Q. Where does the custom originate of throwing sweets on Bar-Mitzvah boys and bridegrooms in the synagogue?
A. In some places there once was a custom, on the Shabbat before a wedding, of showering the bridegroom with walnuts, almonds and dried fruits, symbolising the hope that the marriage should be fruitful and fulfill the commandment, “Be fruitful and multiply and replenish the earth” (Gen. 1:28).
The custom was later extended to Bar-Mitzvahs, not simply, one hopes, out of fun but to express the hope that the boy would be prolific in his observance of the commandments.
In places where unpackaged sweets or peeled nuts are thrown, Rabbi Chayyim David Halevi of Tel Aviv sees an infringement of the law of bal tash’chit – “you shall not destroy” (see Deut. 21:19 and Maimonides, Hilchot M’lachim 6:10). Rabbi Halevi says that when edible items are thrown, even in honour of a Bar-Mitzvah or wedding, much of the food becomes broken and wasted and is only fit to be thrown away.
He also criticises any use of food that makes it unfit for consumption, such as cutting vegetables and painting them, inserting vegetables as a decoration in an art work, or even using flour in order to make glue.
All of this is a form of bal tash’chit and should not be done if there is a practicable substitute.