When I read the subject line.... I thought 'not if you have some chocolate stashed in your sewing room' lol
But on the serious side. Yes one can diet and quilt. Some of the suggestions are wonderful. Another one - don't have your ironing board right next to the machine. Move Cut for awhile, then sew for awhile, and press for awhile. The key is to move. Sure it's not a 5 mile walk but you would be surprised by just moving around your room helps.