Black beans are lower in carbohydrates compared to pinto beans, making them a better choice for those following a low-carb diet for weight loss. A half-cup serving of cooked black beans contains 20 grams of carbohydrates, while a half-cup serving of cooked pinto beans contains 23 grams of carbohydrates. Therefore, if you are following a low-carb diet, black beans are a better option.