Best Answer: Mukund. They don't: a dead body weighs the same as its normal weight. It seems heavier because if the person is alive, they can balance and help be more convenient to carry. Rather I feel it should be light due to gravewax. Grave wax, or adipocere, is a crumbly white, waxy substance that accumulates on those parts of the body that contain fat - the cheeks, breasts, abdomen and buttocks.