In our experience each individual has different energy needs and two dogs can have very different food requirements and weight fluctuations. Pet obesity is becoming a huge problem just as in people. Also BE ADVISED, I’ve seen many veterinarians think that a fat/chubby dog is the perfect weight. No disrespect to your vet, please do your own science based research before going with their word as the Bible. Goldens are prone to joint issues, and obesity can directly and exacerbate affect this health issue.
Here are a couple good visual references for you (click on each to enlarge):
The Association for Pet Obesity Prevention has some great resources you can check out.