Dear friend,
Whenever a cat his age consistantly loses weight, I suspect a hormone imbalance or organ disfunction.
Hyperthyroid can cause this, so can inneffient kidney or liver function.You already tested for diabetes so we can rule that out.
If he has Thyroid disfuntion he can eat and eat and still lose weight.Many cats will test in the normal range on the high end and actually have hyperthyroid.
Reduced kidney function will also cause excessive thirst and urination because the cat feels dehydrated.He will keep drinking in an effort to replace lost fluids but the ineffective kidneys will not be filtering them into his bloodstream.
If his liver is not 100% you can also see weight loss because certain toxins are not being filtered out.
If his body is healthy and his bloodwork supports proper organ function then we can look at his diet. At any time, a cat can become intolerant of ingredients in his food, especially if the foods contain grains.
At this point, you will have to do bloodwork to ascertain if everything is functioning properly and isolate a specific cause for he weight loss and get it under control.If it continues he can become sick and debilitated.
I would start by changing his food to a natural one with no grains like felidae, wellness or neutro. I can also give you some links to home cooked food if you would like to try that.
Please let me know what was found and how your cat is doing.
If you have any more questions, please do not hesitate to ask. I will be more than happy to help in any way possible.
Very sincerely,
Terri
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri