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(1)

Lesson Overview

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Lesson Overview

Food and Nutrition

THINK ABOUT IT

When you feel hungry, do you feel weak and just a little bit lazy?

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Lesson Overview

Food and Nutrition

Food and Energy

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Lesson Overview

Food and Nutrition

Food and Energy

Why do we need to eat?

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Lesson Overview

Food and Nutrition

Energy

When food is burned, most energy in the food is converted to heat, which is measured in terms of calories.

A calorie is the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius.

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Lesson Overview

Food and Nutrition

Energy

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Lesson Overview

Food and Nutrition

Raw Materials

Chemical pathways can extract energy from almost any type of food. So why does it matter which foods you eat?

Food also supplies the raw materials used to build and repair body tissues. A healthy diet ensures that your body receives all of these required

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Lesson Overview

Food and Nutrition

Nutrients

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Lesson Overview

Food and Nutrition

Nutrients

What nutrients does your body need?

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Lesson Overview

Food and Nutrition

Nutrients

Nutrients are substances in food that supply the energy and raw materials your body uses for growth, repair, and maintenance.

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Lesson Overview

Food and Nutrition

Water

The most important nutrient is water.

Many of the body’s processes, including chemical reactions, take place in water.

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Lesson Overview

Food and Nutrition

Water

Water is lost from the body in sweat, urine, and with every breath that you exhale.

Humans need to consume at least 1 liter of fluid each day to replace what is lost.

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Lesson Overview

Food and Nutrition

Carbohydrates

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Lesson Overview

Food and Nutrition

Carbohydrates

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Lesson Overview

Food and Nutrition

Carbohydrates

The starches found in grains, potatoes, and vegetables are complex carbohydrates, or polysaccharides.

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Lesson Overview

Food and Nutrition

Carbohydrates

Excess blood sugar is converted into glycogen, which is stored in the liver and in skeletal muscles.

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Lesson Overview

Food and Nutrition

Carbohydrates

Whole-grain breads, bran, and many fruits and vegetables contain the complex carbohydrate cellulose, often called fiber.

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Lesson Overview

Food and Nutrition

Carbohydrates

The bulk supplied by fiber helps muscles move food and wastes through your digestive system.

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Lesson Overview

Food and Nutrition

Fats

Fats, or lipids, are an important part of a healthy diet.

Fats help the body absorb fat-soluble vitamins and are part of cell

membranes, parts of nerve cells, and certain hormones.

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Lesson Overview

Food and Nutrition

Fats

The raw materials used to build fats include fatty acids and glycerol.

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Lesson Overview

Food and Nutrition

Fats

Based on the structure of their fatty acid chains, fats are classified as saturated or unsaturated.

When there are only single bonds between the carbon atoms in the fatty acids, each carbon atom has the maximum number of hydrogen atoms and the fat is saturated.

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Lesson Overview

Food and Nutrition

Fats

Unsaturated fats have one or more double bonds between carbon atoms, which reduces the number of hydrogen atoms in their fatty acids.

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Lesson Overview

Food and Nutrition

Fats

Food manufacturers often modify unsaturated fats in vegetable oils by adding hydrogen to them. These processed fats are called trans fats.

Trans fats are solid at room temperature. They also have a longer shelf life than unsaturated fats.

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Lesson Overview

Food and Nutrition

Proteins

Proteins supply raw materials for growth and repair of structures such as skin and

muscle.

Many enzymes are made of proteins.

Proteins also have regulatory and transport functions.

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Lesson Overview

Food and Nutrition

Proteins

Proteins are polymers of amino acids.

The body is able to synthesize only 12 of the 20 amino acids used to make

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Lesson Overview

Food and Nutrition

Proteins

Meat, fish, eggs, and milk generally contain all eight essential amino acids. Foods derived from plants, such as grains and beans, do not.

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Lesson Overview

Food and Nutrition

Vitamins

Organic molecules that the body needs in very small amounts are called vitamins.

Most vitamins are needed by the body to help perform important chemical reactions.

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Lesson Overview

Food and Nutrition

Vitamins

There are two types of vitamins: fat-soluble and water-soluble.

The fat-soluble vitamins A, D, E, and K can be stored in the fatty tissues of the body. The body can build up small deposits of these vitamins for future use.

The water-soluble vitamins, which include vitamin C and the B vitamins, dissolve in water and cannot be stored in the body.

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Lesson Overview

Food and Nutrition

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Lesson Overview

Food and Nutrition

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Lesson Overview

Food and Nutrition

Minerals

Inorganic nutrients that the body needs, usually in small amounts, are called

minerals.

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Lesson Overview

Food and Nutrition

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Lesson Overview

Food and Nutrition

Nutrition and a Balanced Diet

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Lesson Overview

Food and Nutrition

Nutrition and a Balanced Diet

What is meant by the term balanced diet?

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Lesson Overview

Food and Nutrition

Nutrition and a Balanced Diet

The science of nutrition—the study of food and its effects on the body—tries to determine how food helps the body meet all of its various needs.

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Lesson Overview

Food and Nutrition

Balancing Your Diet

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Lesson Overview

Food and Nutrition

Balancing Your Diet

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Lesson Overview

Food and Nutrition

Balancing Your Diet

The carbon atoms in fats

generally have more C–H bonds than the carbon atoms in

carbohydrates or proteins.

Oxidizing these C–H bonds

releases a great deal of energy. Therefore oxidizing a gram of fat releases more energy than does oxidizing a gram of

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Lesson Overview

Food and Nutrition

Balancing Your Diet

When using food labels, it is important to remember that Percent Daily Values are based on a 2000-Calorie diet. However, nutrient needs are affected by age, gender, and lifestyle.

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Lesson Overview

Food and Nutrition

Maintaining a Healthful Weight

Exercising about 30 minutes a day and eating a balanced diet can help maintain a healthful weight.

Regular physical activity helps to maintain a healthful weight by burning excess calories.

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Lesson Overview

Food and Nutrition

Maintaining a Healthful Weight

The American Heart Association recommends a diet with a maximum of 30 percent of Calories from fat, of which only 7 percent should be from saturated fats and 1 percent from trans fats.

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