Transcript Chapter 2 Planning a Healthy Diet

Chapter 2
Guidelines for Designing
a Healthy Diet
Chapter Outline - 2015
 Diet
planning principles (2.1)
 Evaluating nutritional health (2.2, 2.3)


Levels of nutritional status
Deficiencies
 Science
behind nutritional research (2.4)
 Nutritional Recommendations - DRI (2.5)
 Food Guides

My Plate (2.4, page 54 & Myplate.gov)
 Food

labels (2.7)
Health Claims
Planning a Healthy Diet

Adequate Diet is a diet that provides enough
energy to maintain a healthy diet and provides
nutrients needed for optimal health
 General
philosophy for an adequate
diet….Eat a variety of foods in moderation.
Diet-Planning Principles (5)
1.
2.
3.
4.
5.
Balance
Variety
Nutrient density
Energy density – Kcal control
Moderation
Diet-Planning Principles
 Balance

Diet that provides enough, but not too
much of each type of food
• Don’t want overeating of one food type to
“crowd” out intake of other nutrients….
Diet-Planning Principles
 Variety
- Diet that includes a wide
selection of foods within each food group
• Eat a variety of fruits, not just oranges
• Why?
 Variety
within the fruit and vegetable
groups has the added bonus of increasing
the variety of phytochemicals in your diet.
Phytochemicals
– substances in plants
that may contribute to health
 Phytochemicals

Examples – see page 14
Foods – foods that provide
health benefits beyond those of the known
nutrients
 Functional
Diet-Planning Principles
 Nutrient

Density
Select foods that provide the most
nutrients for the least number of calories
(nutrient dense foods)
• Skim milk versus soda (page 39)
• Foods with few nutrients and many calories
are sources of empty calories.
Diet-Planning Principles
 Energy Density - Kcal Control
 Foods with low-energy density have low kcal
per gram, page 40
• Can eat “a lot” without many calories

Select foods with low energy density for an
intake that meets nutritional needs without
excess kcal intake
Energy Density
10
Energy Density
 Measure
of the kcal per gram of food
 _______ has the highest energy density of
the 3 energy-yielding nutrients.
 Foods

with a high energy density
provide more kcal per gram than low density
foods.
11
Diet-Planning Principles
 Moderation


Eat moderate (small) portion sizes
Moderate your intake of foods high in:
• Added sugars
• Salt
• Saturated and trans fats
• Cholesterol
• Alcohol
Diet-Planning Principles (5)
1.
2.
3.
4.
5.
Balance
Variety
Nutrient density
Energy density – Kcal control
Moderation
Levels of Nutritional Status
1. Desirable/Ideal nutrition

Intake is sufficient to meet daily needs and to
keep nutritional stores full while maintaining a
healthy body weight
Levels of Nutritional Status
2. Borderline nutrition – a subset of
undernutrition in text


Intake is not sufficient to meet daily needs
Drawing upon your stores
• Body is not prepared to handle times of stress

Illness, pregnancy…
• May slows growth and development of fetus and
growing child
Levels of Nutritional Status
3. Undernutrition


Intake does not meet daily caloric and nutrient
needs and nutrient reserves are empty for
some/all nutrients
There is a decline in body functions due to the
lack of nutrients
• Can be life threatening
• Medical intervention required
Under-nourished
 Populations






at increased risk:
anyone living in poverty
• especially infants, children, pregnant women,
elderly
elderly in general, including those living in nursing
homes
pregnant teens
drug and alcohol addicts
individuals with eating disorders
anyone with prolonged illness, including hospital
patients
Nutritional Deficiencies
 Covert


vs. overt deficiency
Covert or sub-clinical – deficiency may be
detected by lab tests, but not outward signs of
the deficiency
Overt or clinical symptoms– outward signs of
the deficiency
Nutritional Deficiencies
 Primary


vs. secondary deficiency
Primary – inadequate intake of the nutrient
Secondary – body doesn’t absorb adequate
amounts, excretes too much….
• Body “mishandles” the nutrient

Diet history helps distinguish between these
Overnutrition
4. Over-nutrition – 2 aspects

excessive caloric intake that leads to obesity
• Increase risk of obesity related diseases



heart disease, diabetes….
overuse of vitamin supplements that leads to
toxicity
Page 42 – overview levels nut. status
Malnourished
 Comment
on a commonly used term….
 The term malnourished is most commonly
used in reference to chronic undernutrition
 It can also be used in reference to anyone
with chronic poor nutrition that results in
failing health
The ABC’s of evaluating
nutritional status
 Anthropometric
data
 Biochemical tests
 Clinical assessment
 Dietary intake
 Environmental status

