Medical Nutrition Therapy in Acute and Chronic Disease
Core concepts
MNT is disease-specific. Know carbohydrate counting and glycemic targets in diabetes, the role of the CKD stage-based protein prescription (higher in dialysis, restricted in non-dialysis CKD), sodium and fluid restriction in heart failure, DASH and potassium in hypertension, low-FODMAP and gluten-free diets in GI disease, and post-bariatric protein and micronutrient supplementation. Understand that critical illness involves early enteral nutrition, glycemic control, and avoidance of overfeeding; that liver disease may require branched-chain amino acid-rich or late-evening snacks for cirrhosis; and that oncology nutrition balances adequate intake against cachexia. Recognize refeeding syndrome risk (low BMI, minimal intake, electrolyte depletion) and its management: start low, go slow, and replete thiamine, phosphate, potassium, and magnesium.
Traps
Questions often test whether you know that protein restriction is not appropriate in dialysis, or that a low-sodium diet is not the same as fluid restriction. Watch for confusing DASH with a low-potassium renal diet.
Worked example
A patient with cirrhosis and ascites: sodium restriction (~2 g/day) and adequate protein (~1.2-1.5 g/kg) are indicated; protein should not be restricted despite encephalopathy unless other measures fail. Rule of thumb: in cirrhosis, feed the patient, restrict the salt.
Rule of thumb
Start enteral feeding at 10-20 kcal/kg/day in high refeeding-risk patients and advance slowly while monitoring electrolytes.