OK, so it's been years since I did long, all-day hikes - my kids are just now to the age where I'm able to get out more for longer treks.  Went out today to hike Signal Knob -great day, nice hike.  Ran into a problem.  I run 4 times a week and I am accustomed to eating a low amount of calories as a way to control my weight.  Went on the hike and I realized half way into it that I A) didn't eat enough for breakfast, and B) didn't bring enough to sustain me for the day.  Felt bad, cut it short and came back the same orange trail instead of making the loop.  Didn't really feel good again until about an hour after I had a meal.  Clearly I didn't consume or pack enough calories.  I'm so used to low calorie days, how can you estimate how much you should pack with you and eat without taking in too  much?  I'd rather not have that happen again, afterall, I'm out to enjoy the day, not half the day.

Thanks!