Our largest dog is extremely active. He is a great bird and rabbit dog and he runs and runs and runs when we're not hunting. He'll follow the tractor for miles back and forth in the field. He's skinny but, according to the vet, exactly where he should be in weight.
Our neighbor's mom called the animal warden on us for not feeding him. He eats better than I do.
Her dog is a morbidly obese miniature collie.
Most people's perspective of ideal animal shapes is incorrect.