Originally Posted by
Celista
If the dog is not lactose intolerant there is no reason to avoid giving a dog dairy, also different dairy products have various amounts of lactose in them. Problems really only exist when dogs are given the wrong types of people food (grapes, chocolate, etc), or are given too much people food, which can create vitamin deficiencies if it's the wrong type of food that is given consistently. Or cause weight gain. Remember that dogs became domesticated because they were scavengers who befriended humans who gave them their HUMAN FOOD scraps. Their food tolerances have evolved to reflect this.
Low-quality dog food is basically corn. "Human food" is oftentimes superior to many dog food brands and there is no need to avoid giving dogs human food entirely, but as the average person does not know how to meet a dog's vitamin and mineral needs (unless they are super dedicated and do an extensive amount of research) and most quality dog foods are balanced around this nutrition, human food is better left as an occasional treat.