Fueling Your Performance: Study Notes on Food and Nutrition (Physical Education)

Hello Future Athletes and Health Enthusiasts!

Welcome to the essential chapter on Food and Nutrition. You might think PE is just about running faster or jumping higher, but what you put into your body is the absolute foundation for success. Think of your body like a high-performance sports car—you need the right fuel to win the race and keep the engine running smoothly!

In these notes, we will break down the crucial connection between diet, fitness, and recovery, ensuring you know how to eat smart to train hard. Don't worry if this seems tricky at first; we will use simple analogies to make sure every concept sticks!

I. The Essential Nutrients: The Building Blocks of Performance

Food is made up of different nutrients, each serving a unique, vital purpose. We categorize these into two main groups: Macronutrients (needed in large amounts) and Micronutrients (needed in small amounts).

Quick Trick: Macros provide energy (Calories); Micros regulate processes and protect.

A. Macronutrients (The Energy Providers)

These nutrients are measured in kilocalories (kcal) or kilojoules (kJ) and are responsible for fueling our physical activities and maintaining body structures.

  1. Carbohydrates (Carbs)

    Primary Function: The body's preferred and most efficient source of energy, especially for high-intensity activities.

    • Storage: Excess carbs are stored as glycogen in the liver and muscles. This muscle glycogen is the primary fuel tank during exercise.
    • Types:
      • Simple Carbs: Quick energy release (sugars, sweets, honey). Good for immediate boosts.
      • Complex Carbs: Slow, sustained energy release (pasta, brown rice, whole grains, potatoes). Essential for building up glycogen stores (carbohydrate loading).
    • Energy Yield: Approximately 4 kcal per gram.
  2. Fats (Lipids)

    Primary Function: Provides long-term, concentrated energy; insulation; protection of organs; transport of fat-soluble vitamins (A, D, E, K).

    • Fats are the backup fuel, primarily used during low-intensity, long-duration exercise (like slow jogging).
    • Energy Yield: Approximately 9 kcal per gram (more than double carbs or protein!).
  3. Proteins

    Primary Function: Growth, repair, and maintenance of tissues (especially muscle). Proteins are the building blocks (like bricks for a house).

    • Proteins are made up of amino acids.
    • While they can be used for energy (4 kcal/g), this usually only happens if carbohydrate and fat stores are completely depleted. We want to save protein for muscle repair!
B. Micronutrients and Water (The Regulators)

These do not provide energy (calories) but are essential for the body's chemical reactions, structure, and regulation.

  1. Vitamins

    Function: Help regulate metabolism, support energy release from food, and maintain general health.

    • Example: B vitamins are crucial for releasing energy from carbs. Vitamin C supports the immune system.
  2. Minerals

    Function: Essential for bone structure, fluid balance, and oxygen transport.

    • Example 1: Calcium is necessary for strong bones (important for impact sports).
    • Example 2: Iron is required to form haemoglobin, which transports oxygen in the blood to working muscles. Low iron leads to fatigue and poor performance.
  3. Water

    Function: The most critical nutrient. Makes up about 60-70% of the body.

    • Transports nutrients (like glucose) and waste products.
    • Crucial for thermoregulation (regulating body temperature through sweating).
    • A small loss of body water (even 2%) can severely impact performance.
Quick Review: Functions of Nutrients

There are three major roles that food plays in the body:

  1. Energy Provision: Carbs and Fats (mainly).
  2. Body Building and Repair: Protein (mainly), plus minerals (e.g., Calcium).
  3. Regulation and Protection: Vitamins, Minerals, and Water.

II. Balanced Diet and Healthy Eating Principles

A balanced diet means consuming the right variety and proportion of foods to meet nutritional needs and maintain good health.

Understanding Food Proportions

In many countries, guidelines (like the Food Pyramid or Food Plate) stress the importance of certain food groups:

  • Grains/Cereals (Carbohydrates): Should form the largest part of your diet (the base of the pyramid). Essential for energy stores.
  • Vegetables and Fruits (Vitamins, Minerals, Fiber): High importance for regulation and protection.
  • Meat, Fish, Eggs, Legumes (Protein): Essential for repair and growth. Consume in moderation.
  • Fats, Oils, Salt, Sugar: Should be consumed sparingly (the tip of the pyramid).
Key Principles for a Healthy Diet (The VMA Rule)
  1. Variety: Eat many different types of food to ensure you get all the necessary vitamins and minerals.
  2. Moderation: Don't eat too much or too little of any food group. Even healthy foods can cause problems if eaten in excess.
  3. Adequacy: Consume enough nutrients and energy to meet the demands of your training and daily life.

III. Energy Balance and Weight Management

For athletes and healthy individuals, maintaining an appropriate body weight is key to optimal performance. This is achieved through Energy Balance.

