Diet cat food-crystals in urine

Question
hi.. i am trying to help a friend at work.
she has a 23 pound cat who she first tried
putting on a diet when he was 18 pounds but
the vet insists that the cat has to be on a
special diet due to crystals in his urine.
however, she tells me she has been unable
to find any cat food that is both diet/low
calorie cat food that also deals with the
problem of crystals in the urine. i told her
i would try to find out any info.
got any ideas ?
thanks !
you can post this question and your answer
if you would like to.

Answer
Hi Janet!  This is actually a very common question!  For some reason there is no Lite/Diet/Reduced Calorie food for urinary tract health.  At least not in my area.  
If your friend is feeding her cat any canned food, tell her to try eliminating the canned food and feeding only dry, as canned food is so high in fat and calories.  She can also decrease the amount of food being fed in small amounts.  
I have been fortunate, as I "free feed" my cats, which means that they constantly have food out for them and none of my cats are overweight.  Some cats, though, become very overweight when they are "free fed" as they constantly eat, and consume way too many calories.  If your friend "free feeds", she should reduce the feedings to three times a day, morning, when she gets home from work, and before bed. The total of food consumed by a cat should equal 1 and a half cups per day, so she can start there by giving 1/2 a cup of dry food for each serving.  
Activity also helps cats lose weight, just like people.  I have a cat tree, by Drs. Foster and Smith (the catalog).  It goes from the floor to ceiling and has ledges on it for the cat to lay/sit/sleep.  This is excellent exercise for a cat, so she may want to try this.  She can also try purchasing a wand toy that has a feather or some other type of cat toy dangling from it and let her cat chase it.
The combination of these things should have her seeing a difference in her cat's weight and health within a few weeks.
I hope this helps and best of luck!
Hilary