Just to add a thought to the thyroid issue. When I was freaking out about possibly having Graves', I ran across a bunch of discussions on a thyroid message board about hypothyroid people whose TSH levels were normal but who were having problems with weight gain. If I remember correctly, their bodies were having a hard time converting T4 to T3 (or maybe it was the reverse). Adding a different drug, whose name I can't remember, helped in most cases with the conversion. I'm sorry this is rather vague, but I wanted to throw it out there as something to look for in your numbers. The sense I got from some of the discussions is that many hypos find it frustrating if they're working with docs who are only looking at their TSH levels. I'm not sure what tests your doc runs....

To be honest, your diet and exercise look really sound. You shouldn't have to ride 500 miles a month to maintain or lose weight. In fact, with that type of activity, it almost becomes hard to lose because that level of exercise really stimulates the appetite and takes a fair amount of food to sustain.