Nutri-Cal is great -- if Charlie likes the taste. Kuhio hated it, so it was difficult to get enough in her to help maintain her weight. How old is Charlie?

Has the vet done bloodwork on Charlie? Kuhio developed hyperthyroidism when she was 16. Her little body was burning calories faster than she could consume them. And the fast metabolism caused her to throw up a lot.

Please keep us posted.