Help! I need to figure out what type of weight control food to feed my dog, he is an Alaskan Husky. He is starting to gain weight and I want to make sure we stop it now before it gets too late. Specifically I am looking for good brands I can buy at Petsmart. For one of my dogs, it's too late...he's obese

. The doctor said he needed to loose 20lbs and has put him on prescription food R/D. Is that brand truly good? My dog other dog wants to eat it, but it's too expensive to be feeding that to him (he's not obese). Any suggestions would be greatly appreciated

, thank you.