I feel your pain. I have been dealing with the same problem for the past 2 years. It's weird because I actually have noticed the odor in the past but it only came on at certain times. For instance, when I would be on a trip somewhere I would notice that my car would smell afterwards like rotting food. Sometimes if I sat in front of the computer for too long I would also notice an odor from my anus afterwards. I just can't come up with an explanation. 2 years ago I started to smell everyday so since then I have been trying different things. I have tried enemas, salt water flushes, probiotics etc.
Yesterday however I got lucky and scored some glycolax so I look forward to trying it even though I have already tried laxatives. Maybe this one is different. Sometimes the smell is hardly noticable and sometimes it is really strong. I have literally had to fight to stop myself from going into depression. I don't know how I have managed to do it but I think I have done a pretty good job so far considering the situation. All this and I was dealing with my mother dying of cancer just over a year ago. So I figure if I can make this far, then I am not going to give up until I figure out what is wrong with me and how to fix it. Of course the doctor acted as if I had some kind of mental problem when I told him about the odor. He said "I don't smell you" and "if I walk out of the room and walk back in will I smell you?"
I tried to explain that it's not that simple. Sometimes I don't even smell it myself until later in the day and other times I wake up smelling myself in the morning. I know it's not just me because I have heard comments from others about something smelling like "old food."
So yeah, I can relate to your problem. I'll let you know if the glycolax helps at all...