I wait at least an hour with my Doberman, preferably 2. They are deep chested dogs and very prone to bloat. If my dog is going to do hard running, I wait 2 hours after he eats to run. (I'm not talking a little mild romping) And I don't exercise him right before a meal either...not within 1 hour before eating. It's a terribly dangerous thing and any dog can suffer it, but the larger breeds and especially deep chested ones are really prone to it.