the thing is, for a GSD to have their full ration in one meal, it would be a very big meal, and they're a breed that is susceptible to bloat
the one i mentioned earlier in the thread, i feed, twice a day when i have her, i think her owner tries to do the same, but leaves the food down all day if she doesn't eat it on a morning, for example.
she eats two meals with me, but then my dog is usually around so that could be an incentive to get her food before he gets to it. (he has three small meals a day, he's also on a very low calorie - high bulk diet which in just a few months has him almost down to his ideal body score, he should ideally be on two meals, but he got so used to eating at the same time as our older dog who used to need to eat little and often to avoid her being sick, that the routine has just stuck.)
my friends GSD has a mug and a half of proplan in each meal with a covering if meat, and she's still at the lower end of the amount of food she should have for her size according to the bag, so three mug fulls of food in one sitting for her?
it just doesn;t sound healthy to me. it's too big a risk with some breeds.
their digestive system is generally designed for the to have a binge diet, as wolves do, but the different shapes and sizes of some modern dogs, it just doesn't suit all of them to eat in this manner.