Nutrition, Diet and Personal Hygiene
This domain covers what the body needs, what happens when a nutrient is missing, and the daily habits that prevent infection. Expect classification of nutrients, deficiency diseases, energy values and BMI calculations.
Nutrients and energy values
- Carbohydrates – 4 kcal/g; the main energy source, roughly 55–60 % of a balanced diet.
- Proteins – 4 kcal/g; growth, repair and enzymes, roughly 10–15 %.
- Fats – 9 kcal/g; concentrated energy and carriers of fat-soluble vitamins, roughly 20–30 %.
- Vitamins, minerals, fibre and water complete a balanced diet built from cereals, pulses, milk, fruits and vegetables, and fats and sugars.
Deficiency diseases
Vitamin A – night blindness; vitamin B1 – beriberi; vitamin C – scurvy; vitamin D – rickets; iron – anaemia; iodine – goitre; calcium – weak bones.
BMI
BMI = weight in kg ÷ (height in m)². Below 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, 30 and above obese.
Personal hygiene
Daily bath, teeth brushed twice daily, short clean nails, washed uniform and socks, boiled or filtered water, handwashing before meals and after the toilet, and menstrual hygiene with changed absorbent and safe disposal.
Worked example
A 15-year-old weighs 52 kg and is 1.55 m tall. Height² = 1.55 × 1.55 = 2.4025. BMI = 52 ÷ 2.4025 = 21.6, which is in the normal range. Her diet, however, is mostly fried snacks and cola, so the advice is about diet quality – more iron-rich greens, pulses and fruit – not weight loss.
Traps that cost marks
- Using 9 kcal/g for protein or carbohydrate.
- Mixing up scurvy (vitamin C) and rickets (vitamin D).
- Claiming BMI directly measures body fat.
- Advising that all fat be removed from the diet.