For a given person body weight is largely dependent on diet, exercise, and metabolism. If you have a good thyroid doctor that will treat your symptoms by testing and adjusting levels of the actual, biologically active thyroid hormones (free T3 and free T4), then you should be able to get your metabolism back to what is normal for you. FT3 is the most important because it is four times as active as FT4, plus FT3 largely regulates metabolism and many other body functions. Studies have also shown that FT3 correlates best with hypo symptoms.
So the first thing I suggest is to get tested for FT3 and FT4 along with TSH. Since you have apparently already been diagnosed as hypo, you should also get tested for the autoimmune antibodies, TPO ab and TG ab. Be aware that many doctors resist testing for FT3, and sometimes FT4 as well. Don't accept that. You're the customer, insist on it.
When test results are available, I suggest that you get a copy and post here so that members can help interpret and advise further. Also, be aware that FT3 and FT4 results just within the low end of the range are frequently inadequate to relieve symptoms. Many members report that symptom relief for them required that FT3 was adjusted into the upper part of its range and FT4 adjusted to at least midpoint.
hypothyroidism, with its penchant for slowing down everything else in our systems right down to our cells, slows down our body's ability to process carbohydrates and our cell's ability to absorb blood sugar.
here is a very good article that explains how our pancreas, liver, stress, metabolism and thyroid etc.. work for us and against us when dealing with hypothyroidism and the host of dietary difficulties it can create.
http://thyroid.about.com/cs/dietweightloss/a/losingweight_2.htm
I hope you find this information of value.. Wishing you the best of health.
~ Donna ~