When sitting at the right places and dishes are served, it is time for the guest of honor to take the first drink or propose the first toast. It is the guest of honor who should be the first to begin eating.
Generally, the guest of honor will invite everyone to begin eating with words to the effect of "Shall we eat?" This gesture of politeness serves as a signal to the other guests that they may then begin dining.
It is unforgivably rude to eat before the guest of honor has begun to eat, so although the guest of honor invites the other guests to begin dining, no one does so until the guest of honor has taken the first bite.