A fluid-restriction diet limits your daily intake of liquids, as well as foods that contain a high volume of fluid. The purpose of a fluid-restriction diet is to prevent the buildup of fluid in your body, a condition that's called edema.Your doctor may prescribe a fluid-restriction diet if you have end-stage renal disease or are on dialysis. A fluid-restriction diet is also part of the treatment plan for congestive heart failure. fluid-restriction diet limits your daily intake of liquids, as well as foods that contain a high volume of fluid. The purpose of a fluid-restriction diet is to prevent the buildup of fluid in your body, a condition that's called edema.