Components of Food

Carbohydrates: give energy (rice, wheat, sugar, potato). Proteins: body building — growth and repair (dal, eggs, milk, meat). Fats: extra energy + protection (oil, butter, nuts). Vitamins: disease prevention, metabolism (fruits, vegetables). Minerals: bones, blood (calcium in milk, iron in spinach). Water: 60-70% of our body — essential for all functions.

Test for starch: add iodine solution → turns blue-black. Test for protein: add copper sulphate + sodium hydroxide → turns violet (Biuret test). Test for fat: rub on paper → leaves translucent spot. Test for sugar (glucose): add Benedict's solution, heat → turns orange-red.

Lack of nutrients causes diseases. Vitamin A deficiency → Night blindness. Vitamin C deficiency → Scurvy (bleeding gums). Vitamin D deficiency → Rickets (weak bones). Iron deficiency → Anaemia (pale skin, tiredness). Iodine deficiency → Goitre (swollen thyroid). Protein deficiency → Kwashiorkor (bloated belly in children).

A balanced diet contains ALL nutrients in right amounts. Include: cereals (carbs), pulses/meat (protein), milk/dairy (protein+calcium), fruits/vegetables (vitamins+minerals), small amount of fats. Avoid: too much sugar, too much fat, junk food. Eat variety of foods — no single food is complete!