Q.What are macronutrients?

Nutrients are the chemical substances in food that the body needs for energy, growth and maintenance. The textbook divides them into two broad groups based purely on HOW MUCH of each the body needs daily — not on how important they are, since both groups are equally essential for health.

Macronutrients are needed in relatively large amounts: carbohydrates, proteins and fats (together called 'proximate principles' because they form the main bulk of the diet), plus water, which is also classed as a macronutrient because it is required in large quantity even though it provides no energy. In a typical Indian diet, these three energy-yielding macronutrients contribute to total energy intake in a fixed proportion: carbohydrates 55-60%, protein 10-15%, and fats 20-30%.

Micronutrients — vitamins and minerals — are needed only in small amounts, but a deficiency in even one of them can cause a specific disease (e.g., vitamin D deficiency affecting bone health, iron deficiency causing anaemia), which is why 'micro' refers only to the quantity required, never to their importance.

A balanced diet must supply BOTH groups: eating only energy-rich macronutrient foods while skipping fruits and vegetables (the main source of micronutrients) is just as unbalanced as the reverse. Essential nutrients, their broad sources and functions: Carbohydrates (cereals, sugar, fruits — energy, 4 kcal/g), Proteins (milk, meat, pulses, eggs — body building, 4 kcal/g), Fats (oils, ghee, nuts — concentrated energy, 9 kcal/g, transport fat-soluble vitamins), Water (fluids, fruits — temperature regulation, lubrication), Vitamins (fruits, vegetables, dairy, meat — mostly act as metabolic 'helpers'), and Minerals (dairy, meat, vegetables, salt — bone health, fluid balance, oxygen transport, enzyme function).