Is Chelsea Clinton really greening her wedding menu with vegan dishes and grass-fed organic beef?Chelsea Clinton has known fiancee Marc Mezvinksy a long time as shown in this Dec. 1996 photo of them sitting in Hilton Head Island, S.C. That's the word from Ecorazzi, an online gossip site, which reports that an "insider" told Life & Style magazine: "Chelsea is a vegan. The food will include vegetarian, vegan, and gluten-free dishes, but there will also be grass-fed organic beef on the menu."