I made a 272-mile hike through the Sawtooth Mountains and this was my diet (which worked well for me):
2-3 oatmeal packets in the morning
trail mix as a snack
top romanramen with powdered chili for lunch
then rice or mashed potatoes with a few seasonings mixed in for flavor such as garlic, herb, butter, cinnamon etc...
Rice, mashed potatoes, dehydrated milk, and oatmeal are the lightest foods you can bring.
Brown rice is healthier thenthan white as well.
I had to carry all my food in because there was no re-supply but I used a filter water straw for all my water needs (worked great).
Cliff bars and Snickers or M&Ms both make a great snack but are weight if you are worried about it.