The weight issues associated with thyroid disease are not fully understood at this stage.
The usual response is in line with the changes in metabolic rate so Hyperthyroid individuals usually lose weight while Hypothyroid individuals usually gain weight and this is primarily related to FT3 & FT4 levels, but there are a number of other hormones including Leptin, Insulin & TSH itself also play a role in body mass management.
There are TSH receptors (TSHR) present in fat (adipose) tissue as well as other body tissues outside of the thyroid, my reading of this information is that stimulation of TSHR results in Lipolysis so theoretically higher levels of TSH should result in weight loss and lower levels to weight gain. This is the opposite to what is normally seen and may well be explained by excessive TSHR stimulation by the TSHRab's (antibodies) in the adipose tissue of Graves patients, hence causing weight loss even while TSH levels are extremely low.
Many GD patients experience Hypo symptoms and can cycle quite a few times before the go into full blown GD.
So the issue is not that simple, weight gain/loss is just a symptom of the autoimmune disease that does need to be treated, so please do not defer treatment in the hope of losing weight.
The review of studies below goes into TSHR functions in the body not just weight gain, this information reinforces the fact that TSH plays many roles in the body, not just management of Thyroid hormone levels.http://joe.endocrinology-journals.org/content/204/1/13.full
I am not a Registered Medical Professional nor am I a Formal Researcher of any description, therefore everything that I say and write is purely my own opinion that is based on my own personal experience and information that I have read, henceforth anything I say or write cannot be construed as advice in any shape or form.
Every individual needs to do their own research so that they can make fully informed decisions about their own future and take full responsibility for the decisions they make.
My partner is the GD patient, I am just her researcher and advocate.
PTU treatment for Graves 7+ years ongoing, Supported by Low Allergenic Paleo Diet, Supplements, Yoga, Meditation, Exercise and Lifestyle changes.
Tests in Jan, March, June, Sept and Dec 2012, normal range for FT3, FT4 and TSH and receptor antibodies only marginally above normal in March, well in range in Dec - Scaling down PTU dose and looking forward to a remission attempt in the near future.