Transcript Class 3. How balanced is the American diet?

Nutrition Preferences and Attitudes
American Diet
White Bread & Sugar/corn syrup
 Beef
 More soft drinks than milk now
 Most common vegetables:
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Potatoes (most often french fries)
Tomatoes (in sauce/salsa/ketchup)
Iceberg lettuce
onions
Since 1970
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Food Choices Change
consumption of soft drinks has increased more than 300%
Fresh egg intake fell from 5.3 eggs per week to 3.5
Milk sales are down but Low-fat milk sales are up 165%
Beef consumption has dropped 9%
Broccoli consumption is up 386%
Cheese is up 76%
vegetables and fruits are up 25%
How Do Choices Change?
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Advertising and Availability
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Knowledge, attitudes, and values help good change
Knowledge about good nutrition precedes good diet
Students improve diets after course in nutrition
Adults change diets when health problems develop
Information leads some to modify eating behavior
and will change choices of more women than men
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Knowledge Isn’t Enough
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Many people know more about the
components of a good diet than they use
Multiple beliefs and experiences are barriers
to change
Change most likely to succeed when benefits
outweigh disadvantages
Individuals decide if change is in best interest
Practice, practice, practice
Nutrition Attitudes, Beliefs, and Values
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“Unconcerned” consumers are disinterested in
diet and health and select foods for other
reasons
“Committed” consumers believe a good diet
prevents illness and consume a good diet to the
best of their knowledge
“Vacillating” consumers are concerned about
diet and health but vary their food choices
depending on the occasion
Successful Changes
Key in making dietary changes is to
determine which ones are most
important and which are easiest
 Most efforts to improve food choices fail
because they are too drastic
 Improvements that last are the smallest
acceptable changes needed
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Changing Food Choices
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Identify your nutrition problems
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Diet analysis
Identify foods you would eat
Identify changes easiest to implement
 A specific change is easier to implement
than a broad notion
 A small acceptable change has better
chances than a drastic change in diet
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Planning for Relapses
Be prepared for relapses
 Relapses don’t mean failure
 People return to old habits because
attempted change was too drastic or
made too many changes at once
 If change undertaken doesn’t work out,
make a midcourse correction
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Healthy Diets: How to Plan Them
Healthy Eating Pyramid/Harvard
DASH DIET
Choose the pyramid that's best for you
Global Eating
Whichever Diet You Choose…
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You must balance energy intake and
outgo
Understanding Energy
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Calorie (large
Calorie or
kilocalorie)
 Unit of measure
used to express
the amount of
energy produced
by foods in the
form of heat
Three Types of Energy-Requiring Processes
Key Terms
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Basal metabolism
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Energy used to support body processes such as
growth, health, tissue repair, and maintenance
Assessed while at rest
Includes energy expended for breathing, heart
pumping, maintaining body temperature, and
other ongoing, life-sustaining processes
Uses 60-75% of total calorie needs
Energy Used for Basal Metabolism
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Men:
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Women:
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BMR calories = body weight (lbs) x 11
BMR calories = body weight (lbs) x 10
Varies ± 20%
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Depending on physical activity, muscle
mass, height, health status, genetic traits
Energy Used in Physical Activity
Energy Used in Dietary Thermogenesis
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Thermic effect of foods or feeding
Energy expended during digestion of food
and absorption, utilization, storage, and
transport of nutrients
Accounts for ~10% of total energy needs
Total Calorie Needs
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Estimated total daily calorie needs equal
the sum of calories used for basal
metabolism, physical activity, and
dietary thermogenesis
Calculating Calorie Needs
Energy in Foods
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“Energy nutrients” supply energy
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Carbohydrates = 4 calories/gram
Proteins = 4 calories/gram
Fats = 9 calories/gram
Alcohol also supplies energy
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7 calories/gram
How Is Caloric Intake Regulated?
