How to monitor your cat's weight
1. Feel their ribs
They should feel kind of like pencils under a blanket.
2. Check their waist.
From above, you should see an indent behind the ribs.
From the side there should be a slight upward tuck of the belly.
3. Touch their belly
If their belly sags, touch it to see how firm it is, if it is just a flap (often you can see it when they walk) this is normal. If it's sagging and quite firm you may need to adjust their portions.