It never really shows your weight, only your BMI unless you click some buttons. As for what is always displayed, it just shows a dot representing the first weighing on a scale at 0 in the y axis. Every time you weight yourself, it will show BMI with an option for lg/kg. On the main screen any future measurements will be shown as a plus/minus from your original weight, but it won't display BMI or lb/kg.
The nice thing for people with disorders, is that BMI says underweight, normal, overweight, and obese. If she is underweight, maybe she will be motivated to get into the bottom of the normal range.








