Im not implying you are fat, or anything. But a couple years ago when I was drinking heavily, still eating dinner while drunk, etc. Got up to 270ish? The odor that the sweat around my neck would put off smelled a bit like used motor oil? Gas? I "think" I had the beginning stages of diabetes, maybe? My doctor said I didnt have any problems, but if I didnt flush the toilet after pissing - it would grow algae, which is like a red flag for diabetes according to my plumber. Theres other reasons, too, like old age and stress. Was just so weird. Ive since then dropped down to 180ish and the smell has disappeared.
