HED 200 chapt11_lecture2

Transcription

Chapter 11
Lecture Slides
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Introduction
• Weight loss programs
• Clinical programs
• Medically supervised
• Nonclinical programs
• Commercial programs
• Counselors; usually not health professionals
• Example: Weight Watchers
• Do-it-yourself programs
• Behavior modification
• Diet
• Exercise
Basics of Weight Control
How may Calories are in a pound of body fat?
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1 pound of fat = 454 grams
1 gram of fat = ~ 9 Calories
1 pound of pure fat = ~ 4,086 Calories
Body fat contains some protein, minerals and water
1 pound of body fat = ~ 3,500 Calories
Is the caloric concept
of weight control valid?
• First Law of Thermodynamics
– Energy is neither created nor destroyed
Caloric Concept of Weight Control
• Caloric costs for changes in body mass
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Fat = 9 Calories per gram
Protein = 4 Calories per gram
Carbohydrate = 4 Calories per gram
Water = 0 Calories per gram
• Caloric cost of weight loss may vary
• Loss of body fat, however, costs about
3,500 Calories /pound
Caloric Concept of Weight Control
• Calories from food may vary slightly
– Fat may be stored more efficiently
– Protein may increase the TEF
– Alcohol may be stored as abdominal fat
• However, caloric balance is the key to weight control
How many Calories do I need per day to
maintain my body weight?
• Estimated Energy Requirement (EER) Technique
– Review Chapter 3
– EER is the dietary energy intake predicted to maintain
energy balance in a healthy individual
– EER same as Total Daily Energy Expenditure (TDEE)
• EER components
– Resting energy expenditure (REE)
– Thermic effect of food (TEF)
– Thermic effect of exercise (TEE)
Total Daily Energy Expenditure
Estimated Energy Requirement (EER)
• A key factor is the Physical Activity Level (PAL), which
is the TDEE divided by the BEE. The PAL is used to
determine the Physical Activity (PA) coefficient
Physical Activity Level (PAL)
Institute of Medicine bases the PAL on the amount of
daily physical activity that is the equivalent of
walking at a pace of 3-4 MPH, or 15-20 minutes per
mile
– Low Active (PAL 1.5): Walk 2.2 miles
– Active (PAL 1.75): Walk 7 miles
– Very Active (PAL 2.2): Walk 17 miles
You need not actually walk this amount, but do other
physical activities that are the equivalent of walking
a mile, such as using an elliptical trainer for 12-15
minutes
Sedentary and very active females
22 years old; 132 lbs (60 kg); 55 inches (1.4 m)
Calculating your EER
• Access the MyTracker Program
– www.MyPyramid.gov
• Use the “Standard Option”
• Once enrolled, you may access the site directly
– www.MyPyramidTracker.gov
Calculating your daily energy expenditure
• Other methods
– Calorie Counting Technique
• If body weight is stable
• Calculate daily caloric intake (MyPyramid)
– Simplified technique
• Approximate caloric intake per pound body weight
How much weight can I lose
safely per week?
• Without medical supervision
– Recommended maximal amount
• Adults: 2 pounds/week
• Growing children: 1 pound/week
– Realizable goals
• Adults: 1 pound/week
• Growing children: ½ pound/week
– Weight loss should be body fat
How can I determine the amount of body
weight I need to lose?
• Set realistic goals
– Appearance
– Health
– Sport performance
• Seek professional help if necessary
Determining Weight Loss Goals
• Body Mass Index protocol
– Target body weight is in kilograms (kg)
• Target body weight = Target BMI x height in meters²
– Height in meters = Height in inches x 0.0254
– 67” x .0.0254 = 1.70 meters
• Example of Body Mass Index protocol
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5’7” (1.70 m) male weighs 170 pounds (77.2 kg)
BMI is currently 26.7 (77.2 ÷ 1.70²); slightly overweight
Goal is a healthier BMI of 23
Target body weight = 23 x 1.70² = 66.5 kg (146 pounds)
• Weight loss = 24 pounds
• Weight loss = 14% (24 ÷ 170)
• Body-fat, lean body mass (LBM) percentage protocol
• Target body weight = Lean body mass in pounds
1 ― desired body-fat %
• Example of body fat , lean body mass protocol
– Athlete weighs 150 pounds, is 20% body fat, 80% LBM
• Lean body mass = 120 pounds (150 x .80)
– Goal is 15% body fat
– 120
= 120 = 141 pounds
1.00 – 0.15
0.85
Athlete needs to lose 9 pounds (150 – 141 = 9 pounds)
Behavior Modification
What is behavior modification?
