I've experimented around some and found what works best for me is something like a large glass of juiced 'greens' around lunchtime the next morning, followed an hour or so later by either a banana or a salad. Then in the evening a light dinner, usually something like still crisp stir-fried broccoli and snowpeas. Plus, I drink a lot of water during the morning and afternoon to help replace what the Epsom Salts drained away. (I've heard orange juice is a good fast breaker, too, but I can't drink OJ on an empty stomach.)
However, a few flushes back I had a VERY strong craving for really fatty foods the next morning, so I listened and ate high fat for lunch. I felt a little 'gassy' the rest of the day, but did another round of Epsom Salts that evening and passed some good sized calcified stones the next morning.
Unless I get that strong craving again, I'll stick with the juices and lighter foods on the day after. Much easier on my digestive system.