1,134. Eating Matzah, and Eating in General, on Erev Pesach

Chometz u’Matzah 6:11

There is a rabbinic enactment not to eat anything after the matzah, not even roasted seeds, nuts or similar such things. Even if one already ate matzah, if he subsequently ate other food, fruit, etc., he must eat another olive-sized portion of matzah afterwards and then stop eating.

Chometz u’Matzah 6:12

The Sages prohibited eating matzah on the day before Passover in order to distinguish between eating it generically and eating it to fulfill the mitzvah. One who eats matzah on the day before Passover is given the stripes administered for acting rebelliously. It is likewise prohibited to eat on the day before Passover starting close to time of mincha so that one will eat matzah with an appetite. One may snack on fruits or vegetables but he may not fill up on them. The Sages of previous generations would deprive themselves on the day before Passover in order to eat their matzah with a hearty appetite because of their love for the mitzvos. On the day before Shabbos and other holidays, however, one may keep eating until nightfall.