Nutrition and Food Choices

What is Food and Nutrition?

• Food is anything that we eat and nourishes our body.
• Food contains substances that perform important functions in our body.
• Nutrition is the scientific way of eating, studying the interactions between living organisms and food.

Physiological Functions of Food

• Provides energy
• Builds and repairs body tissues
• Regulates body processes
• Protects against diseases

Types of Nutrients

• Macronutrients: carbohydrates, proteins, fats, and water
• Micronutrients: vitamins and minerals
• Vitamins:
  • Fat-soluble: vitamins A, D, E, and K
  • Water-soluble: B vitamins and vitamin C
• Minerals:
  • Macro minerals: calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur
  • Micro minerals (trace minerals): iron, manganese, and molybdenum

Nutrition and Physical Performance

• A well-planned eating strategy supports training programs and promotes efficient recovery
• Nutrition affects performance, and everyone has different nutritional needs
• Athletes require more calories, protein, or vitamins than others, and each sport has unique nutritional demands

Nutrition before Training Exercise

• Pre-workout meal stabilizes blood sugar levels, staves off hunger, and minimizes the risk of problems
• Timing of pre-exercise meal is important, aim to eat 2-4 hours before a workout
• Eat 1-2 g of carbohydrates per kg of body weight, or 400-600 calories for a 70 kg person
• Don't eat a big meal just before a workout, and aim to have a meal 2-4 hours before

Hydration before Exercise

• Aim to drink at least 8 glasses of water daily, and more in hot weather or workout days
• Drink before you get thirsty, and avoid loading up with fluid just before a workout
• Drink little and often, rather than large amounts at once

Nutrition during Exercise

• Drink something during exercise lasting longer than 30 minutes
• Take carbohydrates in liquid form during exercise lasting 60 minutes or longer
• Carbohydrate ingestion during exercise improves performance and maintains high plasma glucose levels

Nutrition after Exercise

• Refuel as soon as possible after exercise to rebuild fuel stores and repair damaged muscle fibers
• Aim to rebuild fuel stores and repair damaged muscle fibers within 30-60 minutes after exercise

Basal Metabolic Rate (BMR)

• BMR is the number of calories burned at rest to maintain basic bodily functions.
• It accounts for 60-75% of daily calories burned.
• Factors that influence BMR include age, nutrition, and activities.

Calculating BMR

• For females: BMR = Wt (kg) x 0.9 kcals/hour x 24 ≈ 22
• For males: BMR = Wt (kg) x 1 kcal/hour x 24 = 24

Physical Activity Level (PAL)

• PAL is the ratio of overall daily energy expenditure to BMR, measuring lifestyle activity.
• PAL values range from 1.2 (mostly inactive) to 1.9 (very active).

Daily Calorie Needs

• Multiply BMR by PAL to calculate daily calorie needs.
• Eating fewer calories leads to weight loss, while eating more leads to weight gain.

Carbohydrates

• Carbohydrates are made up of carbon, hydrogen, and oxygen (CHO).
• They provide energy and are found in both plant and animal sources.

Proteins

• Proteins are the building blocks for new tissues and repair of body cells.
• They are found in both plant and animal sources and provide amino acids.
• Proteins help in building and repairing muscle tissue, and work with carbs to boost recovery after exercise.
• Athletes have higher protein requirements than non-active people.

Fats

• Fats are energy-containing nutrients found in food.
• They are essential for optimal health, making up part of cell membranes and providing energy for exercise.
• Fats are stored in adipose tissue in the form of triglycerides.

Nutrition

• Nutrition is the scientific study of eating and how food affects the body.
• It focuses on how nutrients contribute to the fuel supply needed by the body to perform exercise.
• Sports nutrition is the practical science of hydrating and fueling before, during, and after exercise.

Nutrients

• Nutrients are chemical substances in food that provide a needed function in the body.
• There are two main types of nutrients: macronutrients (carbohydrates, proteins, fats, and water) and micronutrients (present in small quantities but essential for the body).