Chapter 10: Food for LifeChapter Review

What you should have learned:

•How diet effects the body•How the body processes and uses food•How to read nutrient labels•How to analyze diets

Why it is important

•How well your body functions depends on your food and lifestyle choices. You need to make informed decisions to protect your long-term health and well-being. Take charge or your own health!

10.1•Our bodies need a source of energy to keep going.

•Every day throughout your lifetime, your body uses the foods and drinks you consume to help carry out life processes.

•To achieve its maximum performance, your body needs more than just any food or drink.

•We need a balanced diet to help it run efficiently.

10.1 Assessing nutrients

•Nutrition is a branch of science that studies foods and how the body uses them.

•Nutrients are substances found in foods that provide nourishment to our bodies.

•Nourishment and energy help the body to maintain its cells, tissues, and organs, and to support growth and development.

Malnutrition

•Occurs when essential nutrients are missing from a diet.

•It can occur when people eat too little•It can also occur if people eat enough

volume but make poor food choices, and are therefore missing important nutrients.

Malnutrition

•Malnourished people often suffer from high levels of sickness and disability.

•They have shorter life spans.•May die from starvation.•Children who lack nutrients may not grow

properly and suffer brain damage.

What nutrients do we need?

•Carbohydrates•Proteins•Fats•Vitamins•Minerals•water

Carbohydrates

•In the form of sugars and starches are the primary source of energy for your body

•Fibre helps move food through digestive tract

•Examples: rice, whole grains, breads and cereals, potatoes, and pasta

Proteins

•Build and repair tissue•Regulate chemical activity•Provide energy only when carbohydrates

and fats are not available

•Examples: meat, fish poultry, eggs, milk products, dried peas and beans, nuts and cereal

Fats•Provide energy• Insulate•Absorb fat-soluble vitamins•Structural component of nerve and brain

tissue•Enable cells to function•Cholesterol is found in animal meat usually

•Examples: butter, margarine, nuts, oils and red meats

Vitamins

•Help carry out life functions such as growth and reproduction

•Eating a variety of foods provides adequate amounts of vitamins A, B, C, D, E and K.

Minerals

•Structural component of body tissues•Help carry out life functions

•Eating a variety of foods provides adequate amounts of calcium, phosphorous, magnesium, iron, and iodine for health

Water

•Helps dilute and dispose of body wastes and toxins

•Moves nutrients•Controls body temperatures

•Drink at least 2 litres of water a day!

Testing for Nutrients

•Biuret solution tests for protein•Iodine solution tests for starch•Benedict’s solution tests for glucose•Brown paper tests for fat

10.2 Analyzing Diets

•Diet refers to the amount and type of food you eat every day.

•The easiest way to obtain the nutrients your body needs is to eat a mixed diet – a diet that contains a wide variety of foods.

•Canada’s food guide classifies food into four food groups: grain products, fruits and vegetables, milk products and meat and alternatives.

Food Labelling

•Provide us with a lot of nutritional information.

•Helps us to make informed choices•Easy to compare products in terms of

their nutrients.

Vegetarian Diets

•Choose not to eat animal products•Vegans – do not eat any animal products•Because they do not eat meat, they

usually lack protein.•Their diet is high in fibre, and low in

harmful forms of fat•Drawback is that it can be low in iron and

vit B•May also lack calcium

Fad Diets

•A “fad diet” refers to a current diet or craze about how or what people should eat.

•Often involve weight loss

•Examples: Atkin’s, cabbage soup, grapefruit diets.

10.3 Digestive System

•Involves three processes:▫Mechanical digestion – moving parts,

teeth and stomach break food into smaller pieces

▫Chemical digestion – enzymes break food down into smaller particles

▫Absorption – molecule-sized products of chemical digestion move into the bloodstream.

Mouth

•Teeth – mechanical digestion.•Reduces the size of the food and mix it

with saliva•Chemical digestion - Enzymes break down

starch into glucose

•Remember – chewing the cracker

Stomach

•Mechanical digestion – stomach churns the food.

•Mixes it with acid and enzymes•Acid activates enzymes to digest food and

turn it into liquid form.•Once partially digested, the stomach

releases it into the small intestine

Small Intestine

•Most of the chemical digestions and nearly all of the absorption of nutrients occurs in the small intestine.

•Carbs – enzymes break carbs into sugars, and are absorbed into the blood stream.

•Protein – enzymes split into simpler components for absorption

•Fats – bile breaks fat into smaller pieces.

Large Intestine

•Absorption continues•Water, minerals and vitamins are

absorbed into the bloodstream.•Stores waste materials in the form of

feces.

10.4 Role of Diet

•Choosing too many fats causes several problems:▫Body has to work harder to digest fats▫Excess fat in digestive system may cause

upset stomach and cause you to throw up▫High fat diets can cause fatigue and lack of

energy▫Cholesterol from fatty foods blocks arteries▫Overtime, fats cause weight gain.

Skipping meals…

•When you have not eaten for a long period of time, your blood sugar levels are low

•In order to conserve energy, your body may slow down

•As a result you may feel drowsy and unable to concentrate.