It is forbidden to eat something before Shaharit unless one is sick. If one is not feeling well on Shabbat morning and must eat something before Shaharit, does he make Kiddush at this point?
The opinion of Hacham Ovadia Yosef and the Be’ur Halacha (Rabbi Yisrael Meir Kagan 1839-1933) is, that a sick person who must eat on Shabbat morning before Shaharit should make Kiddush and drink the wine. Hacham Ovadia Yosef writes that even though he made Kiddush before Shaharit he should make another Kiddush after Musaf to please those opinions who say that the obligation of Kiddush comes after Musaf. Hacham Ben Sion Abba Shaul (Israel 1923-1998) writes (Or Lesion Helek 2) that in such a case where one is sick and he must eat something before Shaharit, he should eat without reciting Kiddush.
Although eating and drinking are forbidden before Shaharit on Shabbat, may one eat and drink after Shaharit but before Musaf? A number of Poskim maintain that the obligation of Kiddush does not take effect on Shabbat morning until after the recitation of Musaf. Therefore, once a person recites the Amida of Shaharit, he is permitted to eat and drink. Others disagree, that the obligation of Kiddush begins after Shaharit, not after Musaf, and therefore, after one recites the Amida of Shaharit on Shabbat, he may not eat or drink anything until he recites Kiddush.
In light of this debate, Hacham Ovadia Yosef rules in Yabia Omer that one should not eat after Shaharit before Kiddush unless there is some pressing need. For example, if somebody feels a bit week or frail and needs a snack or drink, then he may eat or drink. Other examples include a Baal koreh whose voice is hoarse and he needs to drink water to be able to read properly, and somebody who needs to take medicine at a certain time with food or drink. These are all legitimate needs that allow for relying on the lenient position of eating and drinking before Kiddush. Otherwise, however, if one feels well and has no particular need to eat or drink, he should refrain from eating and drinking until he recites Kiddush. The Hi"da (Rabbi Haim Yosef David Azoulai, 1724-1807) writes that one who made Kiddush in between Shaharit and Musaf, should make it again after Musaf to satisfy the opinions that say Kiddush takes effect after Musaf.
