Overview of Food and Nutrition

Overview of Food

• Food consists of materials consumed by organisms to provide energy for biological activities, enhance physical activity, control body functions, and support the creation of necessary compounds.
• Serves as the only energy source for organisms involved in biological processes.
• Nutritional quality varies among food substances; important for overall health.

Classification of Food Sources

• Plant products: Include fruits, vegetables, grains, herbs, spices, and beverages. Humans rely heavily on plants for sustenance.
• Animal products: Include meat, fish, and eggs. Humans consume both plant and animal-derived foods.

Nutrients

• Nutrients are chemical substances in food essential for nourishment, grouped into several classes:
  • Carbohydrates
  • Proteins
  • Fats
  • Vitamins
  • Mineral salts
  • Water
• Nutritional composition can vary widely among different foods.

Carbohydrates

• Major type of nutrient and primary energy source for the body.
• Digested into glucose, which fuels cells, tissues, and organs.
• Found in foods like bread, beans, milk, potatoes, and sweets.
• Exist in forms such as sugars, fibers, and starches; integral to a healthy diet.
• Excess carbohydrate intake can lead to lethargy, while deficiency can reduce physical performance.
• Energy stored as glycogen and starch is utilized in emergencies.

Proteins

• Derives from Latin word meaning "of major importance"; vital for life.
• Two main types: enzymatic proteins (catalyze metabolic functions) and structural proteins (make up body components).
• Composed of amino acids; sources include meat, fish, dairy, and legumes.
• Essential functions include:
  • Metabolism support
  • Physical component creation and repair
  • Replacement of dead cells and tissues
  • Growth promotion
• Key components like hemoglobin in red blood cells facilitate gas exchange.

Fats

• Essential nutrient originating from both animal and plant sources, offering more energy than carbohydrates.
• Energy derived from fats is approximately 9 calories per gram, while carbohydrates provide about 4 calories per gram.
• Composed of carbon, hydrogen, and oxygen.
• Fat is formed from glycerol and fatty acids; crucial for energy supply.

Key Points on Nutrient Functions

• Carbohydrates are the body's main energy source.
• Proteins are crucial for growth, repair, and metabolic functions.
• Fats provide the most concentrated form of energy.
• A balanced intake of these nutrients is necessary for optimal health and physical function.