Heat the oil in a large soup pot over medium heat. Add the garlic, onions, bell peppers, carrots, celery and sweet potato. Cook on high for 8 - 10 minutes, until soft.
Add turkey and cook until browned, 5 - 7 minutes, stirring often to break up into smaller pieces.
Once meat is browned, add 1½ cups water, diced tomatoes in their juices, tomato sauce, chili powder, cumin, paprika, cayenne, salt, black pepper and red pepper flakes. Bring to a boil, then reduce to medium heat.
Add beans and simmer uncovered until the chili thickens, about 45 minutes, stirring occasionally so that the chili does not stick to the pot. If the chili becomes too thick, add remaining water to reach a desirable consistency.
Toward the end of the cooking time, taste and adjust seasonings; for example, if it needs an extra kick, add more cayenne pepper.
Serve hot, with optional toppings.