I certainly agree with Spencer. My 18 year old male is very thin and he prefers eating small quantities of food several times a day. This apparently helps him to keep food down. One of my female cats is short and quite chubby and adores eating; obviously she tries to take advantage of it.

My male cat also has some age-related health problems and needs to take some medicines (mainly homeopathic remedies) to help him along and stimulate his appetite. The vet suggested to put it in his food. This makes things rather difficult, he eats only when he feels like it and therefore it's not easy for me to track who eats what and the last thing I want it to stimulate the appetite of the wrong cat!