jweeks,

Some laxatives (such as Miralax) pull water into the colon. But you are right that there must be water in the body to pull into the colon. I imagine all of these food ideas to introduce water have been posted on this thread -- JellO, fruit (lots contain huge % of water), veggies (lots contain huge % of water), popsicles.

There are separate threads about constipation. Besides what you've mentioned, you might try Fruit-Eze (fruiteze.com).

Robin