Holly Krahe wrote:

 >1) Why do you think that your diet will be the focus of your visit?  Lack of
 >periods in a young healthy female should never PRIMARILY indicate a need to
 >rework diet!

Not necessarily true. Undiagnosed celiac disease can cause these problems.
Here's something from one of the doctors studying celiac disease:

Dr. Joseph Murray, University of Iowa (now at the Mayo Clinic), speaking at
the 1994 American Celiac Society Conference, held on June 10-11, 1994.
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Untreated celiac women often have low estrogen levels and an erratic
or non-existent menstrual cycle. In both men and women fertility can
be affected and rarely is the major manifestation of celiac disease.
For young untreated celiac girls, the onset of menarche can be
delayed. Like so many other symptoms, these problems are caused by
malabsorption. Once the gut heals, these problems are usually
eliminated. Note: Women with a long history of malabsorption will
sometimes reach menopause at a younger age; in some cases as early as
in their late twenty's.