According to the vast majority of poskim there is no Mitzvah to risk your life to save others.

I'm sorry but your comment has nothing to do with the question at hand, for as we wrote previously, in the worst case, you must bring your own food from home, either to the army or to yeshiva, but the complaint of bad or even (theoretically) dangerous food doesn't exempt from either the mitzva to learn in yeshiva or similarly, to serve in the army. In addition, even theoretically, you should know that the generally accepted halacha that there is no mitzva to risk your life to save others, obviously doesn't apply in the Israeli army, where that's an inevitable part of war. King David, Yehoshua, Gidon, Shimshon and all kings, all risked their lives during the many wars throughout the Bible to save Am Yisrael, because that's the only mitzva which supersedes even the 3 cardinal sins of idolatry, adultery (as seen from Yael and Esther) and murder (including giving one's own life!), see sources in https://asif.co.il/wpfb-file/2-13-pdf/. In short, even theoretically, the premise of your question is mistaken, for the laws of battle are halachically different than all other situations, for without mesirut-nefesh (self-sacrifice) and risking our lives, we never would have had the Land or State of Israel, not in Tanachic times, and not today! This altruism (selfless giving) in the IDF is a major foundation in Judaism & another reason to davka draft into the army, in striving to be like God Who created the world, even though He is perfect & doesn't lack anything, yet wanted to give idealistically, altruistically.