Really...it does. Especially during a time of great stress. Various preparedness authors recommend packing away things like Snickers...Reeses Pieces...Cheetos...and a plethora of other "junk food" in one's emergency stash of food because "These foods cause the brain to release natural opiates, which in turn decrease pain and create euphoria and your body learns to gravitate toward them." (Levine, Kotz, Gosnell - 2003).
If you are driven from your home because of a disaster...and you are sitting in a noisy building with a bunch of other people who have been evacuated...stressed out and worried...are you going to want to reach into your emergency bag and pull out some health bar that tastes like cardboard...or a chocolate pudding and some corn chips? The experts would say to eat the junk food...or more aptly put...the "comfort" food....as short term you will be better off. It will serve to ease your troubled mind.
Barbara Salsbury gives some great examples in her book "Time to Prepare Not Panic"of some comfort foods to put into an emergency pack that are lightweight. If you are packing a lot of stuff for an emergency...keeping everything lightweight is a good idea...as you may have to carry it for a long distance.
While it is certainly not advisable to eat junk food for the main course of ones diet long term...as it could make you fat...unhealthy...and starved of good nutrition...Vicki Tate would say that to NOT include junk food is a food storage mistake. She says that if you are living on food storage..."Psychological foods" "make it more bearable". They also serve to add variety to your diet which reduces the chance of appetite fatigue (where you are sick of eating the same thing).
It is possible to freeze some candies to increase their shelf life...as well as some other methods...but most have a shelf life of less than a year. This makes a rotation plan important. I'm sure there are some children who would be happy to help...just make sure that they don't sneak your candies without your knowing or you may not have it when you need it!
Personally...just about the only candy we buy is for Halloween. We purposefully purchase the candy that WE like to eat...so that if we have leftovers...it will go into our emergency stash. Don't tell my kids...but a lot of their candy from trick or treating ends up in our stash too!
So...add some junk to your emergency evacuation kits...and your home storage and find some of the comfort that only junk food can give!