Chapter 7

Proteins and Fats All information presented was obtained

from the textbook Food For Today Copyright 2010 by McGraw-Hill

Companies Inc.

Protein Protein helps your body grow and repair itself. Found in animal

products, including meat, poultry, fish, eggs, and dairy products.◦ Also, in plant foods,

especially dry beans and peas, nuts, vegetables, and grain products.

Flickr Image: Taken By Brett Jordan

Structure of Proteins Proteins are part of every cell in your

body. They are made of amino acids.

◦Amino acid is a molecule that combines with other amino acid molecules to make proteins.

◦20 different amino acids are found in protein foods. Different proteins perform specialized tasks.

◦Some combine an form hemoglobin. Hemoglobin: is a protein that transports

oxygen un the blood to all the cells in your body.

Protein Digestion How does protein in your food

become protein in your body?◦Your body breaks down protein into

amino acids. ◦Amino acids combine into proteins

your body needs. ◦Amino acids are absorbed into the

bloodstream and sent to the cells to make new proteins.

Complete and Incomplete

Your body makes some, but not all, amino acids for itself. ◦Essential amino acid: an amino acid

that your body needs but cannot make◦Complete protein: A food that

contains all 9 essential amino acids. Meat, poultry, fish, eggs, milk, and soy

◦Incomplete protein: food that lacks one or more of the essential amino acids. Mixture of them to complete all needed

amino acids.

Need for Protein Proteins have countless roles in the

body. Here are the 5 most important:◦1. Growth and maintenance

Constantly broken down and replaced

◦2. Enzymes Chemical reactions take place in every cell in

your body. Enzymes make this possible.

◦3. Hormones Chemical messengers that help regulate the body.

◦4. Antibodies Play a role in the immune system

◦5. Fluid Balance

How much do you need?!

Teens should get 10 to 30 percent of their calories from proteins.

Adults should get 10 to 35 percent Example:

◦ Teens calorie requirement is 2800.◦ What is the range of calories that this teen needs from protein. ◦ (2800 x .10 = 280) ◦ (2800 x .30 = 840)

Protein has 4 calories per gram◦ Divide those each by 4 to determine the amount in grams. ◦ (70-210g)

Excess Protein Eating to much protein can be harmful

to your body. ◦Hard on the digestive system◦Broken down and stored by the body as fat

Weight gain

◦No need for supplements with proteins or amino acids.

Inadequate Protein Protein-energy

malnutrition (PEM) occurs◦Most common form

of malnutrition in the world.

◦Children do not grow properly

◦Die of starvation◦Eating disorders

and addictions Flickr Image: Taken By: Photo Plod

Protein Food Choices Plant sources have less fat and

more fiber than animal foods◦Usually cost less too!

Variety◦Meat with plant foods◦Just plant foods◦Etc. ◦Page. 90 examples

Flickr Image: Taken by Magic Robot

The Lipid Family •Lipids are a family of chemical compounds found in every cell, both in foods and in the human body. •Two types of lipids:• Triglyceride: is a basic fat molecule• Main component of fatty tissue.

• Sterols: lipids found in cell membranes• Cholesterol

Flickr Image: Taken by Jay Mase

FatsFats are greasy substances, with solid or

liquid, that will not dissolve in water. ◦ Liquid fats are called oils.

High fat foods are usually high in calories◦ Examples: butter, margarine, oils, cream, fried

foods, ice cream, nuts, egg yolks, and whole milk. Visible Fats:

◦ Fats that can be seen (marbling in meat products.)

Invisible Fats:◦ Cannot be seen and is a part of the chemical

composition of the food. Egg yolks.

Why Are Fats Needed?

Fat helps the body absorb vitamins A, D, E, and K. Body fat serves as an energy reserveCushions and protects vital organsProvides warmth Fat is a component of cell membranesHelp you feel full longer after eating (long

digestion time)Enhances the flavor of most foods Add moisture and tenderness, or crispiness to

foods

Structure of Fats Fatty Acid: is the basic building block of

fats. ◦Takes three of to make a triglyceride.

