Components of Food

Food contains vital chemical substances called Nutrients that our bodies cannot synthesize in sufficient quantities and must obtain from diet. Nutrients are grouped into three functional categories:

1. Energy-Giving Foods (Carbohydrates & Fats)

• Carbohydrates: The primary, readily accessible source of biological energy. Found as sugars (glucose, fructose, sucrose) and complex starch in wheat, rice, potatoes, maize, and bananas. When digested, carbohydrates break down into glucose, fueling cellular respiration.
• Fats (Lipids): Concentrated energy reserves that deliver more than twice the energy per gram compared to carbohydrates! Sources include butter, ghee, mustard oil, groundnuts, and cheese. Fats also insulate the body against cold temperatures and cushion internal organs.

2. Body-Building Foods (Proteins)

• Proteins are essential for cellular growth, muscle building, and tissue repair after injury. They are made of building blocks called amino acids.
• Plant Sources: Pulses (dal), chickpeas (chana), peas, soybeans, and kidney beans (rajma).
• Animal Sources: Milk, paneer, eggs, fish, and chicken.

3. Protective Foods (Vitamins & Minerals)

• Required in small (micronutrient) quantities to protect the body against infectious diseases, maintain healthy bones, teeth, gums, and support nervous function.

Scientists identify nutrients in raw or cooked food using simple chemical indicator reactions:

1. Test for Starch (Dilute Iodine Test)

• Take a small piece of food (e.g., a slice of raw potato or boiled rice).
• Add 2 to 3 drops of dilute Iodine solution.
• Observation & Inference: If the color turns Blue-Black, it confirms the presence of Starch. If it remains yellowish-brown, starch is absent.

2. Test for Protein (Copper Sulphate & Caustic Soda Test)

• Mash a small quantity of food (e.g., boiled dal or powdered pulses) with 10 drops of water in a clean test tube.
• Add 2 drops of Copper Sulphate solution (CuSO4).
• Add 10 drops of Caustic Soda solution (NaOH) and shake well.
• Observation & Inference: If the mixture turns Violet / Purple, it confirms the presence of Proteins.

3. Test for Fats (Translucent Paper Spot Test)

• Wrap a small food sample (e.g., a crushed groundnut or butter) inside a piece of paper and crush it gently without tearing the paper.
• Straighten the paper and hold it against a light source.
• Observation & Inference: An oily, translucent patch through which light passes faintly confirms the presence of Fats.

Micronutrients and facilitators keep physiological processes in balance:

• Vitamin A: Maintains healthy skin, cornea, and vision. (Sources: Carrots, papaya, mango, milk, spinach).
• Vitamin B-Complex: Essential for carbohydrate metabolism, red blood cell synthesis, and nervous health. (Sources: Whole grains, yeast, liver, milk).
• Vitamin C: Powerful antioxidant, promotes wound healing, collagen synthesis, and immune defense against infections. Destroyed easily by heat/cooking! (Sources: Amla, oranges, lemons, tomatoes, guavas).
• Vitamin D: Facilitates absorption of calcium for strong bones and teeth. Synthesized naturally in the skin when exposed to morning sunlight! (Sources: Milk, butter, fish, egg yolk).
• Dietary Fibre (Roughage): Indigestible plant cellulose that adds bulk to feces, facilitating regular peristalsis and curing constipation. (Sources: Whole wheat roti, unpolished oats, fresh fruits, raw salads).
• Water: Makes up 65-70% of human body weight. Transports nutrients and hormones, eliminates toxic wastes via urine and sweat, and regulates body temperature.

A Balanced Diet provides all essential nutrients in correct relative proportions, along with adequate roughage and clean water, matching an individual's age and physical activity level.