Transcript Chapter 1: Food Choices: Nutrients and

Food Choices:
Nutrients and
Nourishment
Chapter 1
What Is Nutrition?
-The study of how
your body uses the
food that you eat.
You Are What you Eat!!
Nutrients and Nourishment
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The science of nutrition
Identifies amount of food we need
 Recommends best food sources
 Provides helpful and harmful components
Helps us make better choices
 Improves our health
 Reduces our risk of disease
 Increases our longevity
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Nutrients and Nourishment
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Why do we eat the way we do?
 Food choices
 Ways we use food
 Food preferences
 Inborn and environmental
 Sensory
 Cognitive
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Influences on Food Choices
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Sensory Influences
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Taste
 Sweet, sour, bitter, and salty
 Umami
Smell
Texture
Color, moisture, and temperature
Influences on Food Choices
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Physiological changes
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Accompany aging process
Teeth and gum deterioration
Bone loss
Diminished taste sensitivity
Influences on Food Choices
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Cognitive influences
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Habits
Comfort/discomfort foods
Cravings
Advertising and promotion
Social factors
Nutritional value and health beliefs
Influences on Food Choices
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Environmental
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Economic factors
Lifestyle
Culture
 Religion
The “American diet”
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Influences on Food Choices
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Economic factors
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Where you live and climate
 Food that is accessible
 Food cost
Limited finances shift food choices
 Does a healthier diet cost more?
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Influences on Food Choices
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Lifestyle
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Fast-paced society
Eating away from home
Convenience foods
Main dishes made from scratch
Influences on Food Choices
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Cultural influences
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Human relationships
Culture defines our attitude
 Knowledge
 Beliefs
Customs
 Habits
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Symbolic
Influences on Food Choices
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Cultural influences
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Religion
 Part of some rites, symbols, and customs
Cultural cuisine
 Increase in cultural interactions
 Increase in exposure to various cuisines
Influences on Food Choices
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Cultural influences
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The “American diet”
 “Typical” is as diverse as Americans
themselves
 Heavy on meat and potatoes
 Light on fruits and whole grains
 Eating more cereals, snack foods, soft
drinks, and noncitrus juices
Introducing the Nutrients
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Definition of nutrients
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Food = mixture of chemicals
Essential chemicals = nutrients
What is a Nutrient
A nutrient is a chemical substance in food that
helps maintain the body. Some provide energy. All
help build cells and tissues, regulate bodily
processes such as breathing. No single food
supplies all the nutrients the body needs to
function.
Introducing the Nutrients
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Other chemicals in food
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Flavors and colors
Caffeine
Phytochemicals
 Plant chemicals
 Important health functions
Introducing the Nutrients
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Six classes of
nutrients
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Carbohydrates
Lipids (fats and oils)
Proteins
Vitamins
Minerals
Water
Introducing the Nutrients
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General functions of nutrients
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Supply energy
 Carbohydrates, lipids, and proteins
Contribute to cell and body structure
Regulate body processes
Introducing the Nutrients
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Classifications of nutrients
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Macronutrients
 Carbohydrates, lipids, and proteins
Micronutrients
 Vitamins and minerals
Organic (contain carbon)
 Carbohydrates, lipids, proteins, and vitamins
Inorganic
 Minerals and water
Carbohydrates:
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Provide a source of energy for the body
When taken in they are broken down into
glucose and distributed through the blood
stream
Simple: are sugars = rapidly absorbed =
insulin spikes
Complex: are starches = slow to absorb=
more dense
Introducing the Nutrients
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Carbohydrates
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Sugars and starches
Functions
 Energy source
Food sources
 Grains
 Vegetables
 Legumes
 Fruits
 Dairy products
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Fats:
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Most concentrated source of energy
Found in both plant and animal sources
Saturated: animal products = limited intake
Unsaturated: Plant source = “good fats’
Trans fats: Man made = = worst kind
Introducing the Nutrients
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Lipids
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Triglycerides (fats and oils),
cholesterol, and phospholipids
Functions
 Energy source, structure,
regulation
Food sources
 Fats and oils
 Meats
 Dairy products
 Some plant sources
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Introducing the Nutrients
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Proteins
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Made of amino acids
Functions
 Energy source, structure,
regulation
Food sources
 Meats
 Dairy products
 Grains, legumes,
vegetables
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Proteins:
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Proteins are complete structures that consist
of smaller molecules called amino acids.
These are the building blocks of the body
Essential – cannot be made in the body so
must be taken in through diet
Non Essential- can be made in the body or
taken in through diet
Introducing the Nutrients
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Vitamins
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Fat-soluble
 A, D, E, K
Water-soluble
 B vitamins, vitamin C
Functions
 Regulation
Food sources
 All food groups
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Introducing the Nutrients
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Minerals
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Macrominerals and trace
minerals
Functions
 Structure, regulation
Food sources
 All food groups
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Introducing the Nutrients
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Water
 Most important nutrient
 Functions
 Temperature control
 Lubrication of joints
 Transportation of nutrients and wastes
 Food sources
 Beverages
 Foods
Photo © PhotoDisc
Introducing the Nutrients
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Nutrients and energy
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Energy sources
Measure of energy
 Kilocalorie
The calorie is a pre-SI metric unit of energy. It was first defined by
Nicolas Clément in 1824 as a unit of heat.
In most fields its use is archaic, having been replaced by the SI unit of
energy, the joule. However, in many countries it remains in common use
as a unit of food of energy.
Specifically, a calorie is the amount of energy, or heat, it takes to raise
the temperature of 1 gram of water by 1 degree Celsius (1.8 degrees
Fahrenheit). One calorie is equal to 4.184 joules, a common unit of
energy used in the physical sciences
Calories per gram:
Protein
1 Gram = 4 calories
Carbohydrates 1 Gram = 4 calories
Fat
1 Gram = 9 calories
Introducing the Nutrients
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Energy in foods
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Measured in kilocalories (kcal)
Introducing the Nutrients
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How can we calculate the energy available
from foods?
Example
30 g carb x 4 kcal/g = 120 kcalories
10 g protein x 4 kcal/g = 40 kcalories
16 g fat x 9 kcal/g = 144 kcalories
TOTAL = 304 kcalories
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Introducing the Nutrients
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Be food smart
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Managing the percent of macronutrient intake
Example
To limit fat intake to 20–35% of total energy intake:
2,000 kcal food x 0.35 = 700 kcal from fat
700 kcal from fat/9 kcal/g = 77.8 g of fat allowed
per day
Variables which affect nutrient needs:
1. Age
2. Gender
3. Activity Level
4. Climate
5. Health
6. State of nutrition
Introducing the Nutrients
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Obesity: public health crisis
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65% of U.S. adults are overweight or obese
Increases health risks
 Type 2 diabetes
 Cardiovascular diseases
 Cancer
 Gallbladder disease
Introducing the Nutrients
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Obesity: public health objectives
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Reduce prevalence of obesity to 15%
Factors that influence obesity
 Behavior
 Environment
 Genetics
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Applying the Scientific Process
to Nutrition
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Scientific method
See Figure 1.11 on page 20
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Observation
Hypothesis
Experimentation
Publication
Further experimentation
Theory
Applying the Scientific Process
to Nutrition
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Types of studies
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Epidemiological
Animal
Cell culture
Human
 Case control
 Clinical trial
 Placebo effect
From Research Study to Headline
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Publishing experimental results
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Peer reviews of scientific journals
Media publication
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Sorting facts and fallacies
Finding reliable sources