Food — Sources, Balanced Diet and Food Preservation

Overview

Food is a foundational topic in Environmental Studies for HP TET, connecting everyday experiences of children to scientific concepts about nutrition, health and the environment. Questions from this area test factual recall (nutrients, sources, preservation methods) as well as application-based understanding (identifying balanced meals, linking food habits to health outcomes).

For the exam, you must know the classification of food sources (plant vs animal, local vs processed), the components of a balanced diet with their functions, and traditional as well as modern food preservation techniques. Himachal Pradesh's unique food culture — apples, millets, dried fruits and fermented foods — often appears in context-based questions. Mastering this topic also helps in pedagogy questions where EVS integration with health education is tested.

Key Concepts

• **Sources of food are broadly plant-based and animal-based.** Plants give us cereals, pulses, vegetables, fruits, oils and spices. Animals provide milk, eggs, meat, fish and honey.

• **Food contains six essential nutrients:** Carbohydrates, proteins, fats, vitamins, minerals and water. Each performs distinct body functions — energy, growth, protection and regulation.

• **A balanced diet provides all nutrients in correct proportions** suited to age, activity level and physiological condition (pregnancy, illness). It is not about expensive food but about variety and adequacy.

• **Energy-giving foods** (carbohydrates and fats) act as fuel. **Body-building foods** (proteins) support growth and repair. **Protective foods** (vitamins and minerals) guard against disease.

• **Deficiency diseases arise from prolonged lack of specific nutrients** — night blindness (Vitamin A), scurvy (Vitamin C), rickets (Vitamin D), anaemia (iron), goitre (iodine).

• **Food preservation prevents spoilage** caused by microorganisms, enzymes and oxidation. Methods include drying, refrigeration, salting, pickling, canning and pasteurisation.

• **Traditional preservation in Himachal Pradesh** reflects local climate — sun-drying apples and apricots, making siddu with stored wheat, fermenting chhang from barley, and preparing pickles with mustard oil and spices.

• **Food safety and hygiene** — washing hands, covering food, using clean water, avoiding stale food — are essential life-skill concepts for primary EVS.

Formulas / Key Facts

| Nutrient | Chief Sources | Main Function | Deficiency Disease | |----------|---------------|---------------|-------------------| | Carbohydrates | Rice, wheat, potato, sugar | Energy | General weakness | | Proteins | Pulses, milk, eggs, fish, soybean | Growth and repair | Kwashiorkor, Marasmus | | Fats | Ghee, butter, oil, nuts | Energy reserve, insulation | Poor growth, dry skin | | Vitamin A | Carrot, papaya, milk, liver | Vision, skin health | Night blindness | | Vitamin B complex | Whole grains, eggs, green vegetables | Metabolism, nerve function | Beriberi, pellagra | | Vitamin C | Amla, orange, lemon, guava | Immunity, wound healing | Scurvy | | Vitamin D | Sunlight, fish, egg yolk | Bone and teeth formation | Rickets (children), Osteomalacia (adults) | | Calcium | Milk, cheese, ragi, green leafy vegetables | Bone and teeth strength | Weak bones, dental problems | | Iron | Spinach, jaggery, apple, meat | Haemoglobin formation | Anaemia | | Iodine | Iodised salt, seafood | Thyroid function | Goitre |

**Preservation Methods at a Glance:**

• **Drying / Dehydration** — Removes moisture; used for fruits, fish, meat.
• **Refrigeration / Freezing** — Slows microbial growth.
• **Salting** — Draws out water; used for fish and pickles.
• **Sugar preservation** — High sugar concentration (jams, jellies) inhibits bacteria.
• **Pickling** — Acid (vinegar) or oil creates unfavourable environment for microbes.
• **Canning** — Food sealed in airtight containers after heating.
• **Pasteurisation** — Milk heated to 72°C for 15 seconds to kill pathogens.

**HP-Specific Facts:**

• Himachal is India's leading apple producer; apples are sun-dried to make "sukha seb."
• Traditional fermented drinks include chhang (barley) and lugri (rice).
• Siddu and babru are traditional HP dishes using locally grown wheat and pulses.
• Mid-Day Meal Scheme provides balanced nutrition in government schools.

Worked Examples

**Example 1 — Identifying Nutrient Deficiency**

*Question:* A child complains of bleeding gums and slow wound healing. Which nutrient is likely deficient and which food should be recommended?

*Solution:* 1. Symptoms — bleeding gums and delayed healing point to **Vitamin C deficiency (scurvy)**. 2. Recommended foods — citrus fruits (orange, lemon), amla, guava. 3. Reason — Vitamin C is essential for collagen synthesis and immunity.

**Example 2 — Classifying a Meal as Balanced**

*Question:* Evaluate this meal — rice, dal, spinach sabzi, curd, and an orange. Is it balanced?

*Solution:*

• Rice → Carbohydrates (energy)
• Dal → Proteins (body-building)
• Spinach → Iron, Vitamin A, fibre (protective)
• Curd → Calcium, proteins, probiotics
• Orange → Vitamin C (protective)

The meal covers energy, body-building and protective categories with variety. **Yes, it is a balanced meal.**

**Example 3 — Preservation Technique**

*Question:* Why do people in Kinnaur dry apricots in summer?

*Solution:* 1. Fresh apricots spoil quickly due to high water content. 2. Drying removes moisture, preventing bacterial and fungal growth. 3. Dried apricots (khubani) can be stored for months and consumed in winter when fresh fruit is unavailable. 4. This is an example of **dehydration/sun-drying** — a traditional preservation method suited to the dry mountain climate.

Common Mistakes

• **Confusing energy-giving and body-building foods.** Wrong: "Proteins give energy." Fix: Proteins primarily build and repair tissues; carbohydrates and fats are the main energy sources.

• **Mixing up fat-soluble and water-soluble vitamins.** Wrong: "Vitamin C is stored in the body like Vitamin A." Fix: Vitamins A, D, E, K are fat-soluble and stored; B and C are water-soluble and need daily intake.

• **Assuming balanced diet means expensive diet.** Wrong: "Poor families cannot have balanced meals." Fix: Locally available cereals, pulses, seasonal vegetables and milk can form a balanced diet at low cost.

• **Thinking refrigeration kills microbes.** Wrong: "Freezing destroys bacteria." Fix: Freezing only slows microbial activity; bacteria can revive when food thaws.

• **Ignoring HP-specific food culture in EVS.** Wrong: Giving only generic examples. Fix: Include regional foods — apples, millets, chhang, siddu — to align with HP TET context.

Quick Reference

• **Three food groups:** Energy-giving (carbs, fats) | Body-building (proteins) | Protective (vitamins, minerals).

• **Vitamin C sources:** Amla, citrus fruits, guava — prevents scurvy.

• **Iron + Vitamin C together** improves iron absorption — pair spinach with lemon.

• **Pasteurisation temperature:** 72°C for 15 seconds (milk).

• **HP staple preservation:** Sun-drying (apples, apricots), fermentation (chhang), oil-based pickling.

• **Mid-Day Meal Scheme** aims to provide nutrition and improve school attendance.