May one eat or drink after candle lighting?
Some Poskim rule it is permitted to eat or drink after candle lighting until Tzeis Hakochavim. Other Poskim rule it is forbidden to eat or drink anything after candle lighting. Nonetheless, if one is very thirsty, and is afraid to delay lighting candles until after she drinks, she may stipulate upon lighting the candles that she will not accept Shabbos with the lighting. In such a case, she may drink after lighting candles and is to then accept Shabbos within ten minutes from the lighting. If she did not make the above stipulation, some Poskim rule that in a time of need [such as a pregnant or nursing or ill or old person] she may nevertheless drink after candle lighting, up until sunset. Nonetheless, if possible, it is better for one to make Kiddush after candle lighting and then eat and drink to one’s content according to all opinions, rather than rely on the above ruling.
 Minchas Elazar 1:33; 2:11
 Peri Yitzchak 2:9; Ketzos Hashulchan 75 footnote 17 and 79 footnote 3 [leaves in question]; Beir Moshe 8:64
 Peri Yitzchak ibid [permits drinking all liquids and even to eat a little]; Daas Torah 271; Pischeiy Teshuvah 271 in name of Binyan Olam 7; Minchas Shabbos 77:2 [permits only water]; Ketzos Hashulchan 79 footnote 3; Beir Moshe 8:64; Mishneh Halachos 7:37; Piskeiy Teshuvos 271:13 [May drink any liquid and eat less than a Kebeitza of Mezonos]
 The reason: As perhaps the prohibition of eating or drinking before Kiddush does not begin to apply until sunset, as well as the Rambam always permits drinking water before Kiddush.
 Ketzos Hashulchan 79 footnote 3 in name of Minchas Shabbos ibid