Eating Before Kiddush Friday Night-
1) After sunset on Friday evening, it is forbidden to eat or drink until Kiddush is said. (S.A. 271:4) If one accepts Shabbos before sunset, the prohibition goes into effect as soon as he accepts Shabbos. (M.B. 11)
2) Therefore, women may not eat or drink after lighting the Shabbos candles until she either hears or recites kiddush, since lighting the candles generally constitutes acceptance of the Shabbos for them. (Magen Avraham 5)
3) If a woman is thirsty, she may drink water after lighting candles if it is still before sunset. In case of necessity she can even drink tea during this time. (Shemiras Shabbos K’Hilchoso 43:46)
4) If at the time of candle-lighting she has a strong craving for food or drinks, and water or tea would not suffice, she should have in mind that by lighting the candles she is not yet accepting Shabbos upon herself. She is then allowed to eat or drink until sunset. (ibid.)
5) If a person must take medication after candle lighting and prior to kiddush (it is not always permissible to take medication on Shabbos, for details a rav should be consulted), he may drink water with it to help swallow the pill. (ibid. 52:3)
Eating Before Kiddush Shabbos Day–
1) One may not eat or drink anything, even water, before hearing or reciting kiddush on Shabbos day. (S.A. 289:1) The kiddush obligation of Shabbos morning does not take effect until after one has prayed Shachris.
2) Since before davening one is not yet obligated to make kiddush, one is permitted to drink water, tea and coffee before davening. (See Aruch Hashulchan 89:23, Halichos Shlomo 2:3, Yabia Omer vol. 9 page 237 and Shulchan Halevi 7)
[May one drink orange juice before davening? The Sefer Avnei Yashfei (5:14) writes that one should be stringent and avoid drinking all fruit and vegetable juice before davening. However, in the sefer Piskei Rav Belsky zt”l (page 31) it says in the name of Rav Belsky, “Regarding orange juice, the minhag is to be lenient, thus it is permitted before davening.” Rav Belksy is further cited, “Hot cocoa is a rich drink made with a lot of milk, and therefore it is not permitted for adults prior to davening. Children may drink hot cocoa before davening, as is a common incentive in camp. Cappucinos, and iced coffee made with a lot of milk are not permitted either.”]
3) The poskim debate whether a weak person who must eat bread, cakes or cookies before davening shachris should recite kiddush before eating or may he eat without kiddush.
A- According to some poskim, including the Divrei Yetziv (132:3) and Harav Ben Tzion Abba Shaul zt”l (Ohr Ltzion vol. 2 page 185), the ill person may eat without reciting kiddush. They feel that it is not halachically possible to recite kiddush before shachris, therefore, he or she may eat without reciting kiddush.
B- However, according to others, including the Mishnah Berurah (see Biut Halacha 289), a weak person who must eat something before davening must first recite kiddush. Since a weak person is permitted to eat even before davening, the obligation to make kiddush has already taken effect , and he must therefore make kiddush before eating. The Shemiras Shabbos K’Hilchoso (52:12) adds that it would be preferable for the ill person to at least recite Birchas Hatorah and the first paragraph of Shema before he eats.
C- Rav Moshe Feinstein zt”l (Igros Moshe 4:101:2) agrees with the aformentioned view of the Mishnah Berurah. Yet he writes that there is a difference between an ill married woman and an ill single woman. He explains that an ill single woman must make kiddush before eating, however, a married woman who is ill may eat without kiddush as long as her husband has not yet prayed shachris. Once the husband prays shachris she must recite kiddush like everyone else. Harav Moshe reasons that since a married woman is required to eat the Shabbos meal with her husband, she does not become responsible to make Kiddush until it is time for the two of them to eat the Shabbos meal together, meaning after he has davened shachris.
D- Harav Ovadia Yosef zt”l (Chazon Ovadia Shabbos vol. 2 page 149) discusses this issue at length and he concludes that an ill person who is eating before shachris should recite kiddush before eating and then should recite kiddush a second time following davening.
4) If the person feels ill and just needs to eat fruit before shachris, and not bread or cake, he should eat without reciting kiddush. (Shemiras Shabbos K’Hilchoso ibid.)
5) As noted above, the obligation to recite kiddush begins after one davens shachris. The question is for women what is the definition of “shachris” in regards to the obligation to recite kiddush.
A- All authorities require a woman to daven daily, but there is a dispute whether she is required to recite the full shemoneh esrei, or whether she fulfills her requirement by reciting a simple prayer, such as the birchas hashachar. The common practice amongst women is to adhere to the stricter view and therefore they recite birchas hashachar and shemoneh esrei of Shachris. (See M.B. 106:4)
It is well known that one may not eat during the week before davening shachris. According to the first opinion that a woman is required to recite the full shemoneh esrei, she may not eat breakfast in the morning without first davening, whereas according to the second opinion that she fulfills her requirement once she has recited a simple prayer or morning berachos, she may eat breakfast during the week once she recited these tefilos. Many women follow this second view and during the week they recite brachos, eat breakfast and then recite the remainder of shachris later on.
The Sefer Tosefes Shabbos (286:4) argues that this leniency during the week actually may become a stringency on Shabbos. Some authorities rule that a woman becomes obligated to hear Kiddush as soon as she recites berachos, since she has now fulfilled her requirement to daven. According to this opinion, once she recited berachos on Shabbos morning, she may not eat or drink without first making Kiddush. This approach contends that before she recites morning berachos, she may drink water, tea or coffee, but after she recites morning berachos, she may not even drink these beverages without first reciting Kiddush.
Similarly, the Shemiras Shabbos K’Hilchoso (52:13) rules that a woman who during the week will eat breakfast after reciting brachos (and either doesn’t pray the shemoneh esrei of shachris or does so after breakfast), must then recite kiddush on Shabbos after reciting brachos. After she recites brachos she may not drink even water without first reciting kiddush. Harav Ahron of Belz zy”a (cited in Halichos Bas Yisroel page 223) is also cited as ruling that once a woman recites birchas hatorah she cannot eat without reciting kiddush.
6) The Kaf Hachaim (286:30) contends that the above is only true if a woman intends to fulfill her obligation with brachos alone. However, a woman who plans on davening the full shachris can follow the same approach that men follow, and may drink water, tea or coffee even after she recited berachos before she has davened. He explains that if a woman does not intend to fulfill her obligation of praying with brachos alone and she intends to pray shemoneh esrei, they may still drink water and tea.