I have similar problems, but not as severe. My food its partially digested, except nuts and fruits which are COMPLETELY intact in the toilet, amaranth for example its 30% digested, other grains more but still undigested to some degree. I think carbs its the thing I digest worse looking at the "toilet results". Veggies are partially digested too, if raw they are almost intact, meat its the only thing I havent seen undigested.
Of course, I have IBS and Leaky Gut. The IBS appears mostly at night with bloating, gurgling and gas and a bit at mornings as dull ache (this is because the stomach have been bloated and gassy all the night while you sleep). I have tests proving I am intolerant to most of foods (scary) and that my whole body but especially my intestines are inflammed.
I suspect I have severe underactive pancreas and digestive system for some reason, probably heavy metal toxicity. I am trying GB3 and water kefir drank and in enemas soon. Will tell you how it goes.
This maldigestion and malabsorption combined with my stupid no carb diet for months in the past its making me lose pounds so speedy I currently look anorexic and I have been forced to increase drastically my carb and calorie intake as an emergency measure. But I know im doing everything in my hands and eventually will win this battle.