LO is six months old and we are just venturing into solids with a combination of purées and blw. He has been exclusively on breastmilk up until now. I've read that solids can cause constipation and I'm wondering if I should be proactive in feeding certain things to help keep him regular or avoid anything that is likely to stop him up.
I've read that apples and banana can both cause constipation but I've never heard what does the opposite. I'm hoping to balance it all out since I want to offer variety of flavored and textures anyway.

Any suggestions?