The fattest man in history was John Brown, who was born in the USA in 1941. In 1979, his weight reached a record 635 kilograms. Brown suffered from morbid obesity caused by genetic and psychological reasons. He spent most of his life in bed and required constant care. In 1983, Brown died of complications related to obesity. Today, the fattest man in the world is John Burgess, whose height is 1.98 meters, and weight is more than 450 kilograms.