetic component."

More Genes, More Information
Nineteen months after the initial reports of the relationship between the FTO allele and obesity, an article in the Financial Times reported that researchers have now identified eight additional weight-related genetic variants.

Of particular interest to both scientists and weight loss experts is the fact that the majority of the genes that have been identified as influencing obesity all appear to affect the brain rather than the body's metabolism or energy storage capabilities. Thus, these genes seem to influence appetite and desire for food, rather than the body's ability to process that food once it has been eaten.

"This suggests that, as we work to develop better means of combating obesity ... we need to focus on the regulation of appetite at least as much as on the metabolic factors of how the body uses and stores energy," Kari Stefansson told FT writer Clive Cookson. Stefansson is the chief executive of deCode Genetics, one of the companies that has been at the forefront of the effort to identify and understand the role of genetics in obesity.

'Not Doomed by Genes'
Though recent research has expanded our understanding of the biological nature of obesity, this doesn't mean that previously held beliefs (such as the power of diet and exercise) have been rendered obsolete. In fact, researchers with the University of Maryland Medical Center (UMMC) have determined that lifestyle choices can offset a genetic predisposition to obesity.

According to a Sept. 8, 2008 article in the journal Archives of Internal Medicine, a UMMC team led by Soren Snitker, M.D., Ph.D., that studied the members of Lancaster, Pennsylvania's Old Order Amish population found that those who engaged in regular physical activity were able to maintain healthy weight, even though they have a genetic variation that makes them prone to obesity. Because the Old Order Amish eschew many modern conveniences and technological advances, their agrarian lifestyle demands considerable physical activity.

"The studies show that if you have two copies of the gene and you're incorporating physical activity in your daily life, you're less likely to become obese, Evadnie Rampersaud, the study's lead author, said in a Sept. 9, 2008 post on the Los Angeles Times health blog.

Rampersaud and her colleagues also reported the following:

• Human obesity is a multifactorial syndrome influenced by genetic, physiological, behavioral, and socio-cultural factors.
• The UMMC study's results strongly suggest that the increased risk of obesity due to genetic susceptibility can be blunted through physical activity.
• The study shows that a high level of physical activity can 'level the playing field,' equalizing the risk of obesity between those who have copies of the FTO gene variant and those who don't.

Stay Active, Stay Healthy
Regardless of one's genetic makeup, eating a nutritious diet and getting adequate amounts of exercise remain the key components of maintaining a healthy weight. 

Being active doesn't mean that you have to follow the Amish example and spend hours plowing the fields - in fact, if you've been relatively sedentary for a while, you can still find creative and safe ways to incorporate more movement into your days.

And when you're done with your workout, spend a few moments learning how to prepare delicious and nutritious meals. In addition to helping rid yourself of unwanted weight, your newfound kitchen skills will help reduce your food budget and increase your sense of self-reliance, self-worth, and self-esteem.

Taking control of, and responsibility for, your diet and exercise decisions will hopefully remind you that when it comes to determining the quality of the life you will lead, genetics are just the blueprint. You're the one who is responsible for what ultimately gets built.