Not sure how it can be a food intolerance thing since I eat different things at each meal. That would mean I am intolerant to nearly every food. For me, I think it's worse after meals because I have a hiatal hernia and I think there's already so little room in my stomach from the hernia pushing up into it and then I add food and that only make the problem 10 times worse. Then the already stressed stomach puts more pressure on the vagus nerve which is the thing overreacting and causing the heart palps, racing heart, nausea, etc.