Some people remember there past lives in great detail thats accurate.
While popular several decades ago, hardly anybody uses this angle any more because it is so dubious. Also, there are possible material explanations for this man's change in weight, which have not been eliminated. Just because we know there cannot be a heaven or a hell, this does not leave reincarnation as the unavoidable alternative. Yes, but the matter and energy which make up an organism's consciousness is converted upon death. The structures and energy which allow consciousness are converted to structures and energy which do not allow consciousness.