Re: Giving my 6.5 month old water or glucose water.
Formula is constipating. You may need to try some other formulas - my SIL had constipation problems with some of the kinds that she tried. Cereal is contipating too. I would stop the cereal altogether and only give fruits and veggies. P-foods are good for constipation: Pears, Peaches, Plums/Prunes, aPricots, Peas. Cereal is pretty much just empty calories anyway and is totally unnecessary.
If you can express some breastmilk, then that would be ideal (far better than water) because it has laxative properties plus all of the nutrition your baby needs. If not, then a little water might help.
K. Sophia - Mama to my little lactivore, the amazing Mr. X (11/10).