It is a mitzvah to have a festive meal on Purim, which includes meat and wine.
This festive meal should be held during the day; if one ate this meal at night, he has not fulfilled the obligation. However, on the night of the fourteenth of Adar after the Megillah reading - or on the night of the fifteenth in the cities that celebrate Purim then - one should also rejoice and eat a more elaborate meal than usual. The table should be set and candles lit. One should wear holiday clothing when eating at night, and surely when partaking of the festive meal during the day.
It is customary to schedule the festive meal for the afternoon of Purim. Minchah is recited in the early afternoon and the meal is extended into the night. Most of the meal, however, should be eaten during the day.
If Purim falls on a Friday, the festive meal is held early and should be concluded well before Shabbat so that one can enjoy the Shabbat meal that evening with good appetite. Some have a tradition of eating the festive meal later in the day on Friday and extending it until Shabbat arrives. They then place a Shabbat tablecloth on the table, recite Kiddush, and continue the meal, which now becomes a doubly festive meal, in honor of Shabbat as well as Purim.
The miracle of Purim is inextricably linked with wine. Vashti' downfall occurred at a feast of wine, and Esther took her place. Haman' downfall occurred at the feast of wine which Esther made. This feast of wine served to rectify the transgression of the Jews who participated in the feast of wine made by Achashverosh.
Our Sages, of blessed memory, therefore ordained that one should drink wine until the point of intoxication on Purim. They must drink on Purim until he cannot differentiate between said: One must drink on Purim until he cannot differentiate between "cursed is Haman" and "blessed is Mordechai."
However, if one's health might be impaired by drinking wine, or if one fears that becoming intoxicated might lead him to act irresponsibly, or that it might lead him to neglect to say the proper blessings and prayers, he is not required to drink till intoxication. Rather, he should drink more than he usually does and when he falls asleep because of that he will have fulfilled the obligation, for one who is asleep cannot differentiate between curses and blessings.
It is customary to eat vegetables on Purim, in commemoration of the fact that Esther ate vegetables when she was in the king's palace for she was uwilling to eat the non-kosher food served there. The verse states. And he differentiated for her and for her maidens for good (Esther 2:9) i.e., he gave her food that was different and that was good for her. This was also true of Daniyel, Chananyah, Misha'e and Azaryah when they were in the royal household in Babylon they also subsisted on vegetables alone.
Although it is laudatory to eat an elaborate meal on Purim, it is preferable for one to be more generous in giving gifts to the poor than in making an elaborate meal or exchanging gifts of food with friends. There is no greater joy or more praisworthy action than making the hearts of the poor, the orphaned, or the widowed happy. One who brings joy to their hearts is compared to the Shechinah, as the verse (Isaiah 57:15) states: "(G-d) revives the spirit of the oppressed, and restores the heart of the downtrodden (Rambam, Hilchot Megillah 2)".