Don't kid yourself if you're fat but otherwise fit. Excess weight could make you sicker later in life and might even kill you someday, researchers said. 

People who were overweight or obese in middle age but did not have health problems were at much higher risk of dying from heart disease or diabetes after age 65 than normal-weight people, said the study published in this week's issue of the Journal of the American Medical Association. 

"Even for those who didn't have high blood pressure, high cholesterol or diabetes -- but who were overweight or obese in middle age -- were at much higher risk of being hospitalized for heart disease or diabetes or even dying from it in older age," said Lijing Yan, lead author of the study by researchers from Northwestern University in Evanston, Illinois. 

"Every pound (kg) that you put on really does rob you later on in life of health, as well as (increases the) chances you're going to be hospitalized more, and perhaps even die sooner," said fellow researcher Robert Kushner. 

The researchers sought to dispel the notion that overweight people need not worry as long their blood pressure and cholesterol levels were normal. 
The study initially evaluated 17,643 men and women aged 31 to 64, then tracked their health for more than three decades. They were divided into risk categories based on whether their blood pressure and cholesterol levels were above or below certain thresholds, and whether they were smokers. 

People who had been obese at midlife but were otherwise healthy were 43 percent more likely to die from heart disease and 11 times more likely to die from diabetes after age 65 than normal-weight people. 

Among those at moderate risk who previously had markers for heart disease like high blood pressure, obesity more than doubled their risk of dying from the disease compared to normal-weight people. 

Obesity affects about 300 million people worldwide. Based on a calculation involving height and weight, a body mass index of 30 or greater is considered obese.