I have an older cat about 16yrs old, she eats and keeps food down most of the time, but does through up at least once per day and it is undigested food, our vet says she seems fine as far as weight and her health is normal and can see no obstuctions in her throat. She eats dry cat food and once daily gets about a table spoon of canned cat food, this she never keeps down. What is going on and what can I do to help her