In Nishmas said on Shabbos and Yom Tov mornings we say, “you redeemed us from Egypt and delivered us from the house of bondage; you fed us in famine” (all describing times of trouble) “and sustained us in plenty” (not normally thought of as a time of trouble), “you delivered us from the sword saved us from the plague and spared us from serious and lasting illness” (more trouble).

What is “and sustained us in plenty” doing there?