When you say 'can't eat', do you mean you get sick and throw up or you get gas/indigestion, diahrea or what? Since I've been in my forties my monthly has been off and on. I do notice my tolerance for certain foods has diminished. Particularly spicy foods, certain sauces, dressings, most anything greasy, including stuff like dark-meat poultry. Can't have yogurt either. However my reactions are usually constipation, indigestion, gas (out the mouth and out the butt) and chest pain. Rarely diarrhea and rarely vomiting.

I keep a log now of everything I eat and have come up with a 'bad food list' which is a list of every food that 'bother's me. I also have come up with a 'good food list'. Which contains foods that I like that don't bother me regardless of whether they are considered healthy or not.