Hi! Check out the Chia Chat
thread for ideas how to use the seeds. [ETA: I saw Karen posted the same link while I was writing...]
I can't remember if they discussed limitations, but I personally think that it would be hard to eat too many, they are so filling. One tablespoon in a glass of liquid lasts me all day. But I guess 1 serving would be the limit (on my bag, 2 Tablespoons is a serving).
I haven't cooked with them yet, just added them to a drink. Which by the way entertains people to no end as it looks like a bunch of fish or tadpole eggs floating in your drink!
I don't know about the dehydration factor. Maybe they mean if you eat them dry, they plump up inside of you and thus would absorb some liquid. But if they are already plumped, it seems like this effect wouldn't exist. Just a guess. I did a quick search and most of the articles I skimmed actually said that the seeds help *prevent* dehydration. I'm not endorsing this site, but this
is what came up first.