One of the things people often overlook is that Christians who practice regular fasting, as in Lent and Advent, are much better prepared to face low supplies than those who don't.
The Lenten exercise has always been the best training for a good survival morale. You learn to focus your thoughts on God and get your strength there without feeling panicky over lack of specific items that you are in the habit of having.
Panic will destroy the first wave of people, and a lot of it will be completely needless panic. Catholics who have learned the spirit of poverty and who have engaged in even small sacrificial fasting will have a much less stressed reaction to periods of low supplies.
Less stress means we will use up our internal energy supplies more slowly and we will remain clear-headed and be able to solve problems as they arise.
Everyone should practice serious fasting at least once or twice a month, IMHO, just to be prepared, and we know that fasting together with prayer is spiritually powerful, too.