Nutrition and Food Science
Core concepts
Candidates must be able to move fluently between nutrient classes (macronutrients: carbohydrate, protein, lipid; micronutrients: vitamins and minerals), energy yield factors (carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g), and the dietary reference intakes (Estimated Average Requirement, Recommended Dietary Allowance, Adequate Intake, Tolerable Upper Intake Level). Know digestion and absorption sites, the role of fiber and glycemic response, protein quality (complete vs. incomplete, complementary proteins, biological value), and fluid/electrolyte balance. Understand food science basics: Maillard browning, caramelization, gelatinization and retrogradation of starch, denaturation, emulsion stability, and the effect of pH and temperature on nutrient retention.
Traps in questions
The most common error is confusing a requirement with a recommendation, or treating an AI as an RDA. Watch for questions that ask which nutrient is most limiting in a vegan diet (B12, not protein) or which vitamin is destroyed by heat and light (ascorbic acid). Energy calculation questions often bury a distractor in the portion size or in alcohol calories. Read whether the stem asks for kcal per gram or per serving.
Worked example
A tray provides 60 g carbohydrate, 25 g protein, and 15 g fat. Energy = (60 x 4) + (25 x 4) + (15 x 9) = 240 + 100 + 135 = 475 kcal. Percent from fat = 135 / 475 = 28 percent. Rule of thumb: always compute each macronutrient separately first, then sum, and check that percentages total 100.