In article ,
Brian or Sharon Beuchaw wrote:

Surprisingly, last night I checked and the Purina ONE Chicken and Rice dry
that we were feeding them has more fat (13 - 16.5%) than the Nutro Kitten
(8% min) and Nutro Adult Science Diet canned (5% min).

That's on an "as fed" basis. The cat's system only cares about the
amount of fat after the water has been whisked away to be used. If I'm
doing the math right, Nutro Adult has about 23% fat on a dry matter
basis. (The Purina ONE dry has about 14.7% for comparison sake). Nutro
Max Kitten has more like 27% fat. This jump in fat might take some
adjustment, especially if the older cat has been eating the same stuff
most of his life.

If the loose stool continues, you probably want to take a sample to the
vet. I'd expect a slightly bulkier, loose but formed stool for a while
from having more water and less fiber in the diet, but not a ploppy one.
That tends to imply that the fat isn't being digested well, and could
even indicate a problem with the pancreatic lipase enzymes.

And of course, as Lauren I think recommended, it's always worth trying
another brand if only to ensure variety and rotate different foods into
the menu.

-Alison in OH