My dogs diet

Question
I have a mixed dog.  I believe he is an English Foxhound/German Shepherd mix.  He is about 3 1/2 years old and last he was weighed he was 80 some pounds.  He has bad hips and I know he is over weight.  I can't run him or exercise him much because his hips hurt so bad he can't go very far.  I was wondering what and how much I should feed him for a diet so that he can lose weight and also if you have any suggestions on how to make him more comfortable with his hips.  
I'm currently giving him Indoor Dog Food by Pedigree I believe.

Thank you!

Answer
If he needs to lose weight, then he needs to be on a vet supervised weight loss diet like OM or R/d. Using store brand dog foods at reduced amounts does not really help safely take weight off.

There are new drugs like Adequan, to rebuild the cartilage, and the non-steroidal drugs like Previcox and Rimadyl that will  help to relieve the pain.