Download Dietary Guidelines For Americans 2010 www.dietaryguidelines.gov

Dietary Guidelines For Americans 2010
www.dietaryguidelines.gov
Background and Purpose
• Created by: United States Department of Agriculture (USDA) and Department of Health & Human Services
(HHS)
• Guidelines first issued in 1980
• Guidelines reviewed, revised (if needed), and issued every 5 years (by law)
• Target audience: Healthy Americans ages 2 years and older
• DG provides information and advice for choosing a healthy eating pattern—one focusing on nutrient dense
foods* and beverages and contributes to achieving and maintaining a healthy weight.
• Such healthy eating patterns incorporate food safety principles so as to avoid food borne illnesses
Specific diseases linked to poor diet and physical inactivity
• Cardiovascular disease
• Type 2 diabetes
• Hypertension
• Osteoporosis
• Certain cancers
 Nutrient-dense foods – def. Foods that provide substantial amounts of vitamins and minerals and relatively
few calories. Foods in nutrient-dense forms are those that are in their low-fat forms and without added
sugars. Ex) apples
Intent of DG
• To summarize and synthesize knowledge about individual nutrients and food components into interrelated
set of recommendations for healthy eating that can be adopted by the public
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Maintaining calorie balance over time to achieve and sustain a healthy weight
Focus on consuming nutrient-dense foods
To reduce risk of food borne illnesses: four basic food safety principles:
• Clean
• Separate
• Cook
• Chill
Chapter 2: Balancing Calories to Manage Weight
Key Recommendations
• Prevent and/or reduce overweight and obesity through eating and physical activity
• Control total calorie intake to manage body weight. For people who are overweight or obese, this means
consuming few calories from food and beverages.
• Increase physical activity and reduce time spent in sedentary behaviors
• Maintain appropriate calorie balance during each stage of life
• Behavioral, environmental, and genetic factors affect body weight
• Calorie balance = relationship between calories consumed from food and beverages and calories expended
in normal body functions (metabolic processes) and through physical activity
*CALORIE BALANCE IS KEY TO WEIGHT MANAGEMENT
To maintain body weight:
• Caloric intake = caloric expenditure
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To lose weight:
Caloric intake < caloric expenditure
To gain weight:
Caloric intake < caloric expenditure
*Healthy eating pattern includes consuming nutrient-dense foods, which are enjoyable, meeting nutrient
requirements, and staying within calorie needs.
Overweight and obese: what do they mean?
 Body weight status can be categorized as: underweight, healthy weight, overweight, obese
• Body Mass Index (BMI) is a tool used to estimate a person’s weight status
Overweight:
• Refers to scale weight
• Compared to standard
• BMI > 25
Obesity:
• Accumulation and storage of excess body fat
• > 20% above ideal body weight
• > 25% body fat for men (more muscle mass in men)
• > 30% body fat for women (genetically have more fat than men for child bearing)
*You can be average or underweight, but you can be over fat and vice-versa
Body Mass Index (BMI)
• Determines if weight is appropriate in relation to one’s height
• For children and adolescents, BMI plotted on growth charts for sex and age
BMI Calculations:
= Weight (kg) / height2 (m2)
= Weight (lbs) * 703 height squared
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Advantages: simple and inexpensive
Disadvantages: muscularity, muscle atrophy (muscle gets big), short stature, edema – not getting the
amount of body fat
Overweight and Obesity
• Increased risk of numerous health problems
• Conditions associated with obesity:
- Type 2 diabetes
- Heart disease
- Certain cancers
- Premature death
The Environment vis a vis obesity
• The environment has contributed to the obesity epidemic – it can promote overconsumption of calories and
discourage physical activity and calorie expenditure
Food supply has changed..
• *Foods available for consumption has changed
• *Average daily calories available/person has increased approximately 600 calories
• *Portion sizes have increased
*Communities with more fast food or quick service restaurants have higher BMIs.
Food choices should be..