Saturated Fatty Acid: contains all the hydrogen it can chemically hold. ◦Usually solid at room temperature (butter,

meat fat)Unsaturated fatty acid: are missing

hydrogen units◦Monounsaturated: missing one ◦Polyunsaturated: missing two or more

Usually liquid at room temperature (oils)

Essential Fatty Acids Your body makes some,

but not all fats for itself. ◦Essential fatty acid: is a

fatty acid your body needs but does not produce for itself, it must be consumed. Omega-3 : lowers the risk of

heart disease. Found in: sardines, salmon,

trout, herring, flax seeds, kiwi, walnuts, and pumpkin seeds

Flickr Image: Taken by malias

Fat digestion Fats are mainly digested in the

small intestine. ◦Gall bladder release bile which helps

to break down the fatty acid. Fatty acids are absorbed into the

bloodstream- travel to the liver and tissues that need them.

Lipoprotein: fat-protein unit◦Chemical packages

Cholesterol Cholesterol: is a fatlike substance in cells

that is needed for many body processes.◦Helps digest fat, build cells, and make vitamin

D and hormones. Cholesterol circulates in the blood in two

forms:◦LDL: low-density lipoprotein; takes cholesterol

from the liver to wherever it is needed in the body. LDL is known as the “bad” cholesterol. (Build up in artery walls)

◦HDL: High-density lipoproteins; picks up excess cholesterol and takes it back to the liver. HDL is known as the “good” cholesterol.

Diet Affects Cholesterol Saturated Fat

◦Raise the level of LDL cholesterol ◦Meat, Poultry skin, whole-milk, tropical oils

(coconut oil)Polyunsaturated Fat

◦Help lower cholesterol levels if used in place of saturated fats.

◦Vegetable oils, corn oil, soybean oilMonounsaturated Fat

◦Lower levels of LDL and Raise levels of HDL Olives, avocados, nuts, peanut oil, and canola oil.

Trans FatsHydrogenation: turns vegetable oils into

solids. ◦The missing hydrogen is added to the

unsaturated fats, which increases saturation. Shortening and most margarines Longer shelf-life and extra flavor

Trans-Fats: hydrogenation forms fatty acids◦ Increase LDL levels and lower HDL levels

Salad dressings, snack food, baked goods, fast foods, and crackers

How many calories of fat?

Most Americans eat TOO much fat; especially saturated fat. ◦ Increase of heart disease, and cancer

You NEED fat in your diet, just in moderation.◦Teens need 25-35 percent of their caloric

intake◦Adults need 20-35 percent of their caloric

intake

Controlling FatEat plenty of fruits, vegetables, and whole-

grain productsChoose fat-free or low-fat milkRemove skin from chicken and turkeyChose lean cuts of meat- trim fat and drain

greaseWatch portion sizesChose fish or lean poultry over red meatLimit fried foodsAvoid trans-fats

Resources Information

◦ All information presented was obtained from the textbook Food For Today Copyright 2010 by McGraw-Hill Companies Inc.

Photographs◦ Slide 2: Flickr Image: Taken By Brett Jordan ◦ http

://www.flickr.com/photos/x1brett/3459052829/sizes/s/in/photostream/

◦ Slide 9: Flickr Image: Taken By: Photo Plod http://www.flickr.com/photos/photoplod/5316022392/sizes/s/in/photostream/

◦ Slide 10: Flickr Image: Taken by Magic Robot http://www.flickr.com/photos/magicrobot/3157414088/sizes/m/in/photostream/

◦ Slide 11: Flickr Image: Taken by Jay Mase http://www.flickr.com/photos/jaymasephotography/5381332769/sizes/s/in/photostream/

◦ Slide 15: Flickr Image: Taken by malias http://www.flickr.com/photos/malias/375664720/sizes/m/in/photostream