It sounds a bit like Dumping Syndrome to me. Have you had any gastric or gall bladder surgery? Here is a definition by Wikipedia.
Gastric dumping syndrome, or rapid gastric emptying, happens when the lower end of the small intestine fills too quickly with undigested food from the stomach. "Early" dumping begins during or right after a meal. Symptoms of early dumping include nausea, vomiting, bloating, cramping, diarrhea, dizziness and fatigue. "Late" dumping happens 1 to 3 hours after eating. Symptoms of late dumping include weakness, sweating, and dizziness. Many people have both types.
It is speculated that "early" dumping is associated with difficulty digesting fats while "late" dumping is associated with carbohydrates.