Download Chapter 1 What is Nutrition?

Chapter 1: What Drives
Our Food Choices?
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What Drives Our Food Choices?
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What helps us determine our decisions about food?
• Taste and enjoyment
• Culture and environment
• Social reasons and trends
• Weight concerns, body image, and health benefits
• Advertising
• Time, convenience, and cost
• Habits and emotions
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Food Choices: Taste and Enjoyment
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Taste
• Most important consideration in food choices
- More than 10,000 taste buds in the mouth
- Most people prefer salty or sweet
- Degree varies, partly because of genetics
- Taste for fat may be genetically linked
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Food Choices: Taste and Enjoyment
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Texture
• Affects likelihood of enjoying foods
• 30% of adults dislike foods that are slippery
• Preference begins early in life and makes people resistant
to change
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Food Choices: Culture and Environment
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Culture
• What we eat growing up affects our food preferences
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Environment
• Availability and accessibility
• Size and shape of plates and glassware
• Packaging of foods
• Lighting
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Food Choices: Social Reasons and Trends
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Eating is an important way to bond with others
• The more people who are present at a meal, the more
you’ll likely eat
- Meal size increases by over 40%
• Activities influence the food and amount eaten

Trends also affect food choices
• Frozen vegetables in the 1950s
• Prewashed, peeled, sliced, or diced fresh vegetables
today
• “Organic” foods
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Food Choices: Weight Concerns, Body
Image, and Health Benefits
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Choices can be influenced by current state of health
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People select foods based on perception
• Avoid foods associated with weight gain or loss

Awareness of food effects on health can increase effort to
improve eating habits
• Functional foods may provide additional health benefits
beyond the basic nutrient value
• Phytochemicals (anti-oxidants) may play a role in
fighting chronic diseases
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Food Choices: Advertising

Manufactures spend $10 to $15 billion annually on food
advertising
• It works, especially on young people
How many food ads have you seen today…
- While watching television?
- While serving the Internet?
- While driving to school?
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Food Choices: Time, Convenience, Cost
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People want to
• Spend less than 15 minutes preparing a meal
• Purchase foods prepared and partially prepared
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People eat out more
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Cost affects the selection of fast food versus more
nutritious meals
• In the long run the health issues of excess fast-food
consumption increases health care cost
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Food Choices: Habits and Emotions
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Daily routine and habits affect when and what you eat
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Emotions can sometimes drive food choices
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What Is Nutrition?

The science that studies how nutrients and compounds in
foods nourish the body and affect body functions and
overall health

The study of the relationship between food and health

Exploration of how food is:
• Digested
• Absorbed
• Transported
• Metabolized
• Used or stored in the body
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What Is Nutrition?

Good nutrition
• Reduces the risk of the
leading causes of death
• Helps prevent harmful
diseases and conditions
• Reduces the risk of
developing obesity,
diabetes, and high blood
pressure
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What Are Nutrients?
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Compounds in foods that sustain body processes
• Building blocks
• Energy
Six classes of nutrients that are found in foods
• Carbohydrates
• Fats (lipids)
• Proteins
• Vitamins
• Minerals
• Water
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We Are What We Eat
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Water is the most abundant nutrient found in foods and in
the body
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Carbohydrates, fats, proteins, vitamins, and minerals make
up the rest
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Note that foods also contain nonnutritive compounds, such
as phytochemicals and fiber
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Nutrients in Foods and in the Body
Figure 1.1
Most Nutrients Are Organic

Organic compounds contain carbon or carbon–carbon
bonds.
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Carbohydrates, proteins, lipids, and vitamins are organic
nutrients

Minerals and water do not contain carbon and are classified
as inorganic compounds
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The Chemical Composition of the Six
Classifications of Nutrients in Food
Figure 1.2
Essential Versus Nonessential Nutrients
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Essential nutrients
• Must be consumed from food
• Cannot be made in the body in sufficient quantities to
meet its needs and to support health
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Nonessential nutrients
• Can be made in sufficient quantities in the body to meet
the body’s requirements and to support health

Nonessential nutrients can become essential under some
circumstances
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Some Nutrients Provide Energy
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Energy is the capacity to do work
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The body derives energy from certain nutrients
• Energy-yielding nutrients
- Carbohydrates
- Lipids (fats)
- Proteins
• Non-nutrient source of energy
- Alcohol
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Energy Measurement
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Kilocalorie (kcals)
• Amount of energy required to raise the temperature of 1
kilogram of water 1 degree Celsius
• Used to express the measurement of energy in foods
• 1 kilocalorie is equal to 1,000 calories (lowercase “c”)
• Calorie (uppercase “C”) is used on nutrition labels to
express the energy content of food
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Calculating the Energy in Foods
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Each energy-yielding nutrient provides a set number of
kilocalories per gram
• 4 kilocalories per gram of carbohydrates
• 4 kilocalories per gram of protein
• 9 kilocalories per gram of fat (lipid)
• 7 kilocalories per gram of alcohol (non-nutrient)

