I think part of the issue is also that humans don't actually know what a healthy weight for a dog or a cat even looks like. We get criticized all the time that

I think part of the issue is also that humans don't actually know what a healthy weight for a dog or a cat even looks like. We get criticized all the time that we are underfeeding our dog; that you can "see her ribs", that she's "way too skinny". Yet according to the vet, she's about the right weight — maybe a tiny bit over.