Heat the vegetable oil in a Dutch oven over medium heat. Add the ground beef and cook, stirring, for 3 minutes. Add the onion and continue to cook until the beef is no longer pink and the onion is translucent. Add the garlic and sauté for 1 minute longer.
Remove the stems and seeds from the bell peppers and chop them coarsely. Add them to the beef mixture and continue to cook for 2 minutes.
Add the tomatoes, tomato sauce, beef stock, sugar, salt, and pepper to the beef and vegetables. Bring the soup to a boil. Reduce the heat to the lowest setting and simmer for 25 to 30 minutes.
Meanwhile, cook the rice following the package directions.
To serve, mound the rice in the center of a wide, shallow bowl and ladle the soup around it. If desired, sprinkle with some chopped parsley leaves.