Basic and Applied Sciences
Basic and Applied Sciences
This domain tests whether you can explain digestion, absorption, macronutrient roles, energy balance, and the components of energy expenditure accurately enough to set safe nutrition targets. The exam favors applied understanding: why protein needs rise with activity, why weight change is not linear, and when a client needs referral rather than another meal plan.
Core rules
- Digestion begins in the mouth; most absorption occurs in the small intestine. Fiber, fluids, and gut health affect tolerance and satiety.
- Energy balance is intake versus expenditure over time. Weight change of about 0.25-0.5 kg per week is a common sustainable target.
- TDEE = RMR + TEF + NEAT + EAT. RMR is usually the largest component; TEF is roughly 10% of intake; NEAT varies widely with daily movement.
- AMDRs are broad guides: carbohydrate 45-65%, fat 20-35%, protein 10-35% of calories. Active adults often need 1.2-2.0 g/kg protein.
Worked example
A lightly active 80 kg client has an estimated RMR of 1,700 kcal, activity of 500 kcal, and TEF of 200 kcal, so TDEE is near 2,400 kcal. For a modest deficit, set 1,900-2,100 kcal. At 1.6 g/kg, protein is 128 g (512 kcal); fat at 25% is 600 kcal (67 g); carbohydrate fills the remainder. Recheck hunger, adherence, and weight trend after 2-3 weeks before changing targets.
Traps
Do not treat RMR as TDEE or apply a 2,000-kcal default to everyone. Do not use AMDRs as rigid prescriptions. Do not promise rapid loss or manage disease-related diets independently; refer red flags such as disordered eating, uncontrolled diabetes, or kidney disease.