Home Science: Class 11 (Book 1) — Chapter 3: Food, Nutrition, Health and Fitness

• Food: Any solid or liquid substance which, when swallowed, digested, and assimilated, provides the body with essential nutrients and keeps it well. It is the basic necessity of life, supplying energy, enabling growth, repairing tissues, and regulating body functions.
• Nutrition: The science of foods, nutrients, and other substances they contain, and of their actions within the body (including ingestion, digestion, absorption, metabolism, and excretion). It also encompasses social, psychological, and economic dimensions.
• Nutrients: Constituents in food that must be supplied to the body in suitable amounts. They include carbohydrates, proteins, fats, minerals, vitamins, water, and fibre.

Nutrients are classified based on the quantity required by the body daily:

• Macronutrients: Required in large amounts by the body. These include Carbohydrates, Proteins, Fats, Water, and Fibre/Roughage.
• Micronutrients: Required in small amounts by the body. These include Vitamins and Minerals (such as Calcium, Iron, and Iodine).

A Balanced Diet is one which includes a variety of foods in adequate amounts and correct proportions to meet the day's requirements of all essential nutrients, while providing a safety margin or reserve to withstand short durations of deprivation.

A balanced diet ensures the following:

1. Includes a variety of food items.
2. Meets the RDA for all nutrients.
3. Includes nutrients in correct proportions.
4. Provides a safety margin for nutrients.
5. Promotes and preserves good health.
6. Maintains acceptable body weight for height.

The Recommended Dietary Allowances (RDA) are nutrient guidelines formulated keeping extra allowances in mind to cover the needs of practically all healthy individuals. The relationship between requirements and RDA is expressed as:

According to the World Health Organisation (WHO), Health is defined as "the state of complete physical, emotional, and social well-being, not merely the absence of diseases or infirmity."

• Mental Health: A state of emotional and psychological well-being in which an individual is able to use their cognitive and emotional capabilities, function in society, and meet the ordinary demands of everyday life.

Physical Fitness is the body's ability to function efficiently and effectively in work and leisure activities, to be healthy, to resist diseases, and to meet emergency situations. It is divided into five categories:

1. Aerobic fitness
2. Muscular strength
3. Muscular endurance
4. Flexibility
5. Body composition

Energy release values per gram of macronutrient:

The Food Guide Pyramid is a graphic depiction of the daily food guide illustrating variety, moderation, and proportion:

• Apex (Use Sparingly): Fats, oils, and sugars.
• Middle-Upper Tier (2-3 Servings): Milk, yogurt, meat, poultry, fish, eggs, dry beans, and nuts.
• Middle-Lower Tier (3-5 Servings): Vegetables and fruits.
• Base (6-11 Servings): Bread, cereal, rice, and pasta.

Vegetarians rely on plant foods but can achieve nutritional adequacy by selecting meat alternatives like legumes, seeds, nuts, tofu, and fortified soy milk (fortified with calcium, vitamin D, and vitamin B12).

• Irregular meals and skipping meals: Breakfast is the most frequently omitted meal, especially among girls due to the pursuit of thinness, which can slow metabolism and lead to weight gain.
• Snacking: Frequent snacking is common; it can help maintain energy levels if healthy choices are made, but relying solely on snacks is harmful.
• Fast foods: Highly popular in urban areas due to convenience and social factors, but typically high in fat, sodium, and empty calories.

• External Factors: Family unit, parenting practices, peers, social/cultural norms, mass media, fast foods, food fads, and personal experiences.
• Internal Factors: Physiological needs, body image, self-concept, personal values, food preferences, psychosocial development, and health status.

Anaemia is a global health issue primarily caused by iron deficiency. It affects women and girls disproportionately.

• According to the NFHS-3 Survey (2005-06), $56\%$ of adolescent girls and $30\%$ of adolescent boys in India are anaemic.
• Causes include poverty, inadequate diet, repetitive pregnancy, lactation, and poor access to health services.
• Interventions include iron-rich foods and iron supplementation.

• Anorexia Nervosa: A psychological eating disorder characterized by extreme obsession with thinness, severe body image distortion, and self-starvation. It can lead to delayed menstruation, permanent stature minimization, osteoporosis, and even death.
• Bulimia: An eating disorder characterized by cycles of bingeing (overeating) followed by purging (induced vomiting or laxative abuse). It can cause convulsions, renal failure, irregular heartbeats, and dental erosion.