According to a new study, scientists have found that the genes of a person can help predict how much weight a person will lose after a gastric bypass surgery.

One third of the American population is known to be obese and many of the people opt for gastric bypass surgeries to lose those extra pounds. The level of success is not guaranteed in these surgeries. However, a group of researchers from Massachusetts General Hospital and Harvard Medical School has found that the genes of a person can help predict how much weight one sheds after a successful weight loss surgery.

"Surgery is the most effective therapy for severe obesity, but these procedures are invasive, and not all patients get the same degree of benefit," said senior study author Lee Kaplan of Massachusetts General Hospital and Harvard Medical School. "If we can identify those patients who are likely to lose more weight after surgery from those who do less well, we could help steer patients towards the therapy that best suits them."

During such surgeries, a person loses about 35 to 40 percent of the initial weight and manages to keep this weight off the body even after the surgery. However, the results are different for different people and sometimes this difference is enormous. Researchers have still not been able to find the reason for this disparity in loss of weight among people.

To determine whether genetic factors play a role in this phenomenon, the team of researchers examined the genomes of more than 1,000 individuals undergoing gastric bypass surgery.

They discovered that people with two copies of a specific variant on chromosome 15 generally lost about 39 percent of their body weight during such surgeries while individuals with no copy of this variant lost less than 30 percent of their body weight through the surgery.

"This is the first instance where a genome-wide search has identified genetic predictors of weight loss after gastric bypass surgery," Kaplan said. "Since the genes identified in this report have not previously been known to be involved with body-weight regulation and obesity, their identification may suggest new approaches that could be used to develop novel therapies for obesity, diabetes, and related metabolic disorders."