my cat has 1 pouch of meat a day and her biscuits, I use Iams so she gets all her nutrition from that, it is recommended if feeding from tins 1/2 a tin a day, my cat isn't overweight, her fur is always silky and shiny (sign of a healthy cat) and has been on this diet for the last 20 years (she's an old bugger) She still has all her teeth and has never had any health problems. Perhaps yours isn't getting her nutrition from go-cat, Iams is a little more expensive, but you use less of it as it gives them everything they need, unlike go-cat which is just a cheap sub-brand. Try swapping for a few weeks, and if it helps, keep going with it!