A recent study showed that dogs need to be feed twice a day. Unfortunately I don't have access to the study but recently read it. It was from a reliable source. The study looked at the cognitive ability of dogs who were fed only once a day, and found the dogs feed twice a day did better. It's the same idea and process that studies have shown with children. Children who skip breakfast (or later meals) don't do as well with cognitive tests as children who get regular meals. Dogs fare the same. :)
I show dogs in dog agility, and I always make sure my boys get fed twice a day. This helps them maintain both the physical energy and the brain energy to take on the difficult tasks I ask of them. I always felt they show a definite decreased ability if I have them skip a meal. The study proved I was right.
Don't feed only once. Feed twice. :)