If the weight gain was due to the Zoloft, it should come off very quickly without you doing anything differently. If it doesn't come off within the next three months, then it might be due to other things, including the possibility as you age your body shape is changing or that, as you age, what you call eating "normally" isn't normal for you. But my guess is, again, if this is due to the drug the weight will just come off fairly quickly.