Research cited by Robert Cohen has made the point that there is up to a gallon of extra mucus in the body created as a result of drinking dairy. The mucus problem is associated with the fact that 87 percent of milk protein is casein, the main ingredient of Elmer's Glue.
Gabriel Cousens (2007). “There Is a Cure for Diabetes: The Tree of Life 21-Day+ Program”, p.55, North Atlantic Books