B.R.
Hi E M! I've never tried the Similac Go and Grow but I've been using the Similac Alimentum (because my son has multiple food allergies). If the formula you are using seems to cause more gas in your baby, I would switch back. I think it's okay to give your baby formula that's meant for younger babies as long as you're supplementing w/solid foods to balance it all out. Because my son has SO many food allergies, he's very limited in what he can eat (solids) so I still give him the Alimentum (for birth to 12 months) as a supplement even though he's now over 2 yrs old and he's doing just fine. The way I look at it, it's like some adults having to drink Ensure when they're not getting enough otherwise. Does that make sense? I hope that helps. Take care, B.