Researchers have discovered that there is a genetic tendency to obesity. Jean-Paul Chassenet / TNS
Mari A. Schaefer
Some people who are overweight report that they eat no more than slim friends and exercise so much, but still can not lose weight.
Researchers now think they know why this experiment is entirely possible, an explanation they hope to help de-stigmatize obesity and offer new avenues to avoid a condition linked to killers, including cancer, in ever-younger Americans.
Scientists at the Broad Institute of Massachusetts Institute of Technology and Harvard University have discovered that there is a genetic tendency for obesity. The results were published Thursday in the journal Cell.
"We have known for a long time that some people are born with DNA predisposing them to obesity," said study lead author Amit V. Khera, a cardiologist at the Massachusetts Center for Genomic Medicine in a statement.
"Now we can quantify these differences significantly and potentially explore new routes to achieve better health."
"We have known for a long time that some people are born with DNA predisposing them to obesity.
Obesity is a major global health problem. Nearly 40% of US adults and about 18.5% of children are considered obese, according to the Centers for Disease Control and Prevention.
The researchers analyzed published data on how more than 2.1 million places in the genome affect body weight.
They distilled the information into a single score for each individual. They validated the score by comparing it with data from nearly 120,000 people in several large-scale studies, including the UK's Biobank, an open access database of health information collected from half a million participants and used for research. They found that 10% of the adults with the highest scores were 25 times more likely to be severely obese compared to those with the lowest scores.
"There is a golden period of intervention that can reduce the risk of obesity and that period is childhood.
"Your susceptibility to obesity is based on the variants you inherited from your parents," said researcher Sekar Kathiresan, director of the Cardiovascular Disease Initiative at Broad Institute, in a press release.
But Kathiresan also said that genetics does not necessarily command its weight – although some people really need to work harder than others to be lean.
When researchers compared the weight of those who had a hereditary risk for obesity and those who were not between 18 and 50 years old, they found that there was a difference of 30 pounds on average. But when they observed the birth weights of the two groups, there was no difference, he said.
The inherited difference in weight gain begins to appear when people are about three or four years old, Kathiresan said.
"There is a golden period of intervention that can reduce the risk of obesity, and that period is childhood," he said.
But even after childhood, exercise and proper nutrition can change the risk that comes from inheritance, Kathiresan said.
The results of the research give more information about the biology of obesity and why some people remain lean. Studying lean people can help develop new treatments to help others avoid being overweight, Kathiresan said.
"We're hoping this research really detigmatize obesity," he said.
The study looked mainly at people of European descent. Additional research is needed on different ancestral origins, researchers said.
Tribune News Service