Keep it lean for longer life
Being lean - but not too thin - is the recipe for a long life, according to researchers.
While an Australian National University study has dismissed some suggestions that being overweight helps people live longer, it also found that being in the middle to higher end of the normal weight range was the ideal.
Current guidelines recommend people have a body mass index - calculated by dividing weight by height squared - of between 18.5 and 24.9, while 25 to 30 is considered overweight, and anything over that is obese.
The study found that the best BMI for a long life was 22.5 to 24.9, because those on the lower end of the normal weight range tended to include people who smoked to control their weight or had an ongoing medical condition.
Researchers followed more than 246,000 Australians from the Sax Institute's 45 and Up Study to see how their risk of death varied over a four-year period according to their BMI.
They were trying to tease out why earlier research had found that being overweight improved life expectancy and concluded that the research was flawed because it did not take into account that some people with low weight had chronic diseases or smoked, so were less likely to have a longer life than overweight people.
When the results were adjusted for this, researchers found death rates were higher in the overweight and obese, and lowest in people with a BMI between 22.5 and 24.9.
The National Heart Foundation described the results as an inconvenient truth for overweight Australians.
Director of cardiovascular health Robert Grenfell said the study helped clear up confusion about the health impact of being overweight, finding it was a myth that it aided longevity.
"Society has normalised obesity, which has given people who are overweight or obese a false sense of comfort," he said.
"If your BMI is outside of the healthy range, you are at greater risk of heart disease and this risk increases exponentially with the more overweight you are."
