It depends on the person and their level of sensitivity, and the food.
For me, it depends on the food and even how it is prepared.
I can have dairy- especially yogurt and cheese, and I can use a little half and half in my coffee, but if I have straight milk or ice cream for example, I am guaranteed to have asthma and eczema the next day.
My son cannot tolerate even the smallest, tiniest amount of Red Dye #40 or nitrates. He turns into a beast in 12 hours. Really. His behavior is awful.