A. Defining Energy Balance

Energy Balance is the relationship between the energy you consume (Energy Intake) and the energy you use up (Energy Expenditure).

\[ \text{Energy Balance} = \text{Energy Intake} - \text{Energy Expenditure} \]

1. Energy Intake: The total calories (kcal/kJ) taken in from food and drinks.

2. Energy Expenditure: The calories used by the body for three main processes:

  • Basal Metabolic Rate (BMR): The energy required to keep you alive at rest (breathing, heart function, brain activity). This accounts for the largest portion of expenditure.
  • Thermic Effect of Food (TEF): Energy used to digest and process food.
  • Physical Activity: The energy used during exercise, training, and non-exercise movement.
B. States of Energy Balance

The goal of weight management is to control these states:

  • Positive Energy Balance: Energy Intake > Energy Expenditure.

    Result: Weight gain. If intake consistently exceeds expenditure, the body stores the surplus energy as fat (adipose tissue).

  • Negative Energy Balance: Energy Intake < Energy Expenditure.

    Result: Weight loss. The body must draw on stored energy (fat or muscle) to make up the deficit.

  • Neutral Energy Balance: Energy Intake = Energy Expenditure.

    Result: Weight maintenance (stable body weight). Essential for athletes trying to hold their competitive weight class.

Common Mistake Alert!

Some students believe that exercise alone is enough for weight loss. Remember: You cannot out-train a poor diet. Energy Balance requires managing BOTH what you eat and how much you move.

IV. Nutrition for Physical Performance

Proper nutrition timed around training and competition can significantly enhance performance, delay fatigue, and speed up recovery.

A. Pre-Exercise Meal: Preparing the Fuel Tank

The goal is to top up liver and muscle glycogen stores without causing stomach upset.

  • Timing (2-4 hours before): Consume a meal high in complex carbohydrates (e.g., pasta, rice, bread).
  • Avoid: Meals high in fat, protein, or fibre immediately before exercise, as they take longer to digest and may cause stomach cramps or sluggishness.
  • Closer to Exercise (1 hour): A small snack of simple carbs (e.g., a banana) can provide a final, easily digestible energy boost.
B. During Exercise (Endurance Activities)

If exercise lasts longer than 60–90 minutes, the muscle glycogen stores will become depleted, leading to "hitting the wall."

  • Fuelling: Consume small amounts of easily digestible carbohydrates (sports drinks, gels, energy bars) every 15–20 minutes to maintain blood glucose levels.
  • Hydration: Drink fluids regularly to replace water lost through sweat (see Section C).
C. Post-Exercise Nutrition: The Recovery Window

This is perhaps the most important meal for muscle adaptation and readiness for the next session. The first 30–60 minutes after exercise is known as the Anabolic Window, where the body is most efficient at absorbing nutrients.

We use the 3 R's of Recovery:

  1. Refuel: Replenish muscle glycogen stores. High glycemic index (simple) carbohydrates are beneficial here for quick replenishment.
  2. Repair: Consume protein to repair damaged muscle fibres and promote muscle growth.
  3. Rehydrate: Replace fluids and electrolytes lost in sweat.

Ideal Ratio: Aim for a combination of carbohydrates and protein, typically in a 4:1 ratio (e.g., 60g carbs and 15g protein). Example: Chicken sandwich on whole-wheat bread and fruit juice.

V. Hydration: The Key to Temperature Control and Transport

Dehydration severely affects performance by reducing blood volume, which makes it harder for the heart to pump oxygen to the muscles and hinders the body's ability to sweat and cool down.

A. Causes and Signs of Dehydration
  • Cause: Sweat rate exceeds fluid intake.
  • Early Signs: Thirst (already a sign of 1-2% dehydration), dry mouth, reduced urine output (dark yellow urine).
  • Severe Signs: Dizziness, headache, muscle cramps, and increased core body temperature (risk of heat stroke).
B. Fluid Replacement Strategies

Water is usually sufficient for short sessions, but prolonged or heavy exercise requires more:

  • Before: Drink 500-600 mL 2-3 hours before exercise.
  • During: Drink 200-300 mL every 15-20 minutes.
  • After: Replace 125-150% of the weight lost during exercise (e.g., if you lost 1 kg, drink 1.25 to 1.5 L of fluid).
  • Sports Drinks: Recommended for long-duration or intense exercise, as they replace electrolytes (minerals like sodium and potassium lost in sweat) and provide easily absorbed carbohydrates.
Did You Know?

The colour of your urine is a simple and reliable hydration indicator. Pale straw yellow means you are well-hydrated. Darker yellow or amber means you need to drink more water!

Summary: Your Nutritional Checklist for Success

You now understand that nutrition is not separate from your training—it is an integral part of it. Always prioritize complex carbohydrates for sustained energy, protein for muscle repair, and water for optimal body function. Remember that a neutral Energy Balance is the goal for stable health and weight, and timed nutrition is the secret weapon for peak performance!

Keep up the great work!