Energy balance and its relationship to weight management.

    OCR
    GCSE

    Candidates must demonstrate a sophisticated understanding of the principle of energy balance: the equilibrium between energy intake (kilocalories/kilojoules) and energy expenditure. Mastery of this topic requires detailed knowledge of Basal Metabolic Rate (BMR) and Physical Activity Level (PAL), alongside the physiological consequences of positive and negative energy states. Responses must link energy requirements to specific life stages, distinguishing clearly between the metabolic needs of infants, adolescents, adults, and the elderly. High-level responses will evaluate the correlation between sustained positive energy balance and diet-related pathologies, specifically obesity, Type 2 diabetes, and cardiovascular disease.

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    Objectives
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    Exam Tips
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    Pitfalls
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    Key Terms
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    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award marks for explicit definition of Energy Balance as the equilibrium between energy intake and energy expenditure (BMR + PAL).
    • Credit application of knowledge where candidates calculate energy requirements based on age, gender, and activity levels.
    • Candidates must link excess energy intake specifically to the storage of adipose tissue and subsequent risk of Type 2 diabetes or CHD.
    • Reward analysis of nutritional data that identifies specific sources of excess energy (e.g., free sugars, saturated fats) rather than generic 'unhealthy food'.

    Marking Points

    Key points examiners look for in your answers

    • Award marks for explicit definition of Energy Balance as the equilibrium between energy intake and energy expenditure (BMR + PAL).
    • Credit application of knowledge where candidates calculate energy requirements based on age, gender, and activity levels.
    • Candidates must link excess energy intake specifically to the storage of adipose tissue and subsequent risk of Type 2 diabetes or CHD.
    • Reward analysis of nutritional data that identifies specific sources of excess energy (e.g., free sugars, saturated fats) rather than generic 'unhealthy food'.

    Examiner Tips

    Expert advice for maximising your marks

    • 💡When discussing weight gain, explicitly mention the conversion of excess glucose/fatty acids into adipose tissue.
    • 💡Memorise the Atwater factors: Fat (9kcal/g), Protein (4kcal/g), Carbohydrate (4kcal/g), and Alcohol (7kcal/g) for calculation questions.
    • 💡In 'Assess' questions, weigh dietary changes against lifestyle changes (increasing PAL) for a balanced argument.
    • 💡Use the term 'energy dense' for foods high in fat/sugar and 'nutrient dense' for fruits/vegetables to demonstrate vocabulary precision.

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Confusing Basal Metabolic Rate (BMR) with Body Mass Index (BMI) or using them interchangeably.
    • Stating that 'fat makes you fat' without referencing the calorific density (9kcal/g) compared to other macronutrients.
    • Providing generic advice like 'eat less' without specifying reduction in portion size or specific nutrient groups.
    • Ignoring the impact of age and gender on BMR when assessing dietary needs.

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    Comprehensive revision notes & examples

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    Key Terminology

    Essential terms to know

    Likely Command Words

    How questions on this topic are typically asked

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