There's always a lot of controversy over how to feed dogs... many people prefer a raw meaty bone diet and nothing else. My own dogs get a commercial dry food in the morning, and a raw kangaroo tail in the evening, and they're thriving. My last Australian Cattle Dog lived til 12, she didn't have a day's illness in her life until she got a brain tumour, and she won in agility an awful lot. So, if your dog eats Royal Canin, go for it. The big issue with commercial dog food is that it isnt' really good for dental health, and bad teeth mean bad hearts, etc so if you toss in a few raw bones and keep an eye on the teeth I'd figure you'd be fine.

Cheers

Scotia