If you stay in tent you need to bring all the food you need. Norwegians would typically bring bread for breakfast and lunch, or alternatively oatmeal for breakfast. As there is no fridge you should bring food that can be stored in a tent, such as salami, rice, pasta and pre-cocked meat. Some also prefer to keep it simple, eating dried meals where you only add warm water (like Drytech that are available in most Norwegian sport shops). And please remember that you eat more while in activity so bring enough. There are unfortunately no shops nearby for supply, but possible to order newly baked bread from nearby Sognefjellshytta to be picked up the next day.
If you stay at the hotel, all food is included. Bring a thermos if you want to take warm drinks for lunch. You will prepare your own lunch at the breakfast buffet.