[I'm in fact slightly concerned because that doesn't match my model of how anything on my world works metabolically - there could still be food in my intestines and my body's caloric reserves would release sustained triglycerides and later ketones into my bloodstream over time - but if the issue doesn't arise until summer there'll be time for me to check for metabolic differences; if your world's metabolic setup looks the same as mine, I'll chalk it up to 'magical rules rather than actual caloric dependency' and... does your civilization understand why the rules are that way, or is it just empirically observing the 2-day limit on food?  Because it's also never observed somebody go through their first eclipse at an age much higher than 12.  I mean, maybe this isn't the most urgent question, but it sounds like something you or your world worries a lot about, and the thought does come to mind.]

[I'm in fact slightly concerned because that doesn't match my model of how anything on my world works metabolically - there could still be food in my intestines and my body's caloric reserves would release sustained triglycerides and later ketones into my bloodstream over time - but if the issue doesn't arise until summer there'll be time for me to check for metabolic differences; if your world's metabolic setup looks the same as mine, I'll chalk it up to 'magical rules rather than actual caloric dependency'.  Actually... does your civilization understand why the rules are that way, or is it just empirically observing the 2-day limit on food?  Because it's also never observed somebody go through their first eclipse at an age much higher than 12.  I mean, maybe this isn't the most urgent question, but it sounds like something you or your world worries a lot about, and the thought does come to mind.]