Most veterinary prescription diets formulated for cats with bladder stones contain lower levels of magnesium and phosphorus than does regular cat food. These lowered mineral levels increase the acid content of your cat’s urine in an effort to dissolve the struvites. Additionally, the food is higher in caloric density to help your cat eat less, thus lessening the amount of minerals excreted in feces. Higher sodium levels increase your pet’s urination in an effort to rid the urinary tract of crystals and the bacteria causing the UTI.