Metabolism USMLE Step 1 Practice Question

A neonate who initially appears healthy develops vomiting, diarrhea, abdominal pain, and hypoglycemia when weaning is attempted. Other features include a generalized metabolic disturbance with lactic acidosis, hyperuricemia, and hyperphosphatemia. Hereditary fructose intolerance is confirmed in the neonate through the use of an IV fructose tolerance test, and strict dietary restriction of fructose is ordered to prevent the long-term complications of the condition. In addition to fructose, dietary intake of which of the following substances should also be restricted?