Living conditions….from background
information
see page 44
Evaluating Nutritional Status
Background - Personal History
1.
•
•
•
•
•
2.
SES
Social history - living situation, marital status
Personal and family health history
Medications, supplements taken
Educational level…..
Anthropometric data (A)
– Height and weight
– Waist circumference
– % body fat
Evaluating Nutritional Status
3. Biochemical Assessment (B)
Laboratory tests, eg
– Cholesterol level
– Iron, potassium, vitamin D levels
– Liver enzyme function
4. Clinical Assessment (C)
Physical exam
– Hair, skin, eyes, tongue…
– Blood pressure
Evaluating Nutritional Status
5. Diet History (D)
-
Typical foods eaten
Food journal
6. Environmental Assessment (E) – part of
background/personal history
Science Of Nutrition
 Nutritional
recommendations are based on
scientific research.
 Recommendations attempt to define
adequate intake.
The Science of Nutrition
 One

of the newest sciences
New branch is nutritional genomics
• Study of the interaction of nutrients with
DNA/genes and how those genes impact health
 Like
all sciences, nutrition is based on
scientific research
Scientific Method
Observations  Questions
2. Hypotheses  Predictions
3. Test hypotheses/predictions
4. Analyze data and draw conclusions
5. Share results
1.
Observations and Questions
 Make
observations about diet and health.
These observations lead to questions
For example:


The incidence of breast cancer is much lower
in Japan than in the U.S.
Diet in Japan is rich in…..while in U.S. diet is
rich in ……
 Question?:
Develop Hypotheses and Make
Predictions
– tentative explanation of the
observations or answer to the question
 Hypothesis
prediction – If the hypothesis is
true what else is true?
 Make
Experiments
 Conduct
experiments to test the
predictions


Easier said than done when people are
involved!
We’ll consider research designs later/soon.
One Experimental Design
 When
possible, randomly assign subjects
to either a control of experimental group



Goal is for two groups to be as similar to each
other as possible
Control Group – either no change to diet or
given a placebo
Experimental group – diet changed or given
a supplement
Experimental Design
 Compare
the health/lab values of the two
groups before and after the diet change.

Example – DASH diet study
Analyze results…
 Analyze
results
 Draw conclusions about the validity of the
hypothesis
 Test alternate hypotheses
 Share findings


Publish in nutritional journals
Present findings at conferences
Common Research Designs
1.
Epidemiological study (observe)



2.
Cross-sectional
Longitudinal
Case-control study
Experimental (intervene)


Animal studies
Human clinical trials
• Double blind study

Lab studies

Page 47
The Science of Nutrition
1. Epidemiological studies
• Study of populations
• Look for correlations between dietary practices and health
• Nurses Health Study
Epidemiological Studies
Cross-sectional - look for correlations
between diet and health at a point in time
Longitudinal Studies - Follow a group of
people (a cohort) over a period of time
• Look for differences in diet that might account for the
differences in health
Epidemiological Studies
study – compare the diet of
individuals with a condition to that of
healthy individuals
 Case-control

Again, do not change their diet…..just
observe it.
Human Experimental Studies
Often called a Clinical Study
• Randomly assign like people to either
the experimental or control group
• Alter the diet of experimental group as
compared to a control group
• Compare incidence of disease/lab
values/ performance …. of two groups
Types of Clinical Trials
 Blind
experiments
• Subjects do not know which group they are in
 Double
blind experiments
• Neither subjects nor the researchers know which group
the subjects are in until after the experiment is over
• Goal is to avoid bias in the reporting/recording of
the data.
Experimental Studies
Animal Studies
• Controlled studies in lab setting using
animals
• Alter diet of experimental group
• Compare health/lab values of control and
experimental groups
• Benefits? ….
• Drawbacks? ……
Experimental Studies
Lab-Based Studies
• Also called in vitro studies
• Examine impact of a substance on living tissue in a
“test tube”
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The Science of Nutrition

Size matters



Good studies have relatively large sample
sizes
Preliminary studies have smaller sample sizes
Peer review matters

Information in peer- reviewed research
journals is much more credible than that in
popular magazines, TV, Internet
Dietary Recommendations
Dietary Reference Intakes (DRI) – pg 48
RDA – Recommended Dietary Allowances
2.
AI – Adequate Intake
3.
UL – Tolerable Upper Intake Levels
4.
EER – Estimated Energy Requirement
5.
DV – Daily Value
All based on nutritional research.
1.
RDA
Recommended Dietary Allowances
1.

RDA is set to meet the needs of 98% of the
population (without reaching toxic levels)
AI
Adequate Intake (AI)
3.
•
•
AI = average amount of the nutrient that a
group of healthy people consume
AI is set when there isn’t enough research to
set an estimated average requirement
(EAR) or RDA
•
Examples: Vitamin D, water, fiber
UL
Tolerable Upper Intake Level (UL)
4.
•
•
Maximum daily amount of nutrient that
appears safe for most healthy people
Intake above the UL is associated with
toxicity symptoms
•
Most often see with overuse of supplements or
intake of many fortified foods
DRI
Other Recommendations
 Estimated

Energy Requirements (EER)
Caloric intake that will maintain energy
balance in a healthy, active person
• Values given are for “reference” male and female
who is fairly active
 Daily



