Lots of people do demonstrate inconsistency in behavior such as this one; especially on Facebook. Why is she in particular important to you?
If she is lying and in fact trying to get attention, then it means she is feeling neglected in other aspects of her live and that is sad. Of course, she should not be manipulating others’ emotions like that but if she feels hurt and neglected, she is not going to see outside of herself.
On the other hand, she may not be lying. May be she has no idea about the coffee connection and heart health.