"The sodium and carbonation in sodas help you retain weight"
carbonation? since when?
I have actually never heard of that, and don't believe it does anything either way (the carbonation itself) due to the nature of carbonation it, by itself when trapped in your system will not make you weigh more, in fact if holding a gas in our system made us weigh noticably more, holding our breath when on the scale would make a difference
as far as deinking water goes, yes I feel like it has made a difference in my appetite, as whenever i feel hungry, i have a glass of water then let myself eat, i notice i tend to get fuller faster than before, most likely because the water is filling space in my tummy that could normally be filled with food :P then again it could be just a placebo effect, either way, water is good for us (to a certain extent obviously) and it's good to get our water in
oh, and one thing i do know for a fact is that dehydration slows our metabolisms (among other things).
One thing that i think is important is that not all waters are equal.... I try to get in as much mineral/spring/artesian well/glacier water (artesian well is my fave, and best tasting for me) as i can because they actually have minerals/nutrients in them, oh and tap water is better for you than you'd think, as a rule, as long as it tastes ok in your area it's good to drink because it too will have minerals and stuff. I figure i should give my body as much help as i can now, seeing as i was treating it like crap before