Hello, thanks for your question today! I am Dr. Drew, and I am a licensed veterinarian. I'll be happy to help you in any way I can.
Typically, if a diabetic patient is not returning to a healthy weight,
it is a sign that their diabetic regulation is not adequate.
In other words, diet is not the way to fix an underweight diabetic, generally speaking,
instead, the dose of insulin may need to be increased,
or if the dose has been repeatedly adjusted with no success,
causes for Insulin Resistance need to be checked for,
including Cushing's syndrome, infections in the body, or other processes such as cancer.
i know what is wrong with our dog, you have not given a answer to my question?
Actually I did give an answer,
"In other words, diet is not the way to fix an underweight diabetic"
But thank you for giving me a Bad rating, I'm so glad I tried to help you.
have a great day!