The sedentary lifestyle that often accompanies FM can cause weight gain. It is important, unless you have another condition that prevents it, to exercise, and stretch. Treat myofascial trigger points, if they are present, prior to exercise, or it can cause a worsening of symptoms leading you to believe FM is a progressive illness, which it is not.
Hypothyroidism is believed to be a comorbid condition in FM, and research is underway on thyroid resistance, where the thyroid hormone levels are normal, but the body doesn't utilize them appropriately. Research also shows a possibility that having Hashimoto's Thyroiditis puts a patient at greater risk for developing FM.
A hallmark symptom of hypothyroidism is weight gain.
Find out more about this book:Integrative Therapies for Fibromyalgia, Chronic Fatigue Syndrome, and Myofascial Pain: The Mind-Body Connection