One thing just occurred to me. . .

For short term quick energy, look for dextrose tabs. Usually found in the pharmacy area of the supermarket in the "diabetic" section. Around here they come in pocket tubes of 10 tabs or plastic jars of 50. Different flavors, e.g. orange, grape etc. They are intended for diabetics, as a quick fix for low blood sugar. Each tab is 4 grams of glucose, and gets to the blood stream directly (no digestion required).

So, if you are hungry, a couple of these tabs will give quench your hunger very quickly and give you some energy. That and some plain water will get you going. I keep a tube in by car all the time.