In an expedition situation it's vital that main meals are both good to eat and also provide plenty of calories. A tasty, hot, satisfying meal definitely makes you feel better after a hard day's activity. It's worth remembering that on expeditions your taste buds may not be so senstitive as at home, so choosing well-flavoured meals is a good idea. This is especially the case at higher altitudes.
The longer your trip the more variety you will need: eating the same meal every few days for weeks on end is going to get rather boring! We have over 40 main meals, including a good choice for vegetarians, so you should be able to live happily on our dinners for an extended period.
I like to vary the carbohydrate base of my meals from day to day. The main options are pasta (including noodles), rice and potato. Mashed potato-based meals can be very comforting, even though they may not look so attractive, provide useful flavour and are reasonable in terms of calories per gramme carried. Pasta is versatile and has some flavour of its own; its star feature is undoubtedly that it provides lots of calories for its weight. Rice needs good flavours in the sauce or accompaniment and is lower in terms of calories per gramme than pasta.
Although many meals use chicken or beef for their main protein content, it's worth including some fish meals and vegetarian meals (even if you are a card-carrying carnivore) for the sake of variety.
On longer trips especially, it can be very helpful to carry some extra bits and pieces to improve your meal or add variety. Freeze-dried herbs and spices can add useful flavour, and pine nuts are great for taste and extra calories. Salami is a good addition also. Try a few things and see what tickles your taste buds.