1.3.8Unit 1: Lifestyle, Transport, Genes and Health
Data on Effect of Diet — IAL Edexcel Linear Revision Notes & Topical Questions
5 min read 5 parts Lesson 26 of 29 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Part 1 of 5Diet and Disease
Saturated fat
- Saturated fat Diets high in saturated fat tend to raise LDL cholesterol,
- which is linked with a higher risk of CVD,
- although studies do not always agree.
Salt
- Salt High salt intake increases blood pressure in many people, raising the risk of damage to the artery lining.
Fibre and plants
- Fibre and plants Diets rich in fruit, vegetables and wholegrains are linked with lower CVD risk.
Public information
- Public information Food labels and traffic light systems help consumers see the fat, sugar and salt content of foods.
Part 2 of 5Measuring Obesity
Measuring Obesity
BMI
- BMI Body mass index is mass in kilograms divided by height in metres squared, expressed in kg/m².
BMI categories
- BMI categories Below 18.5 is underweight, 18.5 to 24.9 is healthy, 25 to 29.9 is overweight and 30 or more is obese.
Waist-to-hip ratio
- Waist-to-hip ratio This is the waist circumference divided by hip circumference; a high value shows fat stored around the abdomen,
- which carries a greater health risk.
Limitations
- Limitations BMI does not distinguish muscle from fat, so very muscular people may be classed as overweight.
Part 3 of 5Other Public Health Measures
1
Research on smoking led to health warnings on packets, advertising restrictions and support to help people quit.
2
Evidence that inactivity raises CVD risk has led to campaigns encouraging exercise, including more physical education in schools.
3
Data on diet and obesity has encouraged food labelling, reduced salt and sugar in products and healthy eating campaigns.
4
The effectiveness of each measure is judged by monitoring changes in the incidence of CVD over time.
5
Individual choice is influenced by cost, convenience and education, so not everyone has equal opportunity to make healthy choices.
Part 4 of 5Worked Example
Question
- A person has a mass of 70 kg and a height of 1.75 m.
- Calculate the BMI and state the category.
- BMI = mass ÷ height².
- Height² = 1.75 × 1.75 = 3.0625 m².
- BMI = 70 ÷ 3.0625 = 22.9 kg/m².
Answer The BMI is 22.9 kg/m², which is within the healthy range of 18.5 to 24.9.
Part 5 of 5Exam Checklist & Tips
1.3.8 – Key Points for the Exam
- BMI
- Body mass index;
- mass in kg divided by height in m squared.
- Body mass index;
- Waist-to-hip ratio Waist circumference divided by hip circumference.
- Obese Having a BMI of 30 kg/m² or above.
- Incidence The number of new cases of a disease in a population in a given time.
Common Mistakes
- Forgetting to square the height when calculating BMI.
- Using centimetres instead of metres for height.
- Assuming BMI is accurate for everyone, including athletes with high muscle mass.
- Stating that one study proves a link between a food and disease when others disagree.
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