I Recently Joined A Physician Driven Weight Loss Program (and

I recently joined a physician driven weight loss program (and have lost 37 pounds since August 31). I had labs drawn on Aug 25 and had a TSH of 3.71. The doctor wanted to start Synthroid but I wanted to wait to see how my 3 month labs turned out. My TSH was higher 3.85 !!! So, she is on me again to get me to take Synthroid. Most lab result scales that I find show that 3.85 is not in the range that a thyroid replacement would be necessary. My question is, why would my TSH get worse with healthy habits instead of better?