The more pets become a part of the family, the less they live outside and rather indoors with us. Freedom, my black lab, gets spoiled like my own child complete with a comfy dog bed with matching pillows.
Although we walk at least 30 - 60 minutes an evening, because of his age and natural inactivity indoors, I really need to be careful in regards to his weight and calorie consumption.
Dogs in general eat the same amount as outdoor farm dogs. Add that with all the treats we give them on occasion can lead to some heavy calorie storage.
We don't think about calories for our pets the way that we do for ourselves.
It's obvious that unhealthy eating and obesity can lead to physical illnesses, however, obesity can also lead to canine and feline depression.
Allowing your cat and or dog to play outside for at least an hour or two supplies natural vitamins contained in sunlight for their coat/fur such as Vitamin D which is often missed in commercial pet foods.
The difference between a cats & dogs metabolism is associated with grooming. There is a higher percentage of obese cats than there are dogs simply because when a cat grooms him/herself, the hair balls sometimes gets swallowed thus causing food digestion to take up to 4 hours, whereas a dog is ready to expel the waste within 30 minutes.