Unit5 : Sports & Nutrition CBSE CLASS 12

 Unit5 : Sports & Nutrition

1. Concept of balanced diet andnutrition

2. Macro and Micro Nutrients:Food sources &functions

3. Nutritive &Non-Nutritive Components of Diet

4. Eating forWeight control – A Healthy Weight, The Pitfalls of Dieting, Food Intolerance,and Food Myths

5. Importance of Diet in Sports-Pre, Duringand Post competition Requirements

1. Concept of Balanced Diet and Nutrition

Nutrition is defined as the science of food and the study of the processes that include everything happening to food from the time it is eaten until it is utilized for various bodily functions. This involves the ingestion, digestion, absorption, utilization, and assimilation of nutrients. Nutrients are the chemical substances in food that the body requires for energy, growth, and maintenance,.

A balanced diet is one that contains different types of foods in such quantities and proportions that the body's need for calories, minerals, vitamins, and other nutrients is adequately met. It also makes a small provision for extra nutrients to withstand periods of leanness, when adequate food might not be consumed. To achieve this balance, daily meals should incorporate items from three main functional food groups:

1. Energy giving foods: These are rich in carbohydrates and fats, such as cereals, roots, tubers, sugars, jaggery, and oils.
2. Body building group: These are foods rich in proteins, including milk, meat, poultry, fish, eggs, pulses, and nuts,.
3. Protective or regulatory foods: These provide essential vitamins and minerals, and primarily consist of green leafy vegetables, yellow and orange fruits and vegetables, and citrus fruits.

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2. Macro and Micro Nutrients: Food Sources & Functions

Nutrients are broadly classified into macronutrients and micronutrients based on the daily amounts required by the body.

I. Macronutrients

These nutrients are required by the body in relatively large amounts and form the main bulk of the diet.

• Carbohydrates: They are the body's major source of energy, providing 4 kcal per gram,. They serve as the main fuel for the nervous system, brain, and red blood cells, spare proteins for tissue building, and enable proper utilization of fats. Additionally, dietary fibre (roughage) provides a feeling of fullness, aids in smooth stool elimination, and helps prevent diseases like cancer, diabetes, and heart disease.
  • Sources: Fruits, cereal grains, rice, root vegetables, pasta, breads, sugar, and whole pulses,.
• Proteins: Made of complex chains of amino acids, proteins build and repair body cells and tissues,. They form vital parts of enzymes, hormones, and antibodies, and can also provide energy (4 kcal/g) if required.
  • Sources: Milk and milk products, fish, eggs, poultry, meat, legumes, and grains.
• Fats (Lipids): Fats are the most concentrated energy source, providing 9 kcal/g. They transport fat-soluble vitamins (A, D, E, K) and are structural components of cell membranes, nerve membranes, hormones, and bile.
  • Sources: Visible fats like vegetable oils, desi ghee, butter, and margarine, as well as invisible fats found in cheese, meat, poultry, fish, milk, nuts, and seeds.
• Water: Although it provides no energy, water is a vital macronutrient that makes up to 60% of total body weight,. It regulates body temperature, acts as a universal solvent, serves as a lubricant for joints, and is the medium for all body fluids.
  • Sources: Drinking water, beverages (tea, coffee, juices), and invisible water within fruits and vegetables.

II. Micronutrients

These are required in smaller quantities but are equally essential for maintaining health and proper bodily functions.

• Vitamins: These act as "helpers" for metabolic processes.
  • Water-soluble vitamins (B-complex and C): B-vitamins are crucial for energy metabolism, nerve function, forming DNA/RNA, and making red blood cells,. Vitamin C functions as an antioxidant, aids in collagen formation for wound healing, supports the immune system, and assists in iron absorption.
    • Sources: Whole-grain cereals, pulses, meat, milk, citrus fruits, fresh cabbage, amla, and guava,,.
  • Fat-soluble vitamins (A, D, E, K): Vitamin A is needed for vision in dim light and skin health; Vitamin D regulates the absorption and deposition of calcium and phosphorus in bones; Vitamin E acts as an antioxidant protecting cell walls; and Vitamin K is necessary for proper blood clotting,,.
    • Sources: Liver, egg yolks, milk, dark green leafy vegetables, yellow/orange fruits, polyunsaturated plant oils, and exposure to sunlight (for Vitamin D),,.
• Minerals: Inorganic elements required for various physiological functions.
• Macro-minerals: Required in larger amounts, these include Sodium, Chloride, Potassium, Calcium, Phosphorus, Magnesium, and Sulphur,,,. They are essential for proper fluid balance, nerve transmission, muscle contraction, and maintaining healthy bones and teeth,,.
  • Sources: Table salt, milk and milk products, meat, fresh fruits, vegetables, whole grains, nuts, and seeds,,.
• Trace minerals (Micro-minerals): Needed in tiny amounts, including Iron, Zinc, Iodine, Selenium, and Copper,,,. Iron is a vital component of haemoglobin that carries oxygen to every cell; Iodine helps regulate thyroid hormones for growth and metabolism; and Zinc is essential for the immune system, wound healing, and protein synthesis,.
• Sources: Organ meats, red meats, dark green leafy vegetables, whole pulses, seafood, and iodized salt,.

