Gemara

(Beraisa): The Chagigah brought with Korban Pesach is eaten first, so one will be satiated [with Kodshim] when he eats Pesach.

99b (Mishnah): On Arvei Pesachim one may not eat from shortly before Minchah until dark.

Question: Why does the Mishnah specify Erev Pesach? The same applies to any Erev Shabbos or Erev Yom Tov!

107a - Question: Does this mean shortly before Minchah Gedolah (which starts at six and a half hours of the day), or shortly before Minchah Ketanah (nine and a half hours)?

If it means before Minchah Gedolah, the concern is lest the meal get drawn out, and he will neglect to offer Korban Pesach;

If it means before Minchah Ketanah, the concern is lest he will be stuffed, and eating Matzah at night will be Achilah Gasah (gorging himself).

Answer (Ravina - Beraisa): Even Melech Agripas, who normally ate (began his first meal) during the ninth hour, may not eat until dark.

If it means before Minchah Ketanah, we understand why it says even Agripas (even though he has not eaten yet, and it is before the forbidden time, he may not begin because his meal will extend to when it is forbidden);

But if it means before Minchah Gedolah, why does it say even Agripas? (It is already forbidden to eat. Surely he may not begin!)

Conclusion: It means before Minchah Ketanah.

Question: Why does it say 'even'? His meal will extend to when it is forbidden (in such a case no one may begin)!

Answer: One might have thought that nine hours for Agripas is like four hours (the meal time) for common people. The Beraisa teaches that this is not so.

R. Asi ate Targima. R. Yitzchak ate dipped vegetables. Rava drank wine in order (to arouse appetite) to eat more Matzah at night. A Beraisa permits eating intestines.

Rav Sheshes used to fast.

Suggestion: Rav Sheshes holds that the Mishnah refers to Minchah Gedolah. The concern is Korban Pesach. He also holds like Ben Beseira according to R. Oshaya, who says that Pesach slaughtered in the morning of the 14th is Kosher, for its time is the entire day;

This opinion explains "Bein ha'Arbayim" to mean between the Erev of the previous day (after the end of the night, i.e. dawn) until (the beginning of) today's Erev.

Rejection: No. Rav Sheshes fasted because his nature was such that if he would eat (even earlier) during the day, he would not have appetite at night.

Rishonim

Rif (23a): One may not eat lest he will be stuffed at night and eating Matzah will be Achilah Gasah. Targima is fruits or legumes. Rava drank to make eating Matzah afterwards more pleasurable.

Rambam (Hilchos Chametz u'Matzah 6:12): Chachamim forbade eating Matzah on Erev Pesach for a Heker (to make it evident) that at night one eats for the Mitzvah. If one ate Matzah on Erev Pesach he is lashed mid'Rabanan until he dies. Similarly, it is forbidden to eat shortly before Minchah on Erev Pesach, in order that he will eat Matzah with appetite. One may eat a small amount of fruits or vegetables, but he should not fill up with them. Early Chachamim would starve themselves on Erev Pesach in order to eat Matzah with appetite, to endear Mitzvos to themselves.

Magid Mishnah: The Isur of Matzah on Erev Pesach is from the Yerushalmi. Rava drank in order to help him to taste Matzah.

R. Mano'ach: Only Matzah Kosher for the Mitzvah is forbidden; one may eat (Matzah made from) dough of Nochrim (40a). One who continues to eat after being warned is lashed until he dies; one who already ate is lashed less than 40 lashes, according to Beis Din's discretion. When he eats more Matzah at night, there will be no Heker to publicize the Nes (of Yetzi'as Miztrayim). It is as if he did not do the Mitzvah!

Rosh (10:19): We learn from Rav Sheshes that everyone must refrain from eating at a time that (based on his nature) will hinder his ability to eat at night. Maseches Sofrim cites a custom for firstborns to fast; a Yerushalmi supports this. Targima is Mezonos.

Tosfos (107b DH Dilma): Achilah Gasah is not considered eating. One is exempt for Achilah Gasah on Yom Kipur (Yoma 80b). However, in Nazir (23a) we say that one who ate Pesach Achilah Gasah was Yotzei, just not ideally! R. Tam says that there are two kinds of Achilah Gasah. If eating nauseates him, he is exempt on Yom Kipur. The other kind is when he has no appetite, but he tastes the food. Pesach is eaten when satiated, i.e. he has a little appetite to eat.

Tosfos (99b DH Arvei): If the text says "Arvei Pesachim", this is fine. (It refers to every Erev Pesach.) If the text says "Erev [Pesachim]", it refers to the afternoon during which we slaughter Pesachim. Alternatively, it refers to Erev Pesach Rishon and Sheni.

Question (Sefas Emes 99b DH Mai): If the Mishnah discusses also Pesach Sheni, why did the Gemara ask that the same applies to every Erev Yom Tov? Pesach Sheni is not Erev Yom Tov! Also, we should permit eating on Erev Pesach Sheni, since Pesach is eaten when satiated. On Pesach Rishon, there is an independent Mitzvah to eat Matzah. Ideally, it should be eaten with appetite. On Pesach Sheni, the only Chiyuv to eat Matzah is due to the Korban. If so, also Matzah is eaten when satiated!

Poskim

Shulchan Aruch (OC 471:1): One may not eat bread from (the beginning of) the 10th hour in order that he will be able to eat Matzah with appetite. It is permitted to eat fruits or vegetables, but he should not fill up with them.

Rema: If one's nature is such that even eating a little spoils his appetite, everything is forbidden to him.

Shulchan Aruch (ibid.): One should not drink a small amount of wine, for this satiates. One may drink a large amount, for this arouses appetite.

Beis Yosef (DH u'Mah she'Chasav Rabeinu): Agripas used to eat at nine hours and again at night, therefore, one might have thought that he may eat at nine hours. The Beraisa teaches that this is not so. Here, Targima does not refer to Mezonos, for Mezonos satiates!

Bach (DH u'Mah she'Chasav Yayin): The Mordechai permits to drink between the first two cups at the Seder, for with the two cups this is much wine, and it arouses appetite. The Tur permits drinking a small amount during the day, for he holds that it joins with the first two cups. Others forbid, for there is a delay in between.

Mishnah Berurah (6-7): Drinking two cups is a lot. It is permitted at any time. Presumably, drinking less than a cup, or in any case less than half a cup is permitted, for it is too little to satiate.

Mishnah Berurah (2): If one started eating after nine hours, he must stop.

Kaf ha'Chayim (2): Even less than a k'Zayis of bread is forbidden.

Kaf ha'Chayim (5): The Rama (639:3) forbids eating after midday on Erev Sukos, in order that one will eat at night in the Sukah with appetite. He did not write this stringency regarding Erev Pesach, for in any case Chametz and Matzah are forbidden. Matzah Ashirah is not satiating, and further it is our custom not to eat it, lest it became Chametz! Alternatively, we are less stringent about Erev Pesach because it usually takes a long time to say the Hagadah before eating Matzah; also, the first two cups arouse appetite.

Kaf ha'Chayim (9) Tosfos (Eruvin 55B DH Kol) says that raw vegetables arouse appetite, but even a small amount of cooked vegetables satiates. Perhaps this is only when they are eaten with bread. We are not stringent to refrain from them.

Kaf ha'Chayim (15): Surely, drinking to satiation ruins appetite (Taz). Also, perhaps it will befuddle him, and he will not perform the Seder properly.