Combine ground beef, onion, garlic, and green pepper in a large saucepan. Cook and stir until meat is brown and vegetables are tender. Drain grease.
Stir diced tomatoes, tomato sauce, and tomato paste into the pan. Season with oregano, basil, salt, and pepper. Simmer spaghetti sauce for 1 hour, stirring occasionally.
Per Serving: 185 calories; 9.3 g fat; 15 g carbohydrates; 12.4 g protein; 35 mg cholesterol; 931 mg sodium