Finger Food Causing Major Discomfort

Idahomama

So DS has decided he is no longer interested in eating pureed foods.  So we have starting trying to give him finger foods.  He loves the idea of feeding himself and does quite well at it.
He has always suffered with being a pretty constipated kiddo.  It doesn't help that he is has to take the thicker AR formula for spit up.  Anyway, I have avoided bananas and cheese because I know they cause constipation. 
He seems to not only be suffering with constipation but is really gassy too.  We started those little meat sticks (cutting them up into small pieces) and he liked them.  We also tried kidney beans and he really like them as well.  Those were the only "new" finger foods we tried this weekend and he had a really rough couple of nights.
Any ideas if your kiddo suffers from the same thing?  Foods to try or foods to stay away from?
Thanks ladies!

in my life

C has been constipated off and on since starting solids. When she is, I give her a sippy of half prune or pear juice and half water, but I don't avoid any particular foods. It usually does the trick!

Idahomama

I should add we give him prunes every morning. Sensistive tummy because it still doesn't always work.