I am far from knowledgeable regarding diet and nutrition but I recently switched from drinking a good amount of fruit juice and an occasional soda to drinking 100% water. I wasn't really even overweight but I shed 10 lbs within a month and I feel in much better health. I don't think it's just sodas - pretty much any drink with a lot of calories and sugar seem like a waste. Now when I see those giant sized sodas in restaurants I can't believe I used to drink them.