In 2016 The Kennel Club  launched an information guide on managing your dog's weight. Apparently it is estimated that about 45% of dogs are overweight and it is hoped this new guide can help owners of dogs that need to lose weight. The guide discusses how to tell if your dog is overweight, examines the cause of obesity and provides hints and tips to owners. If you are concerned about your dog's weight please consult your vet.

As a rule of thumb you should just be able to feel the ribs of your pet. He should also have a waist but not be so thin that the pin bones are very obvious.

https://www.thekennelclub.org.uk