Answer:
1. to beg for forgiveness in a very humble way =eat humble pie, eat crow, eat dirt
2. to dejected or unhappy= eat one's heart out
3. to withdraw what you have said=eat one's word
4. to eat tremendous amounts of food= eat away
5. to give one no trouble; do whatever ones wishes= eat out of one's hand
6. to nibble or gnaw at= eat their heads off