Value (DV)
Used on food labels
Based on a 2000 kcal diet
Set at high end of RDA
Energy – Why not set
an RDA?
Other Recommendations
 Acceptable
Macronutrient Distribution
Range

or, recommended intake of energy yielding
nutrients
• 45-65% of caloric intake from carbohydrate
• 20-35% of caloric intake from fat
• 10-35% of caloric intake from protein
Diet Planning Guides

Food Group Plans
•
•

Foods within each food group provide similar
nutrients and are from similar food sources
Plan recommends the amount of food to be eaten in
each food group.
Food Group Plans include:


USDA Food Guide (Pyramid/MyPlate)
DASH diet
Old
Food
See
board
for Pyramid
updates!
2005 USDA Food Guide -MyPyramid
Food Pyramid  My Plate (6/11)
USDA Food Guide
 Assigns
foods to 5 (6?) major food groups
 Recommends daily intake levels from
each group

Recommendations vary depending on caloric
needs
 Recommends
weekly intake goals for
several food groups.
MyPlate
 Physical


Activity
Adults should do at least 2 hours and 30
minutes each week of aerobic physical activity
at a moderate level
OR
1 hour and 15 minutes each week of aerobic
physical activity at a vigorous level.
My Plate - Grains
 5-8
ounces bread, pasta, cereal, rice
 Half should be from whole grains




1 slice of bread
½ English muffin, bun
½ cup cooked rice, pasta, cereal
1 ounce dry cereal
Fruits and Vegetables
 Make
half your plate fruits and vegetable!
My Plate - Vegetables
 2-3

cups vegetables
Choose a variety from all 5 subgroups weekly
(see next slide)
 1 cup cooked or raw vegetables
 2 cups leafy vegetables (raw)
 ¾ cup vegetable juice
Eat a Variety of Vegetables
Vegetable subgroups
1. Dark green – broccoli and dark greens
2. Red, orange, yellow – carrots, peppers, winter
squash, sweet potatoes
3. Legumes – black beans, kidney beans,
soybeans, navy beans….
4. Starchy – corn, peas, potatoes, lima beans
5. Other – green beans, brussel sprouts,
mushrooms, tomatoes, vegetable juices…
My Plate - Fruits
1
– 1 ½ cups of fruit
Consume a variety of fruits
No more than 1/3 from juices
 1 orange, apple, banana (all medium size)
 ½ grapefruit
 ½ cup canned fruit or berries
 3/4 cup fruit juice
My Plate - Dairy
3
cups/serving dairy
Choose low/no-fat options
• 1 cup milk



80 kcal, skim
100 kcal, 1% milk
159 kcal, whole milk
• 1 cup yogurt
• 1 ½ ounces cheese (170 kcal for cheddar)
• Calcium enriched soy milk
Food Plate - Proteins
 5-6

½ ounces meat and meat alternatives
Meat, poultry, fish, eggs, seeds, nuts,
legumes – ounce equivalents
•
•
•
•
½ ounce nuts
1 egg
1/4 cup cooked legumes = 1 ounce
1 tablespoon pb
My Plate - Oils
 Oils




– 5-7 teaspoons per day
Olive oil
Canola oil
Corn oil
Vegetable oil
My Plate – Empty Calories
 Fats




and sugars – eat sparingly
Butter, margarine
Cream, sour cream, cream cheese, mayo.
Candy, soda, sugar, honey….
Sports drinks, energy drinks
My Plate
 Strengths:
 Drawbacks:
Putting the Plan into
Action
Copyright 2005 Wadsworth Group, a division of Thomson Learning
Food Labels
 Ingredient

Listed by weight in product (most to least)
 Serving


list
size
Set by gov’t for each food type
Not the same as the MyPlate serving
Food Labels
 Nutritional
content compared to Daily
Values


Daily Values are estimates of the needs of
2000 kcal per day consumer
Not the same as RDA – why?
Food Labels
 Specific



nutrition facts
Kcal/serving
Kcal from fat
Total fat, grams and % Daily Value (DV)
• Grams saturated fat, % DV
• Grams trans fats – added 2006


Cholesterol (mg and % DV)
Sodium (mg and % DV)
Food Labels

Nutrition Facts, cont’d

Total grams carbohydrate
• Grams sugar
• Grams and % DV: fiber


Grams protein
% DV:
•
•
•
•
Vitamin A
Vitamin C
Iron
Calcium
Food Labels
 “Health”
claims allowed on food labels are
regulated by the FDA




Law changed in 2003 to allow more health claims
Much more confusing now
Now health claims with limited evidence can now be
put on labels with a “disclaimer”/explanation.
Pages 68/69
Food Labels
Food Labels
 “Structure-function”
claims do not require
FDA approval

Cannot mention a disease or symptom
 Limited
regulation of claims on dietary
supplements (since 1994)
Food Labels
 “May


reduce the risk of heart disease.”
A “health” claim
Regulated and needs FDA approval.
 “Promotes


a healthy heart.”
A “structure-function” claim
No FDA approval or proof needed to make
Other Recommendations
 Other
countries and international
organizations set their own nutritional
recommendations
e.g. World Health Organization (WHO)