Okay, I like that!
I spent years working outside (no convenient refrigerator) dealing with problems like that:
1. Evelyne- for fast food I eat Shawarma! I ask for Shawarma (with extra fat yummy) salad fried eggplant in a pita. I eat the inside and throw away the pita.
I do everything possible with eggs for breakfast. I even make pancakes using only cinnamon. What kind of ideas are you looking for?
I just consider high carb foods "not kosher" and that's it. No temptation. Since starting Atkins TZL my problem has been fruit. (beforehand it wasn't sweet enough!) I planted lots of fruit trees and the ripe fruit grown in my yard is so tempting!
2. Linda - Hiking the National path is a dream come true! I wish I could come with you! Let me know when you reach the Negev - you are invited! On trips I take with me cans of tuna. If I don't think I will have anywhere to drain the oil I bring tuna or salmon paste. I eat it with a spoon of course. Hard vegetables like cucumbers, celery and fennel goes nicely in bags and don't spoil. If it is not too hot I will take hard boiled eggs with me. Low carb energy bars, a bit expensive but light weight. Whey powder - just mix with water. There are a few soy-flour based items sold at health food stores that are relatively low carb and light weight, like "soycrunch". Sugarless halva.
I hope this helps!
Hag Sameyah!