Live fast and die young, thats what i always say rosie pronounces as she stuffs down three more ding dong snack cakes and opens another pint of high-fat icecrea,. rosie knowns that her diet is unhealthy and harmful, of course. to reduce her dissonance, rosie it

I believe the answer is: adding a cognition that is consonant with her problem behavior

In social psychology, disonance refers to a situation when a certain individual is experiencing conflicting beliefs/principles.
 adding a cognition that is consonant with her problem  tend to provide the individual with a certain level of justification that they can use to defend the false action that they do knowingly.