Final answer:
A dietician will most closely monitor carbohydrates in a patient with diabetes, as they are broken down into glucose which must be kept within a normal range.
Step-by-step explanation:
A dietician will monitor carbohydrates most closely in a patient with diabetes. Diabetes mellitus is a metabolic disorder characterized by high blood sugar levels, primarily due to the body's inability to manage glucose efficiently. For individuals with diabetes, monitoring carbohydrate intake is crucial because carbohydrates are broken down into sugars such as glucose during digestion. A dietician must ensure that the patient maintains a balanced diet that keeps blood glucose levels within a normal range, typically through dietary adjustments, regular exercise, and sometimes medication or insulin injections.