Nutrition Essentials

Study Notes

A nutrient is a substance that the body needs.
The body requires nutrients for energy, tissue building/repair, regulating metabolism, and transporting substances.
A balanced diet ensures the body receives all necessary nutrients.

Carbohydrates are macronutrients that include sugar, starch, and fiber.
Sugar and starch provide short-term energy for the body.
Sugar (simple carbohydrate) provides quick energy, found in fruits, vegetables, honey, juice, and candy.
Starch (complex carbohydrate) provides energy over a longer period, found in pasta, bread, cereals, rice, legumes, tubers, and root vegetables.
Fiber cannot be digested but aids in preventing constipation, found in fruits, vegetables, and whole grain cereals.

Fat is a macronutrient that provides sustained, long-term stored energy.
Found in oils, butter, margarine, salad dressings, cream, nuts, cheese, meat, fries, chips, and pastries.
Saturated and trans fats should be limited.

Protein is a macronutrient used for building and repairing tissues and providing energy when other sources are unavailable.
Found in meat, poultry, fish, eggs, legumes, tofu, nuts, and other sources.

Vitamins are micronutrients that help regulate metabolism.
Metabolism is the process of converting food into energy for the body.
Vitamins are found in fruits, vegetables, meats, meat substitutes, milk, nuts, and other foods.

Water helps regulate metabolism and transports substances within the body.
The human body requires 2-3 liters of water daily.
Water is present in almost all foods but is high in beverages, fruits, and vegetables.

Carbohydrates, fats, and proteins all provide energy to cells.
Energy is measured in calories or kilojoules (kJ).
1 calorie = 4.18 kJ
Each nutrient provides a standard amount of energy per gram. Carbohydrates = 17 kJ/g, Protein = 17 kJ/g, Fat = 37 kJ/g.

Cellular respiration is the chemical reaction that releases stored energy from nutrients.
This process uses glucose (sugar) and oxygen to produce carbon dioxide, water, and energy in the form of ATP.

The average daily energy requirement for a 13-15-year-old adolescent is 10,500 kJ (approximately 2500 calories).
Energy is needed for basal metabolism, physical activities, and digestion/absorption.
To maintain weight, energy consumed must equal energy expended.
To gain weight, energy consumed must exceed energy expended.
To lose weight, energy expended must exceed energy consumed.

Indicators are substances that react chemically in the presence of a specific substance, used to detect its presence.
Good indicators produce detectable reactions (e.g., color change, gas release, precipitate formation, energy variation).
Examples of everyday indicators: pregnancy tests, breathalyzers, smoke detectors, and pH testing kits.
Specific tests including the Biuret test for proteins. A positive result is a pink/purple color change.

Energy is essential for work and motion.
It cannot be created or destroyed, only transformed.
Forms of energy:
- Chemical energy: stored in chemical bonds.
- Mechanical energy: related to movement and position.
- Thermal energy: stored due to the internal movement of particles.
- Radiant energy: carried by light and electromagnetic waves.
Energy transformation: Changing from one form of energy to another.