3. Nutritive & Non-Nutritive Components of Diet

Nutritive Components Nutritive components are the chemical substances in food that the body digests, absorbs, and utilizes for physiological functions, growth, and development. These include macronutrients like carbohydrates, proteins, and fats, which provide energy and build tissues, as well as micronutrients like vitamins and minerals.

Non-Nutritive Components These are chemical compounds in foods that have no specific nutritional function, though some are added to make food smell better, taste better, or last longer. They are divided into two main categories:

1. Non-Nutritive Factors that Interfere with Nutrient Absorption (Anti-Nutritional Factors):

• Phytates: Found in unrefined cereals and millets; they bind iron, zinc, calcium, and magnesium, making them unavailable for digestion.
• Tannins: Present in legumes, tea, and turmeric; they interfere with the absorption of iron and protein.
• Trypsin Inhibitors: Found in soybeans and duck egg whites; they interfere with the digestibility of dietary proteins.
• Oxalates: Present in green leafy vegetables; they interfere with calcium absorption.
• Goitrogens: Found in cabbage, cauliflower, and peanuts; they interfere with iodine uptake by the thyroid gland.

2. Beneficial Non-Nutritive Factors:

• Phytochemicals: Compounds found in fruits and vegetables that act as antioxidants to protect cells from damage and reduce the risk of cancer.
• Anthocyanins: Give dark colors to berries and grapes and possess anti-inflammatory and anti-tumour properties.
• Flavonoids/Isoflavones: Found in soybeans and chickpeas; they act like estrogen and help lower the risk of osteoporosis and heart disease.
• Artificial Sweeteners & Preservatives: Used to duplicate sugar taste with fewer calories and to inhibit microbial growth to prolong shelf life.
• Spices and Coffee: Spices are used for flavoring or medicinal purposes, while coffee provides a stimulating effect due to caffeine.

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4. Eating for Weight Control

A Healthy Weight Maintaining a healthy weight lowers the likelihood of developing life-threatening conditions like heart disease, stroke, and Type 2 diabetes. Healthy weight is commonly assessed using the Body Mass Index (BMI), the Waist-to-Hip Ratio (WHR), or by calculating the total body fat percentage.

Eating for Weight Control Maintaining weight is a balancing act between the calories consumed and the calories burned. For healthy weight loss, the goal should be a reduction of 500g to 1 kg per week, achieved by establishing a negative energy balance of 500-1000 kcal. Effective dietary modifications include:

• Eating high-fibre foods (whole fruits, salads, beans, and whole grains) because they take longer to digest and keep you full.
• Switching to low-fat proteins (egg whites, fish, lean meats) and fat-free or low-fat milk.
• Baking or grilling foods instead of frying them to reduce calorie counts.
• Serving smaller portions using smaller plates and bowls, and cooking meals at home to control added sodium, fat, and sugar.
• Avoiding soft drinks, high-calorie snacks, and high-salt foods (which induce water retention).
• Eating frequently throughout the day (3 small meals and 2-3 snacks) to keep the metabolism stimulated, as skipping meals can decrease metabolism and lead to overeating later.

The Pitfalls of Dieting Drastic calorie reduction causes the body to go into "starvation mode," severely slowing down metabolic processes to conserve energy, which ultimately stops weight loss. Fad diets that restrict entire food groups are impractical, unhealthy, and can lead to nutrient deficiencies. Once normal eating resumes, the lost weight quickly returns. Extreme food restriction and fear of weight gain can also develop into clinical eating disorders like Anorexia nervosa.