Number of kilocalories in one serving of a given food can
be determined based on
• Grams of carbohydrates, protein, and fat in the food
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Energy in the Body
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Energy is trapped within bonds that keep molecules
together
• Bonds break and energy is released
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Energy is used in multiple bodily functions
• Needs vary according to age, gender, and activity level
• Unused energy is stored predominately as fat
• Using more energy than consumed results in fat
breakdown
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Primary Roles of the Individual Nutrients
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Individual nutrients serve unique roles in the body
• Supply energy
• Regulate metabolism
• Provide structure
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Macronutrients and Micronutrients
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Macronutrients
• Nutrients the body needs in large amounts
• Include the energy-containing carbohydrates, lipids,
proteins, and water
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Micronutrients
• Essential nutrients the body needs in smaller amounts
• Vitamins and minerals
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Carbohydrates
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Body’s main source of energy
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Supply glucose
• Primary source of energy for several body cell types
- Red blood cells
- Brain cells
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Carbohydrates
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Found in most foods
• Breads, cereals, legumes,
nuts, fruits, vegetables,
and dairy products
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Animal products, other than
dairy, do not provide
significant amounts of
carbohydrates
• Eggs, meats, poultry, and
fish
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Lipids
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Fats (triglycerides), oils, phospholipids, and sterols
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Insoluble in water
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Triglycerides
• Source of energy during rest and sleep
• Storage form for excess energy
- Adipose tissue beneath the skin and around several
organs
• The majority of lipids we eat
• Found in margarine, butter, oils, and animal products
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Proteins
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Can be used as energy, but not usually the primary source
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Contain nitrogen and some contain sulfur
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Make amino acids, the basic building blocks
• Used to synthesize, grow, and maintain tissue
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Primary source of tissues in muscle, bones, and skin
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Participate as neurotransmitters
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Proteins
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Play a role in the immune system
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Act as enzymes
• Catalysts and control chemical reactions
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Good food sources
include meats, dairy,
and legumes

Lesser food sources
include whole grains,
vegetables, some
fruits
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Vitamins and Minerals
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Do not provide energy
Involved in numerous key functions in the body
• Metabolism regulation
• Function as coenzymes
- Substances that facilitate the activity of enzymes
• Essential to the structure and function of hard and soft
tissues
Deficiencies
• Fatigue
• Stunted growth
• Weak bones
• Organ damage
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Vitamins and Minerals
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Vitamins
• Water-soluble
- Not stored in the body
- Consumed daily
- Eight B-complex
vitamins and vitamin C
• Fat-soluble
- Stored in body
- Vitamins A, D, E, and K
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Vitamins and Minerals
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Minerals
• Major
- Need at least 100 mg/day
- At least 5 gm in the body
• Trace
- Need less than 100 mg/day
- Less than 5 gm in the body
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Water
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Makes up the majority of all body fluid
Part of every cell in the body
Key body functions
• Essential during metabolism
• Digestion and absorption
- Transport medium that delivers nutrients and oxygen
to cells and excretes waste products through urine
• Maintenance of body temperature
• Lubricant for joints, eyes, mouth, and intestinal tract
• Cushions vital organs
Can not be stored, must replenish daily
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Quick Review
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What Is Credible Nutrition Research?
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Diet trends change frequently
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Scientific knowledge about nutrition is more consistent
• Based on a consensus of research information
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Evaluating Media Headlines with a
Critical Eye
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Dramatic headlines are designed to grab attention
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Dramatic headlines can be misleading
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Ask the following questions
1. Was the research finding published in a
peer-reviewed journal?
2. Was the study done using animals or
humans?
3. Do the study participants resemble me?
4. Is this the first time I’ve heard about
this?
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Steps of the
Scientific
Method
A process used by
scientist to gather
and test information
for the sake of
generating sound
research findings
Controlled
Scientific
Experiments
Figure 1.6
Quick Review
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Sound nutritional advice is based on years of research using
the scientific method
Methods used to conduct research
• Laboratory experiments – animals
• Experimental research – humans
• Observational research
Double-blind placebo-controlled studies
• Subject unaware of receiving treatment versus placebo
• Researcher unaware of who receives treatment versus
placebo
• Gold standard
Observational and epidemiological research valid with
adequate sample size
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What Is Nutrition Assessment?
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Looking at a variety of information
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To assess nutritional status (state of nutrition)
• Healthy
• Malnourished
• Undernourished
• Overnourished
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Provide the basis for dietary recommendations
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Health History
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Patient’s health history
• Acute or chronic illness
• Diagnostic procedures
• Therapies
• Treatments
Family history
• Diabetes
• Heart disease
Weight history
• Overweight in past
• Underweight in past
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Could any of these
increase nutritional
needs or induce
malabsorption?
Nutrition Expert or Quack?
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Registered Dietitian is trained in medical nutrition therapy
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Nutritionist is a generic term with no recognized legal or
professional meaning
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Quack
• Introduces health fears
• Sells services or products to allay fears
• Makes unrealistic promises or guarantees
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Assessing Nutritional Status of a
Population
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Large-scale collection of dietary intake information is
needed
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Usually conducted through national surveys

Collect and publish reliable data used to develop current
dietary recommendations
• The National Health and Nutrition Examination Survey
(NHANES)
• The Behavioral Risk Factor Surveillance System
(BRFSS)
• The Framingham Heart Study
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Healthy People 2020
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A nationwide health improvement program
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Two broad goals
1. Help all Americans increase life expectancy and
improve quality of life
2. Eliminate health disparities among different segments
of the population

Includes 35 focus areas with disease prevention and health
promotion objectives within each area
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Quality of the American Diet
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Americans
• Eat too much protein, sugar, sodium, and saturated fat
• Eat too little fiber and some vitamins (especially A and
E) and minerals (especially calcium)
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85% of Americans eat breakfast
Quality of the American Diet
• Approximately 40% eat the minimum of five fruits and
vegetables per day
• Sugar accounts for 30% of carbohydrate intake
• Fat intake is about 33% of our diet
• 40% take a vitamin or mineral supplement per day
• 90% of meals are eaten away from home
• 50% never eat meals as a family
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Obesity Trends Among U.S. Adults
Over the last two decades, rates of overweight and
obesity have risen significantly in the U.S.
Figure 1.7
Best Dietary Strategy for Health
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Eat a well-balanced diet with a variety of whole foods
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Individuals with dietary restrictions or higher nutrient needs
may benefit from a supplement in addition to consuming a
healthy diet
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