Bane, have you had this "fainting" business checked out? Too low blood pressure? Orthostatic hypotension? Potassium levels? Are you considerably underweight? Are you anemic?
And, by the way, when I eat my main meal of the day, my body is so busy digesting the food it doesn't have the energy to maintain my body heat and I get CHILLS, I don't care how hot it is inside or outside, I get CHILLED. And it takes a long time and drastic measures to get warmed up again: usually fleece shirts, sleeping bag, bed blankets and comforter and "sleep it off".