Balanced diet principles Revision Notes
Subject: Food Preparation and Nutrition | Level: GCSE | Exam Board: OCR
Mastering the principles of a balanced diet is crucial for success in your OCR GCSE Food Preparation and Nutrition exam. This guide breaks down the Eatwell Guide, energy balance, and key nutrients, providing you with the scientific understanding and exam technique needed to secure top marks.
Revision Notes & Key Concepts
Key Terms & Definitions
- Balanced Diet
- A diet that contains the correct proportions of carbohydrates, fats, proteins, vitamins, minerals, and water necessary to maintain good health.
- Macronutrient
- Nutrients required in large amounts in the diet, namely carbohydrates, proteins, and fats.
- Micronutrient
- Nutrients required in small amounts in the diet, namely vitamins and minerals.
- Energy Balance
- The relationship between energy intake (from food) and energy expenditure (from physical activity and bodily functions).
- Saturated Fat
- A type of fat, found primarily in animal products and some processed foods, that is solid at room temperature and can raise levels of 'bad' LDL cholesterol in the blood.
- Dietary Fibre
- A type of carbohydrate that cannot be digested by the body's enzymes. It is essential for maintaining a healthy digestive system.
Worked Examples
Worked Example
Question: A 15-year-old boy is a keen rugby player who trains three times a week. Explain how his diet should be adapted to support his active lifestyle, referring to the Eatwell Guide. (6 marks)
Solution: **Point 1 - Increased Energy**: The boy will have a higher energy expenditure due to his rugby training. Therefore, his intake of starchy carbohydrates should be increased to provide the necessary energy for his muscles. He should consume wholegrain options like wholemeal bread and brown rice, as these provide a slow, sustained release of energy. **Point 2 - Muscle Repair**: The high-intensity nature of rugby will cause micro-tears in his muscle fibres. To repair this damage and build new muscle tissue, his protein intake should be increased. Good sources would include lean chicken, fish, or beans and pulses. **Point 3 - Bone Strength & Hydration**: As a teenager, he is still building bone density. His diet should include an adequate amount of dairy or fortified alternatives to provide calcium for strong bones, which is crucial in a high-impact sport like rugby. He must also ensure he is well-hydrated by drinking plenty of water before, during, and after training to replace fluids lost through sweat.
Worked Example
Question: Analyse the nutritional content of a standard shepherd’s pie and suggest three modifications to make it healthier, justifying each change. (8 marks)
Solution: **Analysis**: A standard shepherd's pie contains ingredients from several Eatwell Guide sections. The potato topping provides starchy carbohydrates. The lamb mince provides protein and, typically, a high amount of saturated fat. The gravy and any added butter or cheese also contribute fat and salt. It may contain some vegetables like onions and carrots, but often not enough to count as one of the 5-a-day. **Modification 1**: Replace the lamb mince with extra-lean (5% fat) beef mince or lentils. **Justification 1**: This significantly reduces the saturated fat content, which is beneficial for cardiovascular health and helps to lower the risk of high cholesterol. Using lentils would also increase the dietary fibre content. **Modification 2**: Add more vegetables to the mince filling, such as peas, celery, and leeks, and serve with a side of steamed green beans. **Justification 2**: This increases the vitamin, mineral, and fibre content of the meal, helping the consumer to achieve their 5-a-day target. Fibre is important for maintaining a healthy digestive system. **Modification 3**: Replace the butter and cheese in the mashed potato topping with a small amount of olive oil spread and use sweet potatoes for half of the topping. **Justification 3**: This again reduces the saturated fat content. Using sweet potatoes alongside white potatoes increases the variety of nutrients, providing more Vitamin A and lowering the overall glycaemic index of the meal.
Practice Questions
Question: Explain the functions of protein in the diet. (4 marks)
Answer:
Question: A 65-year-old woman has been advised to reduce her risk of developing cardiovascular disease. Explain three dietary changes she could make. (6 marks)
Answer:
