If I spend a couple hours a day grocery shopping and delivering (volunteer) will I lose weight?

I weigh 215 lbs and should weigh 150 lbs. I'm fifty, female and otherwise in good health. But I take tegretol for bipolar disorder, and it seems that it causes weight gain, as recently I decreased it for a week and lost five pounds, and when I went back on the higher dose it all came back. So I'm battling that problem. Exercise seems to be a good method in general; will this exercise in particular help me lose weight?