Brown beef and turkey, simmer with diced onion. Drain. Shred cabbage and set aside. Mix meat, water(depending on how soupy ypu want it), and pepper. Mix well. Add tomatoes, spinach, shredded cabbage, and carrots. Cover and simmer about 1 hour, or until cabbage is tender. Stir together lemon juice and brown sugar. Add to main mixture. Serve.