RESUMO
Since the original description of the obesity-survival paradox in 1999, which suggested a survival advantage for overweight and obese patients undergoing hemodialysis, a large body of evidence supporting the paradox has accumulated. The reason for the paradox has yet to be defined. Better nutrition may be a partial explanation, or it may be that in uremic milieu, excessive fat and surplus calories might confer some survival advantage. The "surplus calorie theory" as a potential mechanism for the paradox is of great interest. If proven to be correct, it might explain why peritoneal dialysis patients who receive excessive calories through dialysis do not exhibit the paradox and, secondly and more importantly, therapy could be directed to enhance a greater caloric intake by renal failure patients to engender a better survival outcome. Finally, other clinical settings, for example, congestive heart failure, have their own obesity-survival paradox. Thus, the paradox appears to be a wider phenomenon and might merely be the external expression of a larger principle yet to be uncovered.
