“The diet starts tomorrow!” If you’ve ever forsworn a specific type of food when making this declaration, and then attempted workarounds in order to eat something similar and not officially consider it cheating, the mishnah at the top of today’s daf will likely speak to you.
In the case of one who vows that cooked foods are forbidden to him, he is permitted to eat roasted and boiled foods.
It’s difficult to read this mishnah without imagining that the one who has sworn off cooked foods is seeking workarounds by eating food that has been roasted or boiled (which, apparently, doesn’t “count” as cooked). The Gemara knows of another source that is skeptical of this method of upholding a vow not to eat cooked food:
It is taught in a beraita (early rabbinic teaching): Rabbi Yoshiya maintains that he is prohibited from eating roasted foods. And although there is no biblical proof of the matter, there is an allusion to the matter, as it is stated: They cooked the paschal offering with fire, as prescribed … (II Chronicles 35:13)
How do we know that roasted food falls under the category of cooked food (in addition to common sense)? A biblical proof is brought from II Chronicles, which outlines the practice of offering the paschal sacrifice in the Temple and distributing the food to the people afterwards. The verb used in this sentence is “cook” — the same as in the vow in our mishnah — but the method of cooking is undeniably roasting over a flame. The word “fire” in this verse is the same word that is used for roasting in the mishnah. Therefore, argues Rabbi Yoshiya, the person in our mishnah who vows not to eat cooked food should be prohibited from partaking of roasted food as well.
The Gemara looks for the root of the disagreement between Rabbi Yoshiya and the mishnah:
Let us say that they disagree with regard to this following principle: Rabbi Yoshiya holds that one should follow the language of the Torah, and the author of our mishnah holds that with regard to vows one should follow the language of people.
Perhaps the disagreement is this: Rabbi Yoshiya suggests that we should follow the language of the Torah, but the mishnah follows the language of the people, who in each time and place understand these terms differently.
However, the Gemara rejects this explanation of the difference between the mishnah and the beraita:
No, everyone agrees that with regard to vows one should follow the language of people. Rather, this sage stated his opinion in accordance with the language of his locale, and this sage stated his opinion in accordance with the language of his locale.
No one thinks vows should always rely on the language of the Torah, but they should always reflect local language. People should intuitively understand what they are vowing — and so should those who hear them make the vow. The beraita and the mishnah, the Gemara asserts, are in agreement on this point. Therefore, it must be the case that in the locale of the Tanna who taught our mishnah, roasted food is not considered to have been “cooked” (the verb had a narrower range of meaning), while in the locale of Rabbi Yoshiya roasted food is considered to have been cooked.
So does roasting count as cooking? It all depends on what “cooking” means in your time and place. So be careful what you swear to, because in our day roasting and boiling (and likely frying, baking, pressure cooking and “air frying”) all fall into the category of cooking, since that is the language of our time. It’s a good thing, then, that “the diet starts tomorrow!” probably isn’t enforceable as a vow.
Read all of Nedarim 49 on Sefaria.