"There is now a huge variety of instant dried food available. Take advantage of it. Up to four or five days food should not be too hard to plan. Beyond that, requires care and focus to keep the weight down. As a guide to use, most people will be OK with about 700 gms per person per day, dry weight. This can be broken down approximately as follows:
"Breakfasts, about 150 gms, lunches, about 150 gms and dinners about 200 gms. Ready to eat snack material, scoggin etc, about 150 gms, and hot and cold drink material, about 50 gms.
"These figures can be varied according to individual preferences, but remember that people burn 3000 to 7000 calories per day in the hills and that energy is only derived from food. Weight watching food simply wastes space. Try to keep a balance between sweet and savory items, and a balance between carbohydrate, fat, sugar, protein, vitamins and minerals. Take a variety of what you like. For shorter trips of two to four days, be more lenient on yourself, and indulge in a bit of fresh fruit and vegetables, though the bulk may remain dried. Pack food in plastic bags or containers."
The above advice comes from Geoff Spearpoint who has kindly let us reproduce it from his guidebook Moir's Guide North. The introduction to Geoff's guidebook is well worth a read; it provides excellent down-to-earth advice on preparing for tramping trips.