Macronutrients & Micronutrients
What this domain covers
The Macronutrients & Micronutrients domain tests whether you can translate food into energy and building blocks, and whether you can spot deficiencies and excesses. Expect calculations, food-source comparisons, and questions on digestion, absorption, and bioavailability.
Core rules
- Energy values: protein and carbohydrate 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g. Fiber yields about 2 kcal/g in mixed diets.
- Protein: 9 essential amino acids; complete proteins supply all in adequate amounts. General RDA is 0.8 g/kg; active adults and resistance trainees commonly need 1.2-2.0 g/kg. Leucine-rich doses of 20-40 g stimulate muscle protein synthesis.
- Fat: essential fatty acids are linoleic (omega-6) and alpha-linolenic (omega-3); aim for 20-35% of calories, saturated fat under 10%, and added sugar under 10%.
- Carbohydrate: AMDR 45-65%; fiber 25-38 g/day. Water-soluble vitamins (B, C) are not stored appreciably; fat-soluble vitamins (A, D, E, K) are.
- Bioavailability: heme iron absorbs better than non-heme; vitamin C enhances non-heme iron, while phytates, oxalates, calcium, and tannins inhibit it.
Worked example
A 2,000-kcal plan at 30% protein, 30% fat, 40% carbohydrate: protein 2000×0.30÷4 = 150 g; fat 2000×0.30÷9 ≈ 67 g; carbohydrate 2000×0.40÷4 = 200 g. Check: 150×4 + 67×9 + 200×4 = 600 + 603 + 800 = 2,003 kcal, so rounding explains the small gap.
Traps
Using 4 kcal/g for fat, calling a food "complete" just because it contains protein, treating percentage targets as more important than grams, and forgetting that fat-soluble vitamins can reach toxic intakes. Plant proteins are not automatically incomplete; combinations across the day matter more than a single meal.