Despite their high cost I find nutritional bars make good trail food for several reasons.
1. They offer a source of vitamins, protein, carbs, and fat.
2. They taste good enough to be sort of a treat but not so good that you would be likely to binge on them.
3. They are a convient food for when you don’t want to eat breakfast but just need to get hiking right away to avoid the heat.
4. They ride well in your pocket and are handy to have there when you need to eat something but you don’t want to stop, like when it is raining.
I usually pack 2 bars for every day I will be out on the trail.
If it will be really cold, be conscious that some bars freeze rock hard and will be impossible to eat.