Warm a large stock pot over high heat and add the oil.
Add the carrots, celery and onions, and immediately reduce the heat. You want to sweat the vegetables for about 15 minutes. This means you want the heat low enough to just barely be able to hear a sizzle. You want the veggies to soften, but not brown. So stir semi-frequently.
Add the tomatoes, vegetable stock, spices and sweet potato.
Cook until the sweet potatoes are cooked through and then stir in the pinto beans.
Cook for about 2-3 minutes longer to warm the beans through.
Serve with a side of corn bread.
Please note that the nutrition data below is a ballpark figure. Exact data is not possible.