Model system for health improvement
• Knowledge
– Have proper knowledge about benefits of diet and exercise
• Values
– Develop set of personal values or attitudes
• Behavior
– Modify behavior to reflect your values
• Learn new ways to deal with old problems
• For weight control, reduce or eliminate physical or
social stimuli that contribute to
– Excessive caloric intake
– Physical inactivity
• Learn to eat a leaner, healthier diet
• Learn to exercise more
How do I apply behavior-modification
techniques in my weight-control program?
• YOU are the most important component of your weightcontrol program
• YOU must
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Face the fact that being overweight impairs your health
Know that losing weight will improve your health
Establish weight loss as a high priority
Be able to tolerate some discomfort as you make changes
• One of the first steps is to identify your dietary and
exercise behaviors - Keep a 24-hour record
Diet and Exercise Behaviors
• Establish long-range
and short-range goals
– Long-range
• Lose 10-15% of body
weight over 4-6 months
– Short-range
• Lose 1-2 pounds per week
• Small behavior changes
– “ Nothing builds success
like success”
– Small Steps
Small Steps
www.smallstep.gov
• Website provides numerous small steps relative to
diet, cooking, drinking, and exercise that help
promote weight loss. There is a set for children and
another for teens and adults.
Behavior Modification: Suggestions
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Self-discipline, self-control, and advanced planning
Foods to eat
Food purchasing
Food storage
Food preparation and serving
Location
Restaurant eating
Methods of eating
Activity
Mental attitude
Self-discipline, self-control,
and advanced planning
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Establish realistic weight-loss goals
Establish weight loss as a high priority
Think about this priority before eating
Take small helpings deliberately
Plan for a modest daily caloric deficit
Check your body weight on a regular basis
Foods to eat
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Use low-Calorie healthful foods for snacks
Plan low-Calorie, high-nutrient meals
Plan your food intake for the entire day
Eat only foods that require no or minimal processing
Allow yourself small amounts of foods you like, but
stay within daily caloric limits
• Know the Food Exchange system, particularly portion
size and high-fat foods and Calories per exchange
Food purchasing
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Do not shop when hungry
Prepare a shopping list and do not deviate from it
Buy only nutrient-dense foods
Read and compare food labels
Buy natural foods as much as possible
Food storage
• Keep high-Calorie foods out of sight
• Have low-Calorie snacks like carrots and radishes
readily available
Food preparation and serving
• Buy mainly foods that require preparation of some
type
• Do not add fats or sugar in preparation, if possible
• Prepare only small amounts. Be able to visualize one
serving size for any given food
• Do not use serving bowls on the table
• Put the food on the plate, preferably a small one
Location
• Eat in only one place, such as the kitchen or dining
area
• Avoid food areas such as the kitchen or snack table
at a party
• Avoid restaurants where you are most likely to buy
high-Calorie items
Restaurant eating
• When eating out, select the low-Calorie items
• Request your meals be prepared without fat
• Have condiments, like butter, mayonnaise, and salad
dressing served on the side; use sparingly
• Order water, not a high-Calorie beverage
• Be wary of portion sizes as most restaurant servings
contain 2-3 normal servings. Ask for a take-home
container before you eat and put half of your meal in
the box.
Methods of eating
• Eat slowly. Chew your food thoroughly or drink water
between bites
• Eat with someone; conversation slows eating
• Cut food into small pieces
• Do not do anything else while eating
• Relax and enjoy the meal
• Eat only at specified times
• Eat only until pleasantly satisfied, not stuffed
• Spread your total Calories over the day; snack often
Activity
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Decrease the amount of time spent being sedentary
Increase the amount of daily NEAT
Walk more
Use the stairs, not the elevator or escalator
Do exercise snacks. Brisk 10-minute walk
Get involved in physical activities with others
Avoid sedentary night routines
Start a regular exercise program, both aerobic and resistance
exercises
• Schedule exercise as an appointment in your daily planner
Mental attitude
• Recognize that you are not perfect and that lapses
will occur
• Deal positively with your lapse; put it behind you and
get back on your program
• Put reminders on the refrigerator door at home or on
your telephone at work
• Reward yourself for sticking to your plans
Weight maintenance
• Maintaining your new healthy body weight is the key
• Lifelong commitment to healthy diet and exercise
behaviors is needed
• Prevent a lapse from becoming a relapse
– Injury can curtail exercise
– Have alternative exercises you can do
• National Weight Control Registry
– Maintained weight loss for at least 2 years
Dietary Modifications
• To lose weight, the key component is Calories
– One needs to consume fewer Calories than one expends
• Proponents of macronutrient diets
– High carbohydrate
– High fat
– High protein
How can I determine the number of
Calories needed in a diet to lose weight?
