"When you restrict calories too severely, the brain's reward system- which includes dopamine and receptors, the same ones involved in drug addiction- becomes more sensitized to anything that might boost reward, says Mary Boggiano, Ph.D., a psychologist at the University of Alabama at Birmingham. For the dieter, that is typically junk food. This supersensitization in the brain may be why dieters crave junk food and why it is hard to not overeat once they have eaten just on bite of a tasty treat."