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Hunger
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Satiety
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Physical and psychological sensations that lead people to
acquire and ingest food
Causes weakness, stomach pains, irritability
Feeling of fullness or of having eaten enough
Appetite 
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The desire to eat
A pleasant sensation aroused by thoughts of taste and
enjoyment of food
Can override hunger and satiety mechanisms
Energy Balance
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Energy balance occurs when number of calories
used equal number of calories consumed
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Positive energy balance
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Weight is maintained
Calories consumed > calories used
Weight is gained
Negative energy balance
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Calories used > calories consumed
Weight is lost
Key Concepts and Facts
Ideal weight and shape should be based
on health, not fashion or culture
 Rates of overweight and obesity
increasing world-wide
 Disease and disorders related to body fat
increasing
 Location and amount of body fat stores
important to health
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Key Concepts and Facts, cont.
 Causes
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of obesity are complex
Influences on development
Diet
Physical activity
Environmental exposures
Genetic factors
We need to understand calorie need and
balance intake with expenditure.
Weight Status & Body Image
Venus: Europe of
1400s
Twiggy – 1960’s
Weight Status and Body Image
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Ashley Graham,
plus-size model
Weightlifter, today
Body Mass Index (BMI)
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a measure of weight for height to estimate body fat
Ranges of BMI define weights for height
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Underweight (<18.5)
Normal weight (18.5 to 24.9)
Overweight (25-29.9)
Obese (over 30)
BMI calculation same for males and females
BMI = [Weight(lbs)]*[703]/[height(in)]2
BMI = [Weight(kg)]/[height(m)]2
US Adults Too Heavy
Overweight and obesity is at 67% and rising
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for adults
 Obese children aged 6–11 increased from
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Under 5% in 1965, 7% in 1980,
Nearly 18% in 2012.
In 2012, more than one third of children and
adolescents were overweight or obese.
 Obesity is our #1 health problem.
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World-wide Problem
High rates of obesity becoming more
common worldwide
 Europe - 10-25% of adults are obese
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A billion adults worldwide are
overweight
 Obesity is world public health problem
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World Obesity Rates
Obesity and Health
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Obesity is not a healthy state
Increased risk for:
 Diabetes
 Hypertension
 Stroke
 Heart disease
 Certain types of cancer
Life expectancy in overweight/obese adults 3
to 6 years shorter than average
Weight loss lowers blood pressure, LDL
cholesterol, risk of diabetes and increases HDL
cholesterol
No Easy Answer
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Calories do matter,
but focus first on
choosing highquality, healthy
foods.
Use your pyramid
and ideas from
Global Eating
NIH study finds leisure-time physical activity
extends life expectancy as much as 4.5 years
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Leisure-time physical activity is associated with
longer life expectancy, even at relatively low
levels of activity and regardless of body weight,
according to a study by a team of researchers
led by the National Cancer Institute.
People who engaged in leisure-time physical
activity had life expectancy gains of as much as
4.5 years (Nov. 6, 2012, in PLoS Medicine)
BMI Shortcomings
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Weight-for-height and percent body fat do not
always correspond
Muscular people can have “obese” BMI
Inactive normal BMI people can still have too
much body fat
If people retain fluid, BMI may show overweight
but body fat may be low
Measures of body fat are more accurate than
weight-for-height
Assessing Body Fat
Skinfold thickness measures
 Bioelectrical impedance analysis (BIA)
 Underwater weighing
 Others
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Each one has advantages and drawbacks
Location Important
Pear-shaped:
 store fat in hips and thighs (better)
 Apple-shaped: fat around the waist (worse)
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Why “Apple” is bad
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Fat cells of central-body fat deposits are
larger than those around the hips and
“resistant” to insulin
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Decrease ability of insulin to lower blood
glucose
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Insulin and glucose increase over time
Increased Insulin
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triglyceride levels and blood
pressure
 reduces levels of HDL
 increases
risk of hypertension and
heart disease
 promotes the development of
diabetes
Body Fat Distribution
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Waist size is
stronger predictor of
heart disease, stroke,
and diabetes than BMI
(measure horizontally!)
Waist < 40 inches in
men or 35 inches in
women decreases risk
of these diseases
What Causes Obesity?
