There is much controversy regarding what diet to recommend to sufferers of diabetes mellitus. The diet most often recommended is high in dietary fiber, especially soluble fiber, but low in fat (especially saturated fat). Recommendations of the fraction of total calories to be obtained from carbohydrate intake range from 1/6 to 75% – a 2006 review found recommendations varying from 40 to 65%. Patients may be encouraged to reduce their intake of carbohydrates that have a high glycemic index (GI), although this is also controversial. (In cases of hypoglycemia, they are advised to have food or drink that can raise blood glucose quickly, followed by a long-acting carbohydrate (such as rye bread) to prevent risk of further hypoglycemia.) But others question the usefulness of the glycemic index and recommend high-GI foods like potatoes and rice.