Your friend wants to break the habit of overeating. What suggestions might you give her?

What will be an ideal response?

a . Habits are often entrained to stimulus cues that support their continuation. They will require self-control to overcome.
b. Self-control is a resource that can be depleted, so first she should not try to quit at a time when she is under stresses that would reduce her self-control. Find a time of year when she is most relaxed to try to break the habit.
c. In terms of the circumstances, I would encourage her to try to identify the situational cues that trigger her eating and change those. Many people find it easier to break a habit if they change the situation or social group they are with that triggers the habit. If she has a group of friends that encourage her overeating, I would suggest she find a time to interact with them outside of meal/snack events.
d. Sometimes it is even literally helpful to change locations. As contrary as it may sound, vacation may be just the time to try to change one's eating habits, because the situations are all new and the stimulus cues that normally triggered overeating would not be present for her.