Believing newlyweds brought good luck, guests used to shower them with nuts and grains to insure a bountiful harvest and many children to work the land. During years of a poor harvest, rice was tossed instead. This tradition continues today with rice or birdseed (where permitted), or bubbles to wish the Bride and Groom much happiness. Incidentally, it is only a superstition that birds eating rice thrown after a wedding ceremony are destined to have their stomachs enlarge and eventually explode. This myth may have simply evolved from church/synagogue employees weary from cleaning after every wedding ceremony!