• Nutrient-dense
• Low in calories
• Appropriate in portion size
The environment and lack of physical activity
• Due to sedentary behavior – difficult to expend enough calories to maintain calorie balance
• Some obstacles: safety, technology, transportation (people are driven around instead of walking or
bicycling), community planning
Understanding Calorie Needs
Number of calories a person needs each day varies depending upon:
• Age
• Gender
• Height
• Weight
• Level of physical activity (total energy expenditure –TEE)
• Desire to gain, lose, or maintain weight
*Calorie needs usually decrease for adults as they age due to decrease in basal metabolic rate
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The effect of the calorie deficit on weight does NOT depend on how the deficit was produced
A person can decrease caloric intake or increase energy expenditure or a combination of both
What is a calorie?
It is a measure of the amount of energy provided by food.
• It is a way to measure energy released by the body
• By definition, a calorie is the amount of heat needed to raise the temperature of 1 kilogram of water by 1
degree Celsius
• It is energy provided by energy yielding nutrients measured in kilocalories (kcals)
• 1000 calories = 1 kilocalorie
• 1 calorie = 4.184 joules
• When spelled with a capital C, refers to kcals
• Terms kcal and calorie frequently used interchangeably!
• Note: when thinking of calories in relation to food we use the term calorie, whereas in actuality we are
referring to kilocalories
Ex) The food label states that the can of soda has 150 calories. It turns out the calories on food labels are
actually kilocalories. Therefore, a can of soda containing 200 food calories contains 200,000 regular calories.
The same concept applies to exercise. When the console son a piece of exercise equipment says that you
burned 100 calories, it means you burned 100 kilocalories.
Bomb Calorimeter – measures the amount of calories
• Determines the amount of energy in food or a mixture of foods
• Consists of a chamber surrounded by a jacket of water
• Food is dried, placed in chamber, and burned
• The increase in water temp. is used to calculate the amount of energy based on the fact that 1kcal is the
amount of heat needed to increase the temp of 1 kilogram of water by 1 degree Celsius
• Combusting food in bomb calorimeter determines the total amount of energy contained in food
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The body cannot completely digest, absorb, and utilize all of the substances found in food
Nutrients – components of food that are indispensible to the body’s functioning
• Some provide energy
• Serve as building material
• Help repair or maintain body parts
• Support growth
• Classified as macronutrient and micronutrient
Macronutrients:
- Supply energy
- Needed in large amounts to maintain and repair body structures
- Carbohydrates, fats, proteins, water
Micronutrients:
- Needed in small amounts
- Help regulate chemical processes and build strong bones
- Vitamins and minerals: not regulated by the government
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A calorie is NOT a nutrient but certain nutrients contain calories
Provide calories
Few foods or beverages are 100% of any nutrient – most are a combination
Calorie count is the sum of calories provided by each nutrient
3500 Calories = one pound (If you want to lose a pound of body fat in one week, you have to decrease the
amount of Calorie intake a week by 3500 Calories.)
Alcohol provides calories but is NOT a nutrient
Carbohydrates: 4 Calories/gram
Protein: 4 Calories/gram
Fat: 9 Calories/gram (nutrient that supplies the most calories/energy)
Alcohol (calories from a non-nutrient source): 7 Calories/gram
No Calories are derived from water, vitamins, or minerals
 Empty calories – def. High in calories, low in nutritional value
Out of our total daily caloric consumption, from which nutrients should we derive the greatest percent of our
calories? Carbohydrates
Acceptable Macronutrient Distribution range (AMDR)
Macronutrient
% of total calories
Carbohydrates
45-65%
Protein
10-35%
Fat
20-35%
(less than 10% of total energy from saturated fats)
Carbohydrates
• Primary source of calories for most Americans
• Main source of energy for body
• Create energy reserve – storage form-glycogen (immediate energy source – i.e. carb loading for a race)
• Classified as *simple (including sugars):
- Sugars found naturally in foods or added
- Natural sugars: lactose and fructose
- Added sugars: table sugar and HFCS
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*complex (including starches and fibers):
- Fiber can occur naturally or added
Most carbohydrates consumed in form of starches
Ex) grains and potatoes
Protein
• Provides amino acids that assist in building and preserving body muscle and tissues
• Assists in energy metabolism and cell processes
• Complete vs. incomplete protein:
- Complete: contains all 9 essential AA’s
Found in animal products and soybeans
- Incomplete: lack 1 or more essential AA’s
Found in animal and plant foods
• Animal-based protein foods: seafood, meet, eggs, milk, and milk products
• Plant-based protein sources: beans peas, nuts, seeds, soy products
• Inadequate protein is RARE in U.S.
