The biggest problem with weight control in dogs is that people have a hard time feeding smaller quantities of food to their dogs. I am the same way. So I cheat on her diet. One way to compensate for this is to add string beans or carrots to the dog food. They add bulk without many calories and most dogs tolerate them pretty well.
Some dogs even grow to look on carrots as a treat.
I wish I did have an easy solution to this problem. One dog is a mixed breed and is 11 yrs old he is just starting to show signs of stiffness, and the other is a German Shepherd about 90 lbs. Thank you for your help. I am still in the skeptical mode when it comes to glucosamine and chondroitin but enough of my clients feel that their pet improves on these medications that I am giving them the benefit of the doubt and do often recommend trying them to see if they work. I think it is reasonable to try them and see if they help.