Since this is Light Food Talk I’m surprised not to see more discussion of nutrition content per gram. Here is what I do: examine the label on a package of walnuts, for example, and note the calories, carbs, and fat versus the total weight. Do this for all your food items. You can plan a day’s food around this process and calculate exactly what to carry to get 3500 calories total, for example, including some reasonable balance of protein, fats, and carbs. Using the guide of 9 calories per gram for fats you might just bring olive oil to condense many calories into a light meal, and in fact I do just that, add olive oil to every dinner to pack on more calories while keeping pack weight low. This can get pretty complex so unless you keep your meals simple or eat the same thing each day it mitght be too much trouble. For long trips where you want to keep weight at a minimum, it does pay off. And you can use the same menu next year, making more sense of your time investment. Use 9 calories/gram for fats, 4 c/g for carbs and 4 c/g for protein.