WASHINGTON -- Researchers have produced the first clear evidence for a gene common in the population that dictates why some people gain excess weight while others do not.
They found the gene, called FTO, by studying nearly 39,000 white Europeans in a finding they hope can lead to new ways to fight this growing global health problem.
British researchers, writing in the journal Science published yesterday, said the presence of a version of FTO increased a person's risk for obesity, and it was very common in the people studied -- 63 percent had one or two copies of it.
People with two copies had about a 70 percent higher risk of being obese than people with none and were an average of nearly 7 pounds heavier than a similar person with no copies. Those with one copy had a lesser but still elevated risk.
Genetics has long been assumed to play a role in making some people fatter than others, and previous research had tentatively implicated specific genes.
The researchers emphasized, however, that genetics alone cannot fully account for a worldwide surge in obesity in recent decades. Public health analysts have attributed the phenomenon to multitudes of people eating too much of the wrong foods and getting too little exercise.
Obesity is recognized as a growing public health problem worldwide. Obese people are at greater risk for diabetes, heart disease, stroke, high blood pressure, and some cancers.
The researchers said that while improving one's lifestyle is still the key to reducing the obesity epidemic, their findings explain why some people will find it harder to change their weight than others : because of their genes.
Researchers led by Andrew Hattersley of Peninsula Medical School in Exeter and Plymouth and Mark McCarthy of the University of Oxford examined the genetics of nearly 39,000 children and adults from Britain, Finland, and Italy.