The essentials
Clinical nutrition deals with the role of food and nutrients in preventing and treating disease. Diet therapy means modifying a normal balanced diet to meet the needs of a sick person. A therapeutic diet is planned by a dietitian, who assesses the patient's nutritional status, plans the diet, counsels the patient and family, and monitors progress.
A normal diet can be modified in consistency (clear fluid, full fluid, soft, regular), energy and nutrients (high or low calorie, protein, fat, sodium, fibre), frequency of meals (small frequent feeds), and mode of feeding. When a patient cannot eat by mouth, feeding can be through a tube into the stomach (enteral feeding) or directly into a vein (parenteral feeding).
Key points
- Diabetes mellitus: control total carbohydrate, prefer complex carbohydrates and high-fibre foods, avoid simple sugars, regular meal timings.
- Hypertension: restrict sodium (salt, pickles, papad, processed foods).
- Fever and infections: high energy, high protein, plenty of fluids.
- Peptic ulcer: bland, non-irritating diet; small frequent meals.
- Coeliac disease: gluten-free diet — avoid wheat, barley and rye.
- Lactose intolerance: limit milk; curd is usually better tolerated.
- Obesity: energy-restricted diet with adequate protein and fibre, plus activity.
- BMI = weight (kg) ÷ height (m)². Normal adult range (WHO) 18.5–24.9; 25–29.9 overweight; 30 and above obese.
- Energy values: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g.
Exam tips
Practise BMI and energy calculations. Link each disease with the single most important modification.
Common mistakes
Confusing enteral (through the gut) with parenteral (into a vein) feeding.