Why does my sweat suddenly smell sweet like baking bread?

About 6-8 weeks ago I noticed my sweat starting to smell sickly sweet, like bread dough. It got stronger and stronger, so that others noticed it too. Not localized to any part of my body, just an all over smell. I moved to central Texas in Aug. 2010. Two weeks ago I went home to the east coast for 10 days and the smell went away. Now that I'm back in Texas, on the second full day here I'm noticing the smell again. Doctor is stumped. What's going on? Could it be something in the water? Why wouldn't the change have occurred last August? (Note: I'm also working on getting my hypothyroidism under control, if that seems relevant.)