Answer: Sour cream is keto-friendly as long as you avoid low-fat varieties.
Sour cream is a good keto-friendly dairy option. One serving (2 tbsp) of sour cream only contains about 1 g of net carbs, and is high in fat.
Stick with full-fat sour creams. Avoid varieties that advertise themselves as low-fat, as these usually add sugar or other carbs to compensate.