The first and most important point to remember is that you have to carry and cook all your food.

Avoid carrying "water". Take powdered milk not fresh milk, dehy meals rather than fresh meat & vegs, dried fruit rather fresh fruit etc. Don't take whole packets - in many cases you can weigh out just enough for the trip + a little bit

Avoid carrying tins of anything - tins usually have quite a lot of liquid in the tin and you will have to carry a tin opener plus carry the empty tin back out.
Gas: Don't rely on the hut having gas cookers or that there will be a good wood stove/fireplace. Take you own small gas cooker with enough gas for the trip.
Snacks: Trampers usually stop every hour or so and snack on something like nuts/ dried fruit / chocolate so bring a supply. Lunch food should be able to be eaten on the track. You might be able to boil the billy but don't rely on it.
Water: These days most people carry a water bottle. Unless you are on the tops and you know it will be hot and that there is no water then a 1 Litre bottle is enough. You can refill it at streams as you go along.

Get some more ideas on Hut Meals and Track Food
If in doubt check with your Trip Leader !

Additional information