Husband and wife team Leonid and Natalia Gavrilov, from the Centre on Ageing at the University of Chicago looked at the health records of dozens of centenarians to determine why they had lived so long.
They found that not eating too much, but also not eating too little, was the crucial factor behind longevity, as was having more than four children by the age of 30 and working on the land.
'This study provides the first estimates of height, body build and other vital characteristics for the future centenarian,' the Telegraph quoted Leonid and Natalia, as saying.
The couple will reveal the details of their findings to a meeting of the Gerontological Society of America in San Francisco next week.
The study involved analysing the records of 171 men born in 1887 who reached the age of 100.
'Our initial expectation was that thin people would live longer. But it really does not do much, compared with medium body build. There is no need to suffer,' Leonid said.