Does remission mean the intestine can absorb nutrients normally and the fatigue and pain is completely gone?
For me if I follow a strict diet and exercise moderately, there are 2 to 3 days in a week when I feel mostly fine, but it would contradict the test results. I guess when the inflammation is silent, feelings can't be relied upon.
Correct. If you feel okay but the inflammation and ulcers are still there, that's not "remission" in the medical sense. I'd call that "having a good day" despite the presence of active disease.