It all depends on the dog itself, the breed, the age, etc..
When I got both of mine, they were skin and bones, so I kept food in the bowls at all times. So I never got either of them on an eating schedule. (I know I should!!) But even with food in there bowls all the times, they only go to the bowl and eat twice a day, in the AM when I'm getting ready for work, and in the evening when were winding down watching TV.