Chapter 5 Lesson 2Carbohydrates, proteins and Fats

• Carbohydrates – Starches and sugars found in foods

• Carbohydrates are the preferred source of energy, providing 4 calories per gram

• Depending on the chemical makeup, carbohydrates are classified into 2 types– Simple or complex

Carbohydrates

• Health experts recommend that 55 to 65% of your daily calories come from carbohydrates, mainly complex carbohydrates

Simple Carbohydrates

• Sugars are present naturally in fruits, some vegetables, and milk

• Fructose – Fruits

• Lactose – Milk

• Maltose – grain

• Sucrose – Table sugar

Complex Carbohydrates

• Starches – found in great supply in rice and other grains, seed nuts, legumes (dried peas and beans)

• Tubers – (potatoes, cassava, yams, taro)• Starches are called complex carbohydrates

because they are chemically more complex than simple carbohydrates

• During digestion, starches break down into sugar

The Role of Carbohydrates

• Before body can use carbohydrates it must be broken down into glucose

• Glucose – a simple sugar and IS THE BODY’S CHIEF FUEL

• Glucose not used right away is stored in the liver and muscles as a starch like substance Called GLYCOGEN

The Role of Carbohydrates

• Later when glucose is needed the glycogen is converted back to glucose

• When people consume more carbohydrates than their body need for energy or can store as glycogen, this excess is stored as adipose tissue or fat

Fiber

• Found in the tough, stringy part of vegetables, fruits, and grains, fiber is a special for of complex carbohydrate

• It cannot be digested or used for energy it helps move waste through your digestive system

Fiber

• Helps reduce some types of cancer• Helps reduce constipation, appendicitis• Helps control diabetes and some types of fiber

seem to help lower blood cholesterol• Increase fiber in body by eating an abundance

of fruits and vegetables• Bran cereal, wheat breads, pasta, oatmeal,

brown rice, popcorn• Need 25 grams of fiber per day• Special form of Complex carbohydrates

Proteins

Proteins

• Nutrients that help build and maintain body tissues

• Muscle, bone, skin, connective tissue, teeth, blood and vital organs all contain protein

• Calories provide 4 calories per gram

• Excess protein is converted to fat and stored for storage

Proteins

• Proteins are made of building blocks called AMINO ACIDS

• Your body can make all but 9 of the 20 amino acids

• These 9 are called ESSENTIAL AMINO ACIDS because they must come form food you eat

• Proteins – 2 categories – Complete and Incomplete

Complete Proteins

• Complete proteins – Contain all essential amino acids that come from food you eat that the body needs and in the proper amounts

• These include animal products, such as fish, meat, poultry, eggs, milk, cheese, yogurt, and many soybean products

Incomplete Proteins

• Foods that lack some of the essential amino acids

• Such food sources come from plants:

• Legumes, nuts, whole grains, and seeds

• Eating various incomplete protein sources – Legumes with grains give the equivalent of a complete protein

• P.104

The Role of Proteins

• During life new proteins form constantly to replace damage or worn out body cells

• Proteins in enzymes, hormones and antibodies also help regulate many body processes

Fats

Fats

• Fats are a type of lipid – a fatty substance that does not dissolve in water

• Fats are composed of carbon, hydrogen, and oxygen atoms

• Fats are made of fatty acids

• Fats classified as SATURATED OR UNSATURATED

Fats

• Gram for gram, fats deliver more than twice the energy of either carbohydrates or proteins

Saturated Fats

• Fatty acids are called saturated when the fatty acid hold all the hydrogen atoms it can

• Saturated Fats: Stay solid or semi solid at room temperature

• Animal fats and tropical oils– Palm oils– Palm kernel oil– Coconut oil– Fats in beef, pork, egg yolks, and dairy foods

Unsaturated Fats

• When fatty acid is missing one or ore pairs of hydrogen atoms

• Most vegetable fats are unsaturated: Liquid at room temperature

• Olive oil, canola soybean, corn, cotton seed oils are unsaturated

• *Hydrogenated foods – adding missing hydrogen atoms to food - PEANUT BUTTER, MARGARINE

The Role of Fat

• Fats carry vitamins A,D,E,K into your blood stream and serve as sources of linoeic acid – Essential fatty acid not made in the body but which is essential for growth and healthy skin

• Body fat surrounds and protects vital organs

• Protects body against excessive heat or cold

The Role of Fat

• Body needs only a moderate amount of dietary fat each day

• Average teenage girl: 2,200 calories per day and 66 grams of fat per day

• Average teenage boy: 2,800 calories per day and 84 grams of fat per day

• Too much fat linked to obesity, heart disease, diabetes

• Fat intake no more than 30% daily

Cholesterol

• Fatlike substance produced in the liver of all animals and therefore, found only in foods of animal origins – meats, poultry, fish, eggs and dairy products

• Cholesterol is instrumental in production of sex hormones, vitamin D and protective sheaths around nerve fibers