I can't believe I'm responding to a thread about constipation!
I'm regular as the sunrise at home, but sometimes when traveling have this problem. My first remedy is usually a large glass of hot water. On the rare event that I am irregular at home, I find that drinking some fresh carrot juice from my juicer has a salutary effect...
Also, as I've gotten older, I've also developed an occasional case of acid reflux, so I can't eat ANYTHING for a few hours before I go to bed, and cheese seems to be a particular problem.