• Recommendation: 0.8g/kg body weight/day
Fats
• Provides most energy out of all macronutrients
• Provides energy during endurance exercise, between meals and in times of starvation
• Essential component of cell membranes
• Insulates and acts as shock absorber for bones and organs
• Types of fat:
- Saturated fatty acids (no more than 10& of total caloric intake – unhealthy)
- Trans fatty acids (keep to zero – unhealthy)
- Monounsaturated fatty acids (healthy)
- Polyunsaturated fatty acids (healthy)
• Under consumption NOT a problem in the U.S.
*Not only the amount, but also the location of fat impacts health
Alcohol
• NOT a nutrient
• Source of calories, few nutrients
• Not a nutrient source
*The total number of calories consumed is the essential dietary factor relevant to body weight, not the relative
proportion of macronutrients in the diet
Calorie density (energy density)
• Amount of calories provided per unit of food weight
• Foods high in water and/or dietary fiber usually have fewer calories/grams and are lower in calorie density
• Foods higher in fat are usually higher in calorie density
Calorie Balance: Physical Activity
• Consider PA when addressing weight management
• 2008 PA Guidelines for Americans – set of PA recommendations for Americans age 6 and older
• PA has many health benefits apart from that related to weight
• Adults: to achieve and maintain a healthy body weight should perform equivalent of 150 minutes of
moderate-intensity aerobic activity per week
PA activity guidelines: children and adolescents (6-7 years)
• Should perform 60 minutes or more of PA daily
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Aerobic:
- Most of 60 or more minutes s/b moderate- or vigorous-intensity aerobic PA/day and should include
vigorous-intensity PA at least 3 days per week
Muscle and bone strengthening:
- As part of the 60+ minutes of daily PA, should include muscle and bone strengthening on at least 3
days of the week
Encourage age-appropriate physical activities that are enjoyable and offer variety
Moderate-intensity PA
• Aerobic activity that increases heart rate and breathing to some extent
• On a scale relative to a person’s capacity: usually a 5 or 6 on Borg scale of 0-10
Ex) brisk walking, dancing, swimming, bicycling on level terrain
Vigorous-intensity PA
• Aerobic activity that greatly increases heart rate and breathing
• On a scale relative to a person’s capacity: usually a 7 or 8 on Borg scale of 0-10
Ex) jogging, single tennis, swimming continuous laps or bicycling uphill
Muscle-strengthening Activity
• PA including, exercise, that increases skeletal muscle power, strength, endurance, and mass
• Includes strength training, resistance training, etc.
Bone-strengthening Activity
• PA that produces an impact or tension on bones, which promotes bone growth and strengthening
Ex) running, jumping rope, lifting weights
Moderate-intensity PA defined
• Moderate-intensity PA = Any activity that:
Burns 3.5 to 7kcal/min or the equivalent of 6 metabolic equivalents or achieves 60-73% of Maximal
Heart Rate – rating of perceived exertion 5-6 (12-14)
• Person should feel some exertion, but should be able to carry on a conversation comfortably during the
activity (talk test)
Vigorous-intensity PA
• Any activity that:
burns > 7 kcal/min or equivalent of greater or equal to 6 metabolic equivalents or results in achieving 7488% MHR – rating of perceived exertion 7-8 (15+)
• Should be intense enough to represent a substantial challenge to an individual and result in a significant
increase in HR and breathing rate
Borg Scale of Rating of Perceived Exertion (on a scale of 6-20)
Rating
Perception of Effort
6
7
very, very light
8
9
very light
10
11
fairly light
12
13
somewhat hard
14
15
hard
16
17
18
19
20
very hard
very, very hard
Metabolic Equivalent (MET)
• Used to estimate the amount of oxygen used by the body during PA
• 1 MET = energy (oxygen) used by the body as you sit quietly, perhaps talking on the phone or reading a
book
• 1 MET = consuming 3.5 milliliters of oxygen per kilogram of body weight
• 1 MET = consuming 1 kilocalorie per kilogram of body weight per hour
Maximal Heart Rate (MHR)
• MHR = 220 – age (baby’s heart rate is 220)
