Whatever the reason this is stated, I think this phrase should be explored a bit. Let's go over some things regarding this often heard statement ...
First, "human food" is subjective. I mean what exactly does this constitute? Food only "humans" eat like orange juice, Tootsie Rolls, Doritos, Fruit Loops or Thanksgiving turkey? I mean we wouldn't feed those things to our dogs, right? But, really, what is "human food"?! If we want to get into semantics all living animals (including humans) eat the same food, with a variation of some or all of the following: meat, plants, grains, veggies and fruits. All living creatures eat some or all of those types of foods. Dog food, while highly processed, has some type of protein in it and plant and/or grains/carbohydrates of some kind, usually rice or sweet potatoes -- which are "human foods", right?!
However, I get it. When people proudly state this to others they aren't really thinking of it in the way that I am. I understand that they are often saying when they are eating their meal they don't feed it to their dog off of their plate. I mean, usually, this is what they mean. By not feeding a dog off of their plate they often feel like this will eliminate things such as: begging behaviors, food snatching and obesity. I understand the desire to have a dog not beg or grab food or get overweight -- definitely goals most dog owners would love to achieve!
how to solve counter-surfing here. Some dogs steal right out of trash cans or even worse -- right out of people's hands! I see the last behavior commonly with small kids because they are easy targets. These behaviors can be solved with training but again, "human food" isn't the issue here.
Raw & Natural Nutrition for Dogs" by Lew Olson if you'd like to learn more about canine diets.
Now, in relation to training ... "human food" can be highly valuable. Depending on what you're working on and where, high-value foods such as boiled chicken, freeze-dried liver, cheese and hot dogs can be a big help in a training program. I always recommend some type of "human food" for recall training and training in distractions. Dogs aren't going to come to you off-leash in a park if you are offering Kibbles 'n Bits. Yuck. Fido would rather chase squirrels. However, give your dog a big incentive like coming to tidbits of chicken and you'll strengthen your dog's recall really quickly!
Sunshine Dog Training & Behavior, LLC
Dallas/Ft Worth, Texas