• First, calculate how many Calories (C) you need daily to
maintain your current body weight
• Second, estimate how much weight you want to lose each
week.
• Example:
– 35-year old sedentary woman needs 1,820 C to maintain
current body weight at 140 pounds
– To lose 1 pound/week would require a 500 C daily deficit
– 1 pound of fat = 3,500 Calories; 3,500 ÷ 7 = 500 C
– 1,830 ― 500 = 1,330 C day diet
How can I predict my body-weight loss
through dieting alone?
Why does a person usually lose the most
weight during the first week on a reducing diet?
• The goal is to lose body fat, not muscle
• Weight loss via dieting may come from decreased
body stores of carbohydrate and protein and resultant
body water losses, which require no Calories
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Carbohydrate stores may also bind water
Carbohydrate losses: 300 grams
Associated water losses: 900 grams
Total losses: 1,200 grams (1.2 kg), or 2.6 pounds
Water is also lost with muscle protein losses
• Loss of 1 pound occurs with < 3,500 Calorie deficit
Why does it become more difficult to lose weight after
several weeks or months on a diet program?
1. Body water losses decrease
– Body weight losses are now primarily from body fat, which
requires an energy deficit of 3,500 Calories
2. At your lower body weight, you need fewer daily
Calories to maintain this weight
– Example: Male who needs 18 Calories/lb to maintain weight
• 200 lbs x 18 = 3,600 Calories to maintain weight
• 180 lbs x 18 = 3,240 Calories to maintain weight
3. To maintain a set rate of weight loss, you would need
to cut more Calories from the daily diet
What are the major characteristics of a
sound diet for weight control?
• Hundreds of diet plans have been proposed
– Fast and easy diet plans
• No such diet
• Most diet plans focus on macronutrients
– Acceptable Macronutrient Distribution Range
(AMDR)
• Carbohydrate: 45-65% of energy intake
• Fat: 20-35% of energy intake
• Protein: 10-35% of energy intake
Popular Diets (Diet Books)
Diet Plan
Average Daily
Calories
%
Carbohydrates
%
Fat
%
Protein
Weight
watchers
1,450
56
24
20
Atkins
1,520
11
60
29
South Beach
1,340
38
39
23
Volumetrics
1,500
55
23
22
Jenny Craig
1,520
62
18
20
Zone
1,660
40
30
30
Ornish
1,520
77
6
17
Adapted from Consumers Union. Rating the Diets.
Consumer Reports 70 (6):21, 2005.
Low-fat, High-carbohydrate Weight-loss Diets
• Examples of diet plans
– Ornish – Eat More and Weigh Less
– Rolls – Volumetrics
– Glycemic Index diet
• Key point of such diets
– Fruits, vegetables, whole grains
– High fiber content
Low-carbohydrate, High-fat Weight Loss Diets
• Example of diet plans
– Atkins
– South Beach Diet
• Key points of such diets
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Start with 20 grams of carbohydrate daily
Foods rich in fat and protein
May be more satisfying
Gradually increase carbohydrate, but still low
Low in Calories
High-protein Weight-loss Diets
• Example of diet plans
– Zone (40:30:30)
– Possibly Atkins and South Beach
• Key points of such diets
– Protein is 30% or more of energy intake
– Effects of protein
• Increase thermogenesis
• Maintenance of lean body mass
• Decrease levels of ghrelin with eating;
decrease appetite
Balanced Weight-loss Diets
• Examples of diet plans
– Various health profession organizations
• Key points of such diet plans
– Reduced in Calories yet supply all essential nutrients
– Contain a wide variety of foods that appeal to your taste
and help prevent hunger between meals; moderate in fat
– Suited to your current lifestyle and personal preferences
– Provide a slow rate of weight loss; 1-2 pounds/week
– A lifelong diet
Weight-loss Diet Plans
• Current research
– The Calorie content of the diet is the key factor
– Diets varying in carbohydrate, fat, or protein are
equally effective if caloric content is similar
Popular Diets
Diet Plan
Average Daily
Calories
%
Carbohydrates
%
Fat
%
Protein
Weight
watchers
1,450
56
24
20
Atkins
1,520
11
60
29
South Beach
1,340
38
39
23
Volumetrics
1,500
55
23
22
Jenny Craig
1,520
62
18
20
Zone
1,660
40
30
30
Ornish
1,520
77
6
17
Adapted from Consumers Union. Rating the Diets.
