How do you know how much to feed a dog? Do you follow the recommendation on the side of the bag/can? For Penny, who weighs 45 lbs., the bag says to feed 3 1/4 cups/day -- I feed her 2 cups/day, which is what they recommend for a 30 lb dog. The vet always tells us she's overweight but she's nearly always weighed between 43 and 45 lbs. I had her on 1 1/2 cups/day for 6 weeks to see if her weight would reduce. She looks the same to me. For Dio we feed him 1 cup/day but the bag says for a 20 lb dog to feed 2 1/2 cups day. It's puppy food (his last bag). Sometimes they are full on what I feed them but the past few days Dio has been hungrier so I've given him 1 1/4 cups. They get fed around 11am and 4pm. They get a mile and half walk nearly everyday plus lots of run/chase around the yard, weather permitting. So how do you know if you are feeding them enough but not too much?