Australian Rabbi Mendel Kastel is publishing an online guide for dieters, complete with kosher recipes without fattening kosher foods. "Bagels, chopped liver, matzo balls, schmaltz herrings--there are things in a kosher diet that make us put on weight," he said. "Rather than a white bagel, try a whole meal one."

Rabbi Kastel, who also is head of an Australian rabbinical council, sent a message to Australian Jewish communities to encourage dieting. Corporate sponsors are offering to donate a dollar to a crisis housing agency for every kilogram (2.2 pounds) that people shed.

"We aim to lose about a kilo a week. So we are looking for 100 people to lose 10 kilos each. And the more, the better," he told the Sydney Herald.