Consumer Reports 70 (6):21, 2005.
Is it a good idea to count Calories when
attempting to lose body weight?
• Counting Calories may be helpful during early stages
of a diet
• Learning the Food Exchange System and using Food
Labels helps you learn the caloric contents and
serving sizes of various foods, which can help in the
selection of low-Calorie, nutrient dense foods
• Keep track of foods rich in fat and sugar
What is the Food Exchange System?
How can I determine the number of
Calories I eat daily?
• Carry a notebook with you and a reminder, such as a
rubber band on your finger
• Record your daily food intake, and physical activity, in
detail, as soon as possible
• Record food intake over a 3-7 day period of time
which represents your normal dietary habits
• Use the Food Exchange System or Nutrition Facts on
food labels to record serving size and Calories
• Use measuring devices, such as a measured cup
• Learn to estimate portion sizes
Figure 11.5
Determining Caloric Intake
• Eating out
– Fast-food restaurants
• Nutrition fact sheets
• See Appendix F
– Other restaurants
• Use PDA or cell phone
• Email [email protected]
• Receive response with Calorie, fat, and carbohydrate
content
Determining Caloric Intake
• Enter food record into MyPyramid dietary
analysis program
• You may keep a record of your caloric (energy)
intake over the course of a year
What are some general guidelines I can use in the
selection and preparation of foods to promote weight
loss or maintain a healthy body weight?
• Consumer Reports study of 32,000 dieters who lost
weight and kept it off
– The National Weight Control Registry
• No specific plan but used sensible strategies
– Cut portion sizes
– Eat fewer Calories from fat and sugar
– Eat healthier carbohydrates, fats, and proteins
Guidelines for Weight Control and Healthy Eating
• Twenty (20) guidelines based on reputable sources
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National Weight Control Registry
Consumers Union
Dietary Approaches to Stop Hypertension (DASH) diet
Optimal MacroNutrient Intake for Heart Health diet
(OmniHeart)
1. Decrease caloric intake -- eat more nutrient-dense
foods and fewer energy-dense foods
2. Eat foods that make you feel full
3. Restrict portion sizes
4. Eat less fat
5. Eat fewer and smaller amounts of refined sugar
6. Reduce the intake of both fat and sugar
7. Eat more low-fat dairy products
8.
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10.
11.
12.
13.
14.
15.
Eat more low-fat meat and meat substitutes
Eat more whole, unprocessed carbohydrates
Eat more fruits
Eat more veggies
Consume fewer high-Calorie fat exchanges
Reduce liquid Calories
Limit intake of alcohol
Limit salt intake
16.
17.
18.
19.
20.
Eat slowly
Nibble, don’t gorge
Eat breakfast
Learn to cook
Learn low-Calorie foods
1. Eat more nutrient-dense foods and fewer energydense foods
2. Eat foods that make you feel full
Volumetrics: High-volume, low-Calorie foods
Soups
Salads
Vegetables
Whole grains
3. Restrict portion sizes
Evolution of Coca-Cola
8-ounce bottle
12-ounce bottle
20-ounce bottle
64-ounce fountain serving
Evolution of fast-food hamburgers
Single 4-ounce patty
Double burger
Triple burger
4. Eat less fat
Proposed rationale:
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Rich in Calories
Appetizing and does not rapidly suppress the appetite
Has a lower TEF or higher metabolic efficiency
May be stored preferentially in the abdominal area
Use fat substitutes
5. Eat fewer and smaller amounts of refined sugar
• Reduce intake of sugar-sweetened beverages
• Use sugar substitutes
6. Reduce the intake of both fat and sugar
• May constitute 50% of daily energy intake
7. Eat more low-fat dairy products
• Rich in protein, vitamins and minerals, especially calcium
8. Eat more low-fat meat and meat substitutes
• Very lean meat exchange
• Fish, chicken breast, beef eye of round, flank steak
• 35 Calories, 1 gram of fat
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High in protein
Low in fat
Low in Calories
Rich in minerals (iron and zinc)
9. Eat more whole, unprocessed carbohydrates
• High volume food
• Rich in fiber
• Select 100% whole wheat or whole grain
Guidelines for Weight Control and Healthy
Eating
10. Eat more fruits
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Select fresh fruits
Select canned or frozen fruits in own juices
Avoid fruits in heavy sugar syrups
Limit intake of dried fruits (high in Calories)
Limit intake of fruit juices (high in Calories)
11. Eat more vegetables
