You can experience a slew of mood swings and side effects if you have a food intolerance to lactose, the sugar primarily found in dairy products. While a food allergy may cause you to break out in hives or make it difficult to breathe, a milder form of an allergy may result in unexplainable mood swings, according to Food for the Brain, an informational site provided by the Brain Bio Centre. Gluten, used in a number of ice cream formulas, also can lead to the blues, headaches that make you cranky and aggressive behavior.