Ive been struggling with this to the point where I needed enemas to evacuate. I went off my low carb diet I had been following for months. NOt only do I feel better but I'm pooping again on a normal basis and the burping is gone way down and I just feel better generally.
So, I think w/o the sugar/carbs in my diet I"m just not producing enough energy in my mitochondria for the colon to have effective motility.
When I go back on the diet, I'll add in carnitine (it brings fats etc into the mitochondria) adn see if that helps the constipation and overall motility.