It was, given its timing, unexpectedly good news: as thousands began new year diets, US researchers reported that being overweight could extend your life.
But rather than celebrate, medical experts yesterday tried to pour cold water on the findings – exactly as the chief author of the study, Katherine Flegal, predicted they would.
Dr Flegal, from the National Centre for Health Statistics in Maryland, and her team reviewed almost 100 studies of the link between weight and mortality, involving nearly three million people.
Their findings, published in the 'Journal of the American Medical Association' (JAMA), showed those who were overweight (with a Body Mass Index of 25 to 30) and those who were mildly obese (with a BMI up to 35) had a 5 to 6pc lower chance of dying prematurely than "normal weight" individuals (18.5 to 25 BMI).
Professor Nick Finer, of University College Hospital, said BMI was an "imperfect measure" which depended on additional factors such as blood pressure and cholesterol.
Professor Stephen O'Rahilly, of the University of Cambridge Metabolic Research Laboratories, said: "The lack of adverse effects on mortality of mild obesity and the apparent slight reduction in death rate . . . should not be taken to mean that such states are not likely to be harmful to health."
The results show only the severely obese have a significantly increased mortality, up by 29pc. Otherwise, extra weight appears to be protective. Underweight people, meanwhile, have a 10pc higher rate of premature death than those of normal size, according to earlier research.
"There is already a lot of literature showing that being overweight is linked with lower mortality," said Dr Flegal.
"It is not an unusual finding. But authors tend to shy away from it. They tend to underplay it or try to explain it away." (© Independent News Service)