During ketosis, the body uses ketone bodies in the blood as opposed to blood glucose. The diet has had proven health benefits for people with certain conditions such as epilepsy. It's about total carbohydrate intake and how you choose to "spend" your carbs. Generally, you should stay under grams of carbohydrates per day. "The exact amount needed to achieve ketosis can vary on the individual, though, with carb prescriptions ranging from 10 to 60 grams per day. This total is for net carbohydrates ," says Stone.