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Obesity occurs
when calorie intake
exceeds caloric
expenditure
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Cause is complex
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genetics
environmental exposures
diet
physical activity
sleep pattern
Age and slowed metabolic
rate
Heredity
Genetics important in obesity
 Heredity is 25 to 40% of obesity risk
 FEW born with errors in metabolism
 MANY born with traits expressed after
some environmental trigger
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Environmental Triggers
Change from active lifestyle to sedentary
(off-season for athletes)
 Change from home-cooked meals at set
times to lots of empty calorie food available
 Laid off: change from being busy to
at home alone with refrigerator
 Eating out more: large portion sizes served
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Weight Control:
The Myths and
Realities
©2005 Thomson-Wadsworth
Weight Gain and Environment
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Chinese Study
Shows weight
changes when either
a bicycle or
motorized vehicle is
acquired
Three year study
Diet and Obesity
 Weight
gain if
 energy in > energy out
 Excess fat, protein or carb ——>
increased body fat stores
 Type of calories not important
 Number of calories is!
Key Concepts and Facts
Effectiveness of weight-control methods
gauged by ability to prevent regain
 Because a weight-loss product or service is
widely publicized doesn’t mean it works
 Successful weight control characterized by
gradual weight loss
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Distressed over Weight
Americans spend over $33 billion annually on
weight-loss products and services
 Americans are gaining weight faster than
they are losing it
 Obesity in the United States is on the rise
 Only 5 to 10% of people who lose weight
keep it off for more than a year
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Why We fail at weight loss
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A reduction in caloric intake produces weight loss
Fad methods fail, they become too unpleasant
Hunger, deprivation, and depression lead to
regain
Enjoyable eating and exercise habits are needed
to keep excess weight off
Quick weight-loss approaches don’t change habits
Weight Loss Business
More than 29,000 weight-loss products and
services are available
 Most either don’t work at all or don’t
prevent weight regain
 “Quick fix” weight-loss approaches don’t
lead to long-term changes in behavior
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No laws require a product to be effective.
High Protein Diet?
High protein diets
Help people lose weight in the short term
 Pose risks to health
 Do not help people maintain weight loss
 Promote loss by decreasing appetite
 Deprive body of carbohydrates
 Fats are used for energy instead
 Use of fat means increased “ketone bodies”
 Ketones decrease appetite
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Can They Lose It & Keep It Off?
National Weight Control Registry
Popular myth about weight loss:
everyone who loses weight will
eventually gain it back.
This research study has exploded this myth
Includes more than 5,000 individuals who have
lost significant amounts of weight
and kept it off for long periods of time.
National Weight Control Registry
www.nwcr.ws/
Founded in 1993 by
Dr. James Hill of the University of Colorado
Dr. Rena Wing of Brown University and University of
Pittsburgh.
Longitudinal prospective study of individuals 18 years
and older,
Successfully maintained a 30 pound weight loss for a
minimum of 1 year.
National Weight Control
Registry
 Successful weight losers report making substantial
changes in eating and exercise habits to lose weight
and maintain their losses.
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 The average registrant has lost approximately 60
pounds and has maintained that loss for roughly 5
years.
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* Two-thirds of these successful weight losers were
overweight as children and 60% report a family history
of obesity.
*Extensive histories of overweight and
failed dieting attempts
*Participants used diet and exercise to initially lose
weight
 *About half of registry members report that they
initially lost weight on their own
 *About half used a formal weight loss program
or assistance from a health care professional.
 *Both those who lost on their own and those in a
program are meeting RDAs for most nutrients
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What led to success?
  Nearly every subject is currently using diet
and exercise to maintain his/her weight
loss.
Walking is the most frequent physical
activity performed by NWCR
members.
 Weight loss led to significant
improvements in self-confidence, mood and
physical health.
National Weight Control Registry
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There is variety in how NWCR members keep
the weight off. Most report continuing to
maintain a low calorie, low fat diet and doing
high levels of activity.
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78%
75%
62%
90%
eat breakfast every day.
weigh themselves at least once a week.
watch less than 10 hours of TV per week.
exercise, on average, about 1 hour per day.
Does weight loss maintenance become
easier over time?
Obesity Research, 8: 438-444.
For several health-related behaviors, risk of relapse seems to
decrease over time.
Registry members who had maintained weight losses for longer
periods of time said that less effort was needed to stay on a diet and
to maintain their current weight.
Members who had maintained weight losses for both shorter and
longer periods of time derived equal amounts of pleasure from
exercise, low-fat eating and maintaining their weight losses.
As duration of maintenance increases, the effort required to
maintain seems to decrease.
Find a healthy diet and activities you enjoy