Just curious. If you were hypothyroid and not on meds, you'd want to be; also the thyroid meds may need tweaking as you go along with the antidepressants, esp. the Cytomel. There is evidence that SSRI + T3 has extra antidepressant efficacy.
If you are concerned about weight gain with antidepressants, probably the better choices are going to be Wellbutrin (or Zoloft among SSRIs), just off the top of my head, but there's no guarantee they will work or that they will not cause weight gain. Statistically speaking, I understand that these two are associated with less weight gain but I could be wrong.
Medication-related posts are for brainstorming purposes only. Talk to your doctor.
My meds: Parnate, Lamictal, Wellbutrin, trazodone