When I don't want to take time or dirty a pot, I use Bear Valley Pemican Bars or Meal Packs. In a single bar, they have about 450 calories, using dried fruit, nuts and flower. No unpronounceables. (REI sells them on their web page, but I've had problems with running out at the stores. They are about $1.50 unless you buy them 12+ at a time when the price drops down to just over $1. REI will ship to your nearest store for pick-up and not charge shipping.) I add gorp, energy bars etc. for another 300 calories.

A good cereal meal is 1.5 c Quaker Oatmeal & raisins for 450 calories , with 2 pkgs Carnation Instant Breakfasts instead of milk for 125 calories. I add .25 cups or 5.8 oz raisins for another 125 calories. 700 calories will keep me going until lunch. I follow the European style and don't cook the oatmeal, so there is no messy pot to clean up.

BTW I've been told walnuts have the one of the highest ratios of calories per ounce for backpack foods, about 200 calories per .25 cup or 4.4 oz.