Can you have an allergic reaction to a food in excess amounts?

Too much food: Only if you are allergic to it in the first place. Some allergies need only the slightest exposure to trigger a reaction, while others take a lot.

Reactions: In general, allergies start as a cascade of events produced by an allergen (molecular level) interacting with an already sensitized organism. Testing for allergies is done with tiny doses of antigens. Intoxication is different, it may occur with large amounts of virtually anything (including water!).But the more allergen, the stronger the reaction, up to certain point. Hope this helps?