Chronic Disease Prevention and Management
Domain 6 tests medical nutrition therapy (MNT) for the conditions that fill most caseloads: type 2 diabetes and prediabetes, hypertension and dyslipidaemia, obesity, chronic kidney disease, and bone health.
Diabetes and prediabetes
MNT lowers HbA1c by roughly 1% in newly diagnosed type 2 diabetes. A common target is HbA1c <7%, individualised upward for limited life expectancy or hypoglycaemia risk and lower (e.g. <6.5%) if achievable safely. The Diabetes Prevention Program: 7% weight loss plus 150 min/week of moderate activity cut progression from prediabetes to diabetes by ~58% - more than metformin. Carbohydrate consistency, counting, or exchange lists all work when they match the patient's numeracy and routine; 150 min/week of activity plus resistance training twice weekly is standard.
Hypertension
DASH plus sodium reduction: <2,300 mg/day for most adults, with 1,500 mg an aspirational target for many with hypertension. Weight loss of about 1 kg yields roughly 1 mmHg; limiting alcohol and increasing potassium-rich foods (unless contraindicated in CKD) add benefit.
Dyslipidaemia and cardiovascular risk
Saturated fat <10% of energy, with a lower target in high-risk patients, replaced by unsaturated fat; avoid trans fat; 5–10 g/day soluble fibre lowers LDL modestly; plant sterols/stanols ~2 g/day also lower LDL. Dietary change complements, and does not replace, indicated statin therapy.
Obesity and CKD
A 500–750 kcal/day deficit supports ~0.5–1 kg/week; 5–10% loss improves glycaemia, blood pressure, and lipids. CKD not on dialysis: protein 0.6–0.8 g/kg, sodium <2 g/day, potassium and phosphorus individualised to labs; dialysis raises protein needs to about 1.0–1.2 g/kg because of losses.
Worked example
A 58-year-old with BMI 32, HbA1c 7.4%, BP 142/88. Rather than a rigid "diabetic diet": a 7% weight loss (≈6 kg) plus 150 min/week activity targets both glycaemia and BP; sodium <2,300 mg and a DASH pattern address BP; recheck A1c at 3 months and refer for pharmacotherapy review if not at goal. Each recommendation is tied to a measurable outcome and a timeframe.
Traps
Applying one HbA1c target to everyone; advising very-low-carbohydrate diets without checking medications and renal function; telling patients to avoid all fats; forgetting that sodium restriction plus DASH outperforms either alone; restricting potassium in every CKD patient regardless of labs.