We see a man in a mobility scooter regularly on our walks and stop to chat to him. He has a 9 year old CKCS with a heart problem and it is very chubby to put it kindly!
I didn't mention it to him though as it is obvious he thinks the world of his dog. One time when I was on the park with him talking Parker found a large victoria sponge cake someone had thrown away and was frantically wolfing it down as fast as he could before I got hold of him! The CKCS owner said smugly "My dog doesn't scavenge" so I replied cheekily "That's because he doesn't need to-he is fat!"