This might be a difficult question to answer because everyone will react differently to the various medications.
However...there has been some research on this and I wrote a post, Which antidepressants are least likely to cause me weight gain?
At the top of the list is Wellbutrin for not being reported to cause so much weight gain. Probably one of the worst meds to cause reported weight gain is Paxil.
The best person to discuss your options,of course, is your doctor.
Hope this helps some! Thank you for your question.