It's probably the grease, or at least the quality of grease (some fast food places only change their oil once a week), or it could be an early sign that you're intolerant to low quality foods, which tend to include fast food, diner food, and processed/packaged foods. read more
I have thrown up from funnel cakes, french fries, and bacon. I even landed in the hospital from eating sweet and sour chicken. I get indigestion a lot, mostly with burps that have vomitlike liquid. read more