• MHR used to calculate target heart rate zone
• Target heart rate zone (range)
THRZ = 0.6*(MHR) less than or equal to THRZ less than or equal to 0.9*(MHR)
• THRZ indicates exercise intensity needed to improve aerobic fitness
Determinants of Exercise Intensity
• METS
Multiple of resting oxygen consumption
Baseline is 1 MET
1 MET = oxygen uptake at rest
multiples thereof determine exercise intensity
• Heart Rate
Correlation between exercise intensity and HR
• Talk Test (subjective)
Ability to converse
• Perceived Exertion (subjective)
Borg Scale of Perceive Exertion (1-10; 6-20)
Improving Public Health Through Diet and PA
• Eating patterns that are high in calories, but low in nutrients can result in an overweight status but
malnourished
• Nutritionally unbalanced diets can negatively affect one’s health regardless of weight status
• A sedentary lifestyle increases risk of disease
Total Energy Expenditure (TEE):
Total energy used by the body each day
 TEE includes energy required for:
o Basal Metabolism
o Physical Activity
o Thermic effect of Food
 Includes energy used to maintain basic bodily functions such as beating of heart and that needed to process
food and fuel physical activity
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Basal Metabolism: approximately 60-75% of body’s total energy expenditure used for basal metabolism
Includes all involuntary things your body does to stay alive:
o Breathing circulating blood
o Regulating temperature
o Synthesizing tissue
o Removing waste products
o Sending nerve signals
Basal Metabolic Rate (BMR): Rate of energy expenditure under resting conditions
 Rate at which energy is used for these basic functions
 Expressed in kcal/hour
 Includes energy needed for essential metabolic reactions and life sustaining functions
 Does NOT include energy needed for physical activity or digestion of food or absorption of nutrients
 Basal needs affected by:
o Body weight
o Muscle mass: thus, men have higher BMR than females
o Age
o Gender
o Growth rate
 BMR increases with increasing body weight, therefore, BMR is higher in heavier individuals
 BMR increases with increase in lean body weight, therefore, BMR is usually higher in men
 Basal needs altered by certain abnormal conditions:
o Elevation in body temp – increases BMR *For each one degree Fahrenheit increase in temp (above
normal temp), there’s a 7% increase in BMR)
o Explains why fever can cause weight loss
 Low energy diets affect BMR
 Energy intakes below needs may depress resting metabolic rates by 10-20%
Physical Activity
 2nd major component of TEE
 represents metabolic cost of external work including planned activities and ADL (activities of daily living)
 represents approximately 15% to 20% of energy requirements (may vary)
Thermic Effect of Food (diet induced thermogenesis)
 Our energy comes from food, but we need energy to digest food and to absorb, metabolize, and store
nutrients from food
 TEF = energy required for digestion of food and absorption, metabolism, and storage of nutrients
 The increase in energy expenditure causes body temp, to rise slightly for several hours after eating
 Equals approximately 10% (can be as high as 30%) of daily energy expenditure (may vary)
 Since it takes energy to store nutrients, TEF increase with size of meal
 TEF of meal high in fat < TEF of meal high in carbohydrates or proteins
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Reason: dietary fat can be used or stored more efficiently than either carbohydrates or proteins
Metabolic cost of oxidizing or storing dietary fat is only 2% or 3% of energy consumed
Cost of using amino acids by either oxidizing them or incorporating them into proteins is 15% to 30% of
energy consumed
Cost of breaking down carbohydrates or storing it as glycogen is 6-8%
The difference in cost of storing different nutrients as fat means that a diet high in fat may produce more
body fat than a diet high in carbohydrates
Estimated Energy Requirement (EER)
 Represents the average dietary energy intake that will maintain energy balance in healthy person of given
gender, age, weight, height, and physical activity level
 EER (male) = 88.5-(61.9*age)+PA*(26.7*WT+903*HT)+25