ZoE was a VERY fast eater as a puppy. I tried putting a golf ball in her bowl along with the kibble so she had to move it around to get her kibble and it did slow her down for day or two. Then she discovered that if she could just flip the ball out of the bowl with her nose, she could get to all her food quickly again.
She's now 10 months old and now crunches her kibble at breakfast, but still gobbles her dinner. No clue as to why, cos she gets plenty of lil snacks of apple & carrot throughout the day, so I know she's not starving at any point.