From where does that saying of folk come: "Sixty runners ran, yet they could not overtake the man who breakfasted in the morning"? And the Rabbis said: Rise early and eat, in summer because of the heat and in winter because of the cold. As it is written, "They shall not hunger nor thirst, neither shall the heat nor the sun smite them" (Isaiah 49:10). He said to him: You speak from there, and I speak from here: "And you shall serve the LORD your God" (Exodus 23:25), this is the recitation of the Shema and the Prayer; "and He will bless your bread and your water," this is bread with salt and a pitcher of water. From this point onward, "and I will remove sickness from your midst." And it was taught: "sickness" [mahalah], this is bile. And why is its name called mahalah? Because there are eighty-three illnesses in it, and "mahalah" in gematria is exactly that number [the letters of mahalah total eighty-three]. And all of them are nullified by bread with salt in the morning and a pitcher of water.
Bread and Salt in the Morning Wards Off Eighty-Three Illnesses
Yalkut Shimoni on Torah 359:10
מִנָּא הָא מִלְּתָא דְּאָמְרִי אִינְשֵׁי, שִׁיתִין רָהִיטִי רָהוּט, וְלָא מָטוּ לְגַבְרָא דְּמִצַּפְרָא כְרַךְ, וְאַמְרֵי רַבָּנָן, הַשְׁכֵּם וֶאֱכֹל בַּקַּיִץ מִפְּנֵי הַחַמָּה וּבַחֹרֶף מִפְּנֵי הַצִּנָּה. דִּכְתִיב (ישעיה מט, י) "לֹא יִרְעָבוּ וְלֹא יִצְמָאוּ וְלֹא יַכֵּם שָׁרָב וָשָׁמֶשׁ". אֲמַר לֵיהּ. אַתְּ אֲמַרְתְּ מֵהָתָם, וַאֲנָא אֲמִינָא מֵהָכָא, וַעֲבַדְתֶּם אֵת ה' אֱלֹהֵיכֶם, זוֹ קְרִיאַת שְׁמַע וּתְפִלָּה, וּבֵרַךְ אֶת לַחְמְךָ וְאֶת מֵימֶיךָ, זוֹ פַּת בַּמֶּלַח וְקִתּוֹן שֶׁל מַיִם, מִכָּאן וָאֵילַךְ, וַהֲסִרֹתִי מַחֲלָה מִקִּרְבֶּךָ, וְתַנְיָא, מַחֲלָה, זוֹ מָרָה, וְלָמָּה נִקְרָא שְׁמָהּ מַחֲלָה, שְׁמוֹנִים וּשְׁלֹשָׁה חֳלָאִים יֵשׁ בָּהּ, מַחֲלָה בְּגִימַטְרִיָּא הָכֵי הֲווּ, וְכֻלָּן פַּת בַּמֶּלַח בְּשַׁחֲרִית וְקִתּוֹן שֶׁל מַיִם מְבַטַּלְתָּן.