Chapter 30.2-Food and Nutrition

Food Energy- Measured in calories

- calorie- Amount of heat needed to raise the

temperature of 1 gram of water 1 degree Celsius

- Dietary Calories- Also called kilocalories- Equal to 1000 calories- Written with capital C

What is Food Used For?- Energy

- Build and repair body tissues- There are at least 45 different

components in food that the body needs that it can’t make itself

- These components are called nutrients

Nutrients

- Water- Found in all cells

- Necessary for chemical reactions

- Helps maintain body temperature

- 1 liter of water a day is necessary to replace what is lost

- Lost through urination, sweating, breathing

Nutrients- Carbohydrates

- Provide about 4 Cal/gram- Simple carbs provide quick energy- Complex carbs take longer to break

down, and provide energy over a longer period of time

- Complex carbs provide fiber, or cellulose, which helps move waste through the digestive system

- Complex carbs with lots of fiber are healthiest to eat

Carbs and Stored Energy

- Carbs that are not immediately used can be stored as a complex carb

- Converted into glycogen- Stored in the liver, muscles, and

brain

- Carbs that are not used can also be turned into body fat

Nutrients- Fats

- Provide about 9 Cal/gram- Help the body absorb fat-soluble

vitamins- Are a part of cell membranes- Provide insulation and protect

organs- Can act as hormones- Store energy long-term

- Unsaturated fats are the healthiest to eat

Nutrients- Proteins

- Provide about 4 Cal/gram- Are the raw materials for many body

parts, especially muscles- Also control chemical reactions

(enzymes!)- Can act as hormones

- Provide 8 essential amino acids

- Lean meat is the healthiest to eat (93% fat or less)

Nutrients- Vitamins

- Organic molecules that the body needs in very small amounts

- Needed for chemical reactions

- Fat-soluble vitamins- A, D, E, K- Can be stored in fat tissue

- Water-soluble vitamins- B complex, C- Cannot be stored, and are lost through

urination

Nutrients- Minerals

- Inorganic molecules that the body needs in very small amounts

- Many of them are elements

- Water-soluble, and are lost through sweat, urination, and solid waste

What Should You Eat?- A balanced diet is based on Percent

Daily Values- For a 2000-Calorie diet- Calories can change with age, activity

level, and age- 2200 Cal for female teens, 2800 Cal for male

teens

- A balanced, healthy diet contains:- Lean proteins for 8 essential amino acids- Complex carbs for energy and fiber- Unsaturated fats in small amounts