As I mentioned elsewhere: hydrate, hydrate, hydrate!, and remember to replenish electrolytes with fluids like Gatorade.
Nutrition is an important part of my search strategy because I have an odd eating habit. I only eat until I am not hungry. I never eat until I am full. I hate the drowsy feeling of being to real full. The moment I no longer feel hunger, I stop, even if I have only taken 2-3 bites of a sandwich. I will eat more when I feel hungry again, usually in about an hour. As a result, I eat 10-12 times a day in these small portions. This keeps me light on my feet and never bogged down. My family say I graze.
It may be beneficial for you always to carry some source of quick energy carbohydrate in the field especially if you have a physiology like mine. I weigh 150 pounds, and do not have a lot of body fat, so with my eating habit, I often run out of gas on a strenuous hike. I always pack protein bars and snacks, but I can still run out of energy. I can quickly use up the glucose in my blood and even deplete stored up glycogen. At that time I hit a wall, and feel dead tired. This concerned me at first, but I now know it is simply a blood sugar issue. To deal with this, I always carry a small bottle of honey in my backpack. Whenever I feel that tired heaviness, I gulp down two big mouthfuls of honey and a pint of water. I find a shady spot, lie down and check the time. Predictably within 15 minutes the heavy cloud of tiredness lifts and I’m good to go again.
On one field trip I did all of the above and surprisingly I did not feel better. At the time I was with a small party of colleagues working on my T-Rex site. One had brought a friend to the site who happened to be a nurse….very convenient. She described the issue was not sugar or hydration. This time it was my electrolyte balance. They offered me a bottle Gatorade. I chugged it down and in a few minutes I was okay again. Lesson learned. Now I also carry Gatorade, water and instant IV packets.
Always listen to your body and be safe.