Principles of nutrition — Eduqas GCSE Food Preparation and Nutrition

Principles of nutrition is the foundation of Food Preparation and Nutrition, exploring how the body uses nutrients from food to function, grow, and repair. This topic covers macronutrients (carbohydrates, proteins, fats) and micronutrients (vitamins and minerals), their sources, functions, and the consequences of deficiency or excess. Understanding nutrition is essential for making informed dietary choices and planning balanced meals, which is a core skill in the WJEC GCSE course.

Nutrition links directly to other areas of the specification, such as food science (how cooking affects nutrient availability), food safety (storage to preserve nutrients), and dietary needs across life stages. It also underpins practical work, as students must apply nutritional knowledge when modifying recipes for health or special diets. Mastering this topic enables you to evaluate diets critically and understand public health issues like obesity and malnutrition.

In the WJEC exam, nutrition questions often appear in both written papers and the Non-Exam Assessment (NEA). You may be asked to calculate nutritional values, explain the role of specific nutrients, or justify food choices for a given scenario. A strong grasp of principles of nutrition will help you achieve high marks in analysis and evaluation questions.

• →Macronutrients: Carbohydrates (simple and complex), proteins (high and low biological value), and fats (saturated, unsaturated, and trans) – their sources, functions, and energy yields (17 kJ/g for carbs and protein, 37 kJ/g for fat).
• →Micronutrients: Vitamins (fat-soluble A, D, E, K and water-soluble B group, C) and minerals (calcium, iron, sodium, etc.) – their roles in the body and deficiency diseases (e.g., scurvy from vitamin C deficiency, anaemia from iron deficiency).
• →Dietary Reference Values (DRVs): Understanding Estimated Average Requirements (EAR), Reference Nutrient Intake (RNI), and Lower Reference Nutrient Intake (LRNI) for different age groups and genders.
• →Energy balance: The relationship between energy intake (from food) and energy expenditure (basal metabolic rate + physical activity), and consequences of imbalance (weight gain/loss).
• →Dietary guidelines: The Eatwell Guide proportions (fruit and veg, starchy carbs, proteins, dairy, oils) and current UK health recommendations (e.g., <70g fat/day, <20g saturated fat, <6g salt).

• Understanding of heat transfer: conduction, convection, and radiation.
• Knowledge of functional and chemical properties of ingredients: gelatinisation, dextrinisation, shortening, aeration, plasticity, emulsification, coagulation, foam formation, gluten formation, denaturation, enzymic browning, and oxidisation.
• Ability to explain why food is cooked: digestion, taste, texture, appearance, and safety.
• Understanding of microbiological food safety: storage, date-marks, growth conditions of bacteria/mould/yeast, and cross-contamination prevention.
• Knowledge of food preservation methods: jam making, pickling, freezing, bottling, vacuum packing.
• Ability to remedy failed results (e.g., lumpy sauce, sunken cake).
• Understanding of the positive use of microorganisms in food production (e.g., cheese, yoghurt, fermentation).

• 💡Use specific scientific terminology (e.g., gelatinisation, denaturation) in all responses.
• 💡When discussing cooking methods, always link the method to the desired sensory or nutritional outcome.
• 💡Ensure you can explain the 'why' behind food safety rules, not just the 'what'.
• 💡Practice drawing links between the chemical properties of ingredients and the results of practical experiments.
• 💡Use the provided stimulus material in Section A to ground your scientific explanations.
• 💡Use specific nutrient names and functions in your answers. For example, instead of 'vitamins are good for you', say 'vitamin C is needed for collagen production and wound healing, and its deficiency causes scurvy.' This shows depth of knowledge.
• 💡When discussing dietary needs for life stages, link to specific nutrients. For teenagers, mention increased calcium for bone growth and iron for increased blood volume. For elderly, mention vitamin D and calcium for bone health, and B12 for nerve function.
• 💡In NEA tasks, always justify your recipe modifications with nutritional reasoning. For example, 'I replaced butter with olive oil to reduce saturated fat and increase unsaturated fat, which supports heart health.'

• Confusing the different methods of heat transfer.
• Failing to link chemical changes (e.g., coagulation) to the specific ingredient being used.
• Inaccurate use of technical terminology regarding food science.
• Lack of detail when explaining the causes of food spoilage.
• Inability to justify why a specific cooking method was chosen to conserve nutritional value.
• Misconception: All fats are bad. Correction: Fats are essential for energy, cell membranes, and absorption of fat-soluble vitamins. Unsaturated fats (e.g., from olive oil, nuts) are beneficial, while saturated and trans fats should be limited.
• Misconception: Carbohydrates make you fat. Correction: Carbohydrates are the body's preferred energy source. Weight gain occurs from excess energy intake overall, not specifically from carbs. Complex carbs (whole grains) are healthier than simple sugars.
• Misconception: Protein is only for muscle building. Correction: Protein is needed for growth, repair of tissues, enzymes, hormones, and immune function. It's important for everyone, not just athletes.