... half or more. My primary diet was rice, some kind of protein, frozen veggies (usually I'd stir fry them with the meat), and ramen (generally pan fried with meat or served with rice).
Primary meats were ground beef, ground pork, and cheap packs of hot dog style sausages.
If you're worried about nutrition buy a Costco multivitamin, but I did quite well on that cheap little diet. Also keep in mind this was for all non-mission-provided expenses, but I still saved a bunch (used it to buy nice suits and ties). This was in Minnesota.