I feed the boys around 1 lb per day each... usually divided between two meals. If I'm feeding something like a split chicken, or turkey carcass, or a split rabbit, something BIG and whole like that, they get one meal. Actually, even on one-meal days, I usually feel bad and give them an organ meal or tripe or cottage cheese or something at night. ; )
As far as activity, I'm not sure if that can be a rule of thumb for all dogs. Both of my boys are equally active. They go to the park together every day, they get walked a couple miles every day, and they play with each other every day. Gonzo weighs 10 lbs less than Fozzie. But, Gonzo is usually fed about 1/2 lb more than Fozzie... and Gonzo is extremely lean, while Fozzie is, erm, festively plump. It's just their body types and their metabolisms. I would not feel comfortable feeding Fozzie much less than he already eats, and I do think he's at a healthy weight, he's just stocky. I like raw because it's SO easy to just eyeball the food, and adjust it accordingly, and it's SO easy to cut out or add in calories.