The Snickers bar is so tempting that you forget that it's been only two hours since that hamburger. Fifty cents later, wrapper unwrapped, as "she-ha-kol nihyah bi-dvaro" rolls off your tongue, you remember. What should you do? You can't take a bite, because you may not eat dairy less than six hours after meat. But you can't not take a bite, because you just made a bracha, and a bracha without eating violates the prohibition of bracha le-vattalah, a purposeless blessing.

The resolution of this and similar halakhic Catch-22's has been the subject of debate among poskim for many centuries, as the weighing of bracha le-vattalah against various issurei achilah (eating prohibitions) has produced an array of arguments and opinions. While this forum does not allow for a comprehensive discussion of all of the issues, we can summarize most of the central considerations.

The first issue to address, as it is common to all cases, is the gravity of the prohibition of bracha le-vattalah - the subject of a classic dispute between the Rambam and Tosfos. "Whoever makes an unnecessary bracha," says the Gemarah (Berachos 33a), "violates the prohibition of 'Io sisa [es shem Hashem elokecha la-shav}' ('do not take [the name of Hashem your God in vain]')." The Rambam [ Hilchos Berachos 1: 15] interprets this Gemara literally, that one who makes a bracha le-valtalah violates the Biblical prohibition of lo sisa. Tosfos [Rosh Hashanah 33a d"h ha], however, believe that the violation is only mi-de-rabbanan (Rabbinic). In our post-hamburger Snickers case, the Rambam's position points us quite strongly in the direction of allowing the person to eat, as eating would violate an issur de-rabbanan (milk after meat), while not eating would result in an issur de-oraysa. Tosfos's position leaves us with a still-open question.

Of the various cases of this type discussed by later poskim, the Rishonim address only one case - someone who made a bracha over food before making havda/ah on motza 'ei Shabbos, at which time it is forbidden to eat. "The Ritzba ruled that if a person forgot to make havdalah, and after he blessed 'ha-motzi' he remembered, if he makes havdalah [now] it is a hefsek (an interruption between the bracha and the eating, which invalidates the bracha); so, he should make havdalah and then make the bracha again." [She 'elos u-Teshuvos Maharam mi-Rutenberg 4:302.] For the Ritzba, preserving the issur achilah takes precedence, at the expense of violating bracha le-vattalah. Shiltei haGibborim [on the Mordechai, Berachos § 15] quotes a differing opinion: "The following appears in a responsum of the Geonim: . .. A person who forgot [to make havda/ah] and washed his hands and blessed ' ha-motzi,' ... should eat [some bread] and then make havdalah afterwards, so that he not invalidate the bracha of netilat yadayim and the bracha of ha-motzi." The Geonim explain that bracha /e-vattalah is of greater concern because it is not correctable, whereas even if one violates the prohibition of eating before havdalah, one may still say havdalah after eating. In other words, the inability of the eating-before-havda/ah prohibition to cause the forfeiture of the mitzvah indicates that the prohibition is somewhat weak; that weakness leads to its being overridden by bracha le-vattalah. In this case, the Rama [Orach Chayyim 271 :5] follows the Geonim, while the Magen Avraham [ibid. §12] appears to follow the Ritzba.

The Birkei Yosef [Orach Chayyim 561 :1] discusses the case of a person who made a bracha on a fast day. He quotes the Sefer Nechpeh beKesef, who believed that in this case there is actually a way to avoid violating either prohibition. The person should eat less than a ke-zayis of food. This ensures that the bracha was not in vain, as a bracha must be made on any amount of food; on the other hand, it does not violate the prohibition of eating on the fast day, as the ta'anis still counts if a person ate less then a ke-zayis. The Maharsham [Da'as Torah ibid.] argues forcefully against the Nechpeh beKesef, as he demonstrates that even eating less than a ke-zayis is forbidden on a fast day, at least le-chatechilah. And, he says, one should not violate the issur achilah actively (be-kum va 'aseh) in order to avoid violating the issur bracha le-vatta/ah passively (be-shev ve-al ta 'aseh), especially when the bracha /e-vatta/ah violation would be unintentional (be-shogeg) anyway. (Note that Sha 'arei Teshuvah [ibid.] and Maharsham both contend that the Nechpeh be-Kesef was only discussing a self-imposed fast, while on the four standard fast days even he would agree that one should not eat at all. She 'elos u-Teshuvos Mishneh Halachos [7:80], among others, points out that this distinction seems backwards, as a self-imposed fast could be a neder de-oraysa, while the four fasts are certainly de-rabbanan. Note also that if this were to happen on Ta 'anis Esther, one should almost certainly eat, as this fast is likely only a minhag.]

Rav Ovadiah Yosef [She 'elos u-Teshuvos Yabia Orner Yoreh De 'ah 2:5] addresses the case of making a bracha on dairy after eating meat. Analysis of this case requires that we understand the basics of the meat-dairy halachah. Mar Ukva [Gemarah Chulin I 05a] recounts his practice of avoiding eating dairy in the same meal as meat, always waiting le-se 'udasa acharisa - till another meal. (This practice is regarded by all later authorities as normative halachah.) Tosfos [ibid. d"h lese'udasa] explain that it is permissible to eat dairy even immediately after meat as long as a new meal is begun; this is accomplished by clearing the table and saying birkas ha-mazon. The Rambam [Hilchos Ma 'akhalos Asuros 9:28] and Shu/chan Aruch [Yoreh De 'ah 89: I] rule that one must wait the nor