I am experencing the same problem as you are. Please save your time and money from those doctors. I have done upper and lower IG,seen different doctors and they keep telling me there's nothing wrong with me, but I know there's a curse for these fecal Body Odor .
I tried chinise bitters (www.sensiblehealth.com/halitosis.html)and I my Body Odor has reduce. Best thing is I don't give out gas anymore, but am still experencing bad breath. I know it a little better now.