Obesity or even being slightly overweight in middle age, a new study by Finnish researchers has found, makes people more frail in later life.
During the study of more than 1,000 men, lead author Dr Timo Strandberg and colleagues found that those who put on weight in their 40s had the highest risk of death and illness but lost it when they got older.
It is believed that the heart risk associated with middle-aged spread puts men at risk of 'frailty' even if they have no obvious illness.
For the study, the researchers followed the men from age 25 through to their 70s.
They found that those who put on weight in their 40s had a worse prognosis in middle age than those who stayed a normal weight.
However, when they examined their health in later life, a different picture emerged.
The researchers found that those who were overweight in middle age but lost weight in later life had the highest risk of death and morbidity in their 70s.
That group also had the highest cardiovascular risk in middle age.
The weight loss, which was probably not intentional, could not be explained by diseases such as cancer or heart failure.
According to Strandberg, the study indicates that the unhealthy pattern of weight in their 40s was causing frailty in later life probably due to underlying cardiovascular problems, such as high blood pressure and early stages of diabetes.
"It is important because frailty is associated with death and a great deal of disability," the BBC quoted him as saying.
The research is published in the European Heart Journal.