The findings showed that the premature deaths, defined as those at ages 35-69 years, would be 29.5 per cent and 14.6 per cent for moderately obese men and women.
This corresponds to an absolute increase of 10.5 per cent for men, and 3.6 per cent for women, which is three times as big, as the risk of premature death in men with normal Body Mass Index (BMI) is at 19 per cent and women at 11 per cent.
The risk was found to increase steadily and steeply with the rise in BMI, the researchers said.
“The study found that men who were obese were at much higher risk of premature death than obese women. This is consistent with previous observations that obese men have greater insulin resistance, liver fat levels, and diabetes risk than women,” said lead author Emanuele Di Angelantonio from the University of Cambridge in Britain.
Further, an increased risk of premature death was also found for people who were underweight.
Overweight or obese people also are at high risk of developing coronary heart disease, stroke, respiratory disease and cancer, said the paper published in the journal The Lancet.
“On average, overweight people lose about one year of life expectancy, and moderately obese people lose about three years of life expectancy,” Angelantonio added.
According to World Health Organisation (WHO) estimates 1.3 billion adults worldwide are overweight and a further 600 million are obese.
“Obesity is second only to smoking as a cause of premature death,” noted one of the researchers Richard Peto, Professor at University of Oxford, in Britain, adding that “smokers can halve their risk of premature death by stopping.”
For the study, the team followed 39,51,455 participants (69 per cent women), all aged between 20 and 90 years old. Out of these 3,85,879 died. The analysis is of those who then survived at least another five years.