Genes Stacked Against Weight Loss?

Jan. 18, 2008 -- If weight loss was one of your New Year's resolutions, don't expect your genes to get you to your goal.

In a new report, scientists estimate that more than 6,000 genes affect weight in mice.

Though those findings came from studies of mice, they may have meaning for people, notes researcher Michael Tordoff, PhD, of Philadelphia's Monell Chemical Senses Center.

"Reports describing the discovery of a new ' obesity gene' have become common in the scientific literature and also the popular press," Tordoff says in a news release. "Our results suggest that each newly discovered gene is just one of the many thousands that influence body weight, so a quick fix to the obesity problem is unlikely."

Searching for Weight Genes

Tordoff's team reviewed previous studies of some 1,900 mouse genes. Most of those genes didn't affect the mice's weight, but 31% could boost weight and 3% could cut weight.

In other words, weight-gain genes outnumbered weight-loss genes by 10 to one, "which might help explain why it is easier to gain weight than lose it," Tordoff says.

The researchers' estimates appear online in BMC Genetics. But there's more to weight than genetics -- for mice and for people.

Take diet, for instance. Eat more calories than you burn and your genes can't bail you out of weight gain forever.

And then there's physical activity. Sitting on the sidelines isn't going to get extra weight off, whether you're a person skipping your workout or a mouse with no running wheel in your cage.

The bottom line? You can't change your genes, but you can work on eating healthfully and being more active. Genes aren't the whole story, even if there are thousands of them involved.