The melaveh malkah, the Saturday night meal bidding Shabbos farewell after its completion, has long suffered widespread abandonment. Despite its codification in Jewish law (Shulchan Arukh, Orach Chaim 300:1), many otherwise observant Jews observe it minimally, if at all. This can be somewhat explained by the difficulty of eating a meal when Shabbos ends very late, mentioned already in the seventeenth century by the Magen Avraham (300:1). I suggest that such practice is justified and that minimal observance of the meal, which we will explain shortly, is actually a stringency.
Kabbalists see mystical value in the melaveh malkah. Accordingly, Chasidim emphasize its importance and maximize its observance. They generally eat a full meal, replete with bread and meat. Non-Chasidim who observe kabbalistic customs, such as followers of the Vilna Gaon, also embrace the melaveh malkah as a full, festive meal. However, mainstream Orthodox Jews tend to eat whatever they desire, if anything.
Shulchan Arukh (ibid.) lists the order of preference for foods in this meal. Many people do not eat any bread, which is at the top of the list, and instead eat food with the blessing of mezonos. Others eat fruit or vegetables, and still others drink hot beverages. And some people eat nothing because they are not hungry. Do all these people reject an explicit law and adopt either unpreferrable or unacceptable practices?
The Eliyahu Rabba (340:1 – link) records an important leniency he “heard.” He reports a ruling that any food eaten after sunset on Saturday counts for melaveh malkah. Therefore, someone who begins “Shaleshudis,” the third Shabbos meal, close to sunset and continues eatin has fulfilled the requirement of melaveh malkah. Significantly, the Ba’eir Heitev (340:1 – link) quotes this view without dissent. The Arukh Ha-Shulchan (340:3 – link) also adopts this position as normative. The Shemiras Shabbos Ke-Hilkhasah (63:6) quotes it and adds that some disagree.
If this lenient view is normative, then the common practice of beginning Shaleshudis right before sunset obviates the need to eat melaveh malkah. If so, the practice of eating food with the blessing mezonos or drinking a hot beverage as melaveh malkah is actually a stringency. Even though you have fulfilled your obligation, you are eating or drinking something “just in case,” as a chumrah.
Please note that I fully recommend this stringency, and practice it myself. The Arukh Ha-Shulchan adds that during Shaleshudis you should eat a minimal measure (ke-zayis) of bread after sunset so that you legitimately eat a meal during the night. While the other authorities do not mention such a requirement, it seems to me to be a stringency that is easy to fulfill if you start Shaleshudis close enough to sunset.