I wouldnt feed an 8yo senior food, but i do use senior food to help control their weight, both the girls have lost weight since being on senior only (although only one needed to lose weight!!). There are foods on Zooplus for seniors, like Almo Nature, RAfine Soupe, but mine tended to be fussy over them, so they are just on Felix now. Whiskas Oh So does a senior variety and that is higher meat/fish content than normal Whiskas.