In a medium pot or dutch oven, heat oil over medium heat. Add onion and garlic; cook, stirring frequently, for 2 to 3 minutes, or until onion is tender.
Add water, tomatoes with their juice, and lentils. Cover and simmer for 15 minutes.
Add carrots, worcestershire sauce, vinegar, and salt. Cover and simmer 25 more minutes or until lentils and vegetables are tender.
Garnish with chopped parsley (OR you can add fresh spinach and wilt it into the soup).