It's a myth that you can't mix raw and kibble
It has nothing to do with being a myth. It has to do with poor culinary practice. The Americ V Assoc has already scientfiticallly proven that cross indulgers carry 300-500 times more bacteria in their mouth and digestive tract than those who eat plain kibble, or plain raw food.... because like what happens in the dog bowl, bacteria grows in heat and moisture, just like in your dog's mouth. It's no different. There is still loads of mis information out there about the Raw Regime, and many different takes on the subject. I still meet people who run around bragging that their dog's poop is now nice and white and easy to pick up. Little do they realize that white , light brown or crumbly poop means not enough nutrition!
I think if you canvas the learned "raw" community at large and mention the name Pitcarin you need to be ready to run out of the room. He's been debuked even by other raw vets now for years and years. His information is passe - and there are many other better resources available to learn about the diet.
The fact that both foods may come out of your dog at the same time, doesn't mean the kibbled offered any quality bio-availablility to the dog. It didn't - because it wasn't able to remain in the digestive tract long enough . It was simply pushed out. So while there may be no direct danger mixing the two , you are robbing your own dog of nutrition. You may as well donate your kibble to some needy source. And I'm not at all trying to be cynical.
The objectivity of the "RAW" movement is to put your dog on a species appropriate, natural
diet. That's the focus of the diet...
Eating commercially prepared raw meat is no different than giving your dog meat out of a can. It's processed food. It may be raw, but it's processed. Raw food is a simple ideal of raw meat WITHOUT additives or tampering, and commercial raw does not fall into that category at all.
To the person feeding oatmeal:
If your dog is healthy, then why not just feed it normally so that weight gain is a natural process? If a dog isn't gaining weight, then you have to look towards a possible medical problem. Forcing weight onto a dog is never a good idea because it is possible that the internal organ system can't handle that extra weight.