Well i donot have dogs, but i do have overweight kitties, and to be honest i have one success story, my lexie has lost over 2pounds, and i did not buy any special diet food as such, i just limited her intake to what the packet said for her to loose weight, and was strict about it and it worked, so maybe that is all you will have to do,but you do have to be super strict. ,but of course if that is not working as you say, then combination of low cal food and intake should do it, good luck.