Final answer:
The woman's symptoms are most likely caused by hypothyroidism.
Step-by-step explanation:
The condition that is most likely contributing to the woman's symptoms is hypothyroidism. Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone. Common symptoms include weakness, fatigue, constipation, and muscle weakness or pain. The woman's long history of eating disorder, lethargy, constipation, and abdominal distension are consistent with the symptoms of hypothyroidism.