Nutrition, Diet and Balanced Diet
This section covers nutrition, diet and balanced diet. The exam tests nutrient classes, energy values, deficiency diseases, balanced-diet planning and simple nutritional assessment such as BMI.
Nutrients and energy
Carbohydrate and protein supply about 4 kcal per gram; fat supplies about 9 kcal per gram. Water is a nutrient and is needed for temperature regulation and transport. Vitamins and minerals are micronutrients needed in small amounts. A balanced diet supplies energy and all nutrients in required proportions and includes cereals, pulses, vegetables, fruits, milk or alternatives, fats and safe water.
Deficiency patterns
Protein-energy malnutrition includes kwashiorkor, with oedema and protein deficiency, and marasmus, with severe wasting. Vitamin A deficiency causes night blindness; vitamin C deficiency causes scurvy; vitamin D deficiency causes rickets in children; iron deficiency causes anaemia; iodine deficiency causes goitre.
Worked example
A student weighs 60 kg and is 1.65 m tall. BMI = 60 divided by 1.65 squared = 60 divided by 2.7225 = 22.0. For adults, 18.5-24.9 is the normal range, so this value is normal. Reasoning shown: square the height first, then divide weight by that value. BMI is a screening tool, not a diagnosis.
Traps
Do not give fat 4 kcal per gram. Do not treat BMI as valid for everyone, including children, pregnant women and highly muscular athletes. Do not assume more vitamins are always better. Do not describe a balanced diet as an expensive diet.