Drinking fluids and constipation ?

Griffin has been dealing with recurrent bouts of constipation lately. He does not drink enough fluids, he doesn't drink on his own unless I tell him to, even though I constantly have cups of water and diluted juice around. When he comes home from daycare, his cups are still completely full. We've tried all kinds of cups to try and find one he loves and will want to drink out of, and sometimes that works for a day or two. He just doesn't seem to know when he's thirsty, and even when I ask him to drink he sometimes won't. I can't FORCE him to drink. I'm sure part of the constipation issue is that he doesn't drink enough. Anyone have suggestions about how to deal with either problem? I've gotten desperate enough to consider giving him straight juice or sugary drinks just to get him to drink SOMETHING. I don't even know if that would work though, and I don't want him to stop drinking water entirely because he knows there is something better.

Natalie loves to drink everything from water to juice to milk (both chocolate and white), both my girls did at that age. So I am not talking from experience. Maybe you can try giving him some watered down pure fruit juice, or try making the drinks fun, I saw some neat ideas on pinterest for ice cubes, some were frozen kool aid (http://www.mrshappyhomemaker.com/201...ic-potion.html), others frozen fruit concentrates (http://scjohnson.com/en/family/famil...Ice-Cubes.aspx). It might be worth a try.

Oh, he loves ice. That is a great idea, actually.

popsicles!

Some raw vegan friends of mine have pointed out that, when you eat a lot of raw fruit, you don't need to drink as much because you get a lot of water from your food. Would Griffin be up to eating more fruit and less starch (he'd get more fiber that way too)?