Food Intolerance Food intolerance is a non-allergic hypersensitivity characterized by difficulty digesting certain foods. Symptoms take longer to emerge than allergies and can include stomach-ache, bloating, nausea, and migraines. Types of food intolerance include:

• Absence of an enzyme: For example, lactose intolerance occurs when the body lacks enough lactase to break down milk sugar.
• Chemical causes: Sensitivities to amines in cheese or caffeine in coffee and tea.
• Gluten intolerance: Digestive problems caused by the protein found in wheat, barley, and rye.
• Salicylate intolerance: Reactions to salicylates, which occur naturally in most plant-sourced foods like fruits and vegetables.
• Food additives: Reactions to nitrates in processed meats (causing skin rashes), MSG (causing headaches), and certain artificial colorings.

Food Myths Common misconceptions regarding diet include:

• "The fewer the carbohydrates, healthier you are": While refined carbohydrates should be avoided, eating healthy complex carbohydrates like whole grains is associated with a decreased risk of chronic diseases.
• "Oils/Margarine have fewer calories than Ghee/butter": They actually have about the same amount of calories, and some margarines are unhealthier because they contain harmful trans-fats.
• "Apples and brinjals are rich in iron because they turn brown": The browning is merely an enzymatic reaction. These foods are excellent sources of fiber, but not iron.
• "Milk should be avoided after eating fish": It is a myth that combining these causes skin diseases like leukoderma.
• "Drinking water in between meals affects digestion": Drinking water does not harm digestion; it fills the stomach so you tend to eat less, making it helpful for weight loss.

Importance of Diet in Sports Nutrition is a crucial aspect of sports training and performance. The right nutritional composition in pre-competition, during, and post-competition meals can significantly improve performance, delay fatigue, and speed up recovery. Because sports place greater physical demands on athletes, the body needs proper nutrition to repair and recover; otherwise, performance outcomes and post-training recovery suffer. A well-planned diet also helps athletes achieve specific body composition and weight goals required for their sport, prevents performance-impairing dehydration, and enhances overall physiological adaptations during training.

Pre-Competition Requirements The primary goals before an event are fuelling up glycogen stores to obtain energy and ensuring proper hydration. This controls hunger, weakness, and light-headedness while ensuring a comfortable gastrointestinal state.

• Athletes should consume a meal comprising high-carbohydrate, moderate protein, low fibre, and low-fat foods (providing 500-1000 kcal) about 2 to 4 hours before the exercise.
• If eating within two hours of the event, meals should be smaller and semi-solid or liquid.
• High-sugar foods must be avoided because they can trigger an insulin rush that leads to early fatigue, cramping, and dehydration.
• Foods should be familiar and easily digestible; heavy, fried, or high-fibre foods should be avoided just prior to the competition.
• High protein intake should be avoided before events as proteins are digested slowly and can cause dehydration by increasing water excretion.
• To maintain optimal hydration, athletes should drink 150-250 ml of water every 15 minutes and ensure sufficient fluid intake an hour before the event.

During Competition Requirements The main aim during training or competition is to maintain water balance, control body temperature, sustain normal blood sugar levels, and delay fatigue.

• Water lost through sweating must be replaced, as even slight dehydration causes physical and mental fatigue.
• During short breaks, athletes should consume carbohydrate-rich foods like bananas, juices, or carbohydrate-based drinks (less than 2% concentration), while avoiding carbonated, fizzy, and caffeinated beverages.
• If the exercise lasts for more than 60 minutes, carbohydrate-electrolyte beverages (with 5% to 8% carbohydrates) should be consumed. For endurance events lasting over two hours, carbohydrate-rich solid or liquid meals are recommended.

Post-Competition Requirements After training or competition, the body must recover to its best state to reduce the chance of injury and be ready to train the next day. The main emphasis during the recovery phase is to replace lost fluids, refill carbohydrate stores (muscle and liver glycogen), and replace electrolytes like sodium, potassium, and chloride.

• Re-hydration should begin during the exercise and continue afterward. Athletes should drink more fluid than what was lost until their body weight returns to pre-exercise levels or their urine is clear and pale.
• Immediately after the event, athletes must refuel with carbohydrates such as juice, fruit, sweet curd, or cereal to quickly replace glycogen energy stores in the muscles.
• A balanced meal containing both carbohydrates and good quality protein should be eaten within two hours after the event ends.