By Nellie Hedstrom, Extension nutrition specialist, University of Maine Cooperative Extension.Peer reviewers: Kathleen Savoie, Extension educator, and Jane Conroy, Extension educator, University of Maine Cooperative Extension. Updated in 2018 and 2021 by Kate Yerxa, Extension educator, University of Maine Cooperative Extension, and Sarah Perkins, University of Maine dietetic intern. For information about UMaine Extension programs