• High volume foods
• Low in Calories
• Rich in vitamins, minerals, fiber, phytonutrients
• Many vegetables are listed as Free Food
Exchanges
• Fewer than 20 Calories per serving
12. Consume fewer high-Calorie fat exchanges
• Reduce intake
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Butter
Margarine
Cooking oils
Salad dressing
Mayonnaise
• Most are pure fat
• Use fat-free or low-fat versions
13. Reduce liquid Calories
• Beverages other than milk and fruit juice should have no
Calories
• Sweetened sodas and drinks may be associated with weight
gain and obesity
• Some specialty coffees contain as many Calories as
McDonald’s Big Mac
• Starbucks Choclaty Chip Frappuccino Blended Crème > 500 Calories
14. Limit your intake of alcohol
– A gram contains 7 Calories, comparable to fat
– Calories in alcohol do not replace Calories in a
meal, so total caloric intake is increased
– Selecting low-alcohol beer and wine may help
save Calories
• 64 Calories versus 150 Calories
• Decreased carbohydrate and alcohol
15. Limit salt intake
• Salt may increase appetite
• Salt may increase thirst for sugar-sweetened beverages
• Use herbs, spices and other nonsalt seasonings
16. Eat slowly
• Eating slowly may help curb your appetite
• Eat a low-Calorie soup or salad as an appetizer
• May help curb the appetite for the main course
17. Nibble, don’t gorge
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Eat 5-6 smaller snacks and meals during the day
May help curb the appetite
Use low-Calorie, nutrient-dense foods
100-Calorie snacks
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An apple
A hard-boiled egg
A dozen almonds
3 Hershey’s kisses
3 cups of air-popped, fat free popcorn
18. Eat breakfast
• A hearty breakfast may help curb appetite through
the morning hours
• A high-protein breakfast may be helpful
• Egg substitutes
• Whole wheat bagels with salmon
• Whole grain cereals with skim milk and fruit
19. Learn to cook
• Select healthy foods
• Cook and serve small portions
• Ease of cooking
• Microwaves
• Electric grills
20. Learn low-Calorie foods
• Learn to substitute low-Calorie foods for those
high in Calories
• Know the Food Exchange System
• Practice what you learn
• Gradual transition in small steps
• Whole milk → low-fat milk → skim milk
How can I plan a nutritionally balanced,
low-Calorie diet?
Are very-low-Calorie diets (VLCD) effective and
desirable as a means to lose body weight?
• VLCD are modified fasts (< 800 Calories/day)
• May be used under medical supervision
• Not recommended for typical individual who wants
to lose 10-20 pounds
Is it harmful to overeat occasionally?
• Occasional overeating is not harmful
to dieting, as long as it does not
become a habit
• Try to avoid high-fat meals if prone to cardiovascular
disease
• Rapid weight gain from overeating may occur, but is
not body fat
– Water retention with carbohydrate stores
– Water retention with excess sodium
• Getting back on your weight loss plan will return
body weight to normal
Exercise and Weight Control
Exercise Programs
What role does exercise play in weight reduction
and weight maintenance?
• Physical inactivity is one of the major contributing
factors to the development and maintenance of
overweight and obesity
• Research studies with twins
– The physically active twin had significantly less fat
than physically inactive twin
Two ways to increase total daily energy expenditure
• Decrease the time you are physically inactive
– Reduce TV viewing
– Increase NEAT
Exercise
How to get more into your day!
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Walk to work
Walk during lunch hour
Take family walk after dinner
Do yard work
Wash car by hand vigorously
Pace the sidelines at kid’s athletic games
Park as far as possible from store entrance
Take the stairs instead of the escalator
Walk anytime you can
Two ways to increase total daily energy expenditure
• Decrease the time you are physically inactive
– Reduce TV viewing
– Increase NEAT
• Start a planned exercise program
– Resistance exercise
– Aerobic exercise
• Resistance exercise benefits
– May help preserve lean body mass as muscle
– May help prevent decrease in REE associated with dieting
– May help motivate individuals to a more physically active
lifestyle
• Energy expenditure with resistance exercise
– Relatively low compared to aerobic exercise
– May be increased in circuit-type training
• Resistance training discussed in Chapter 12
• Aerobic exercise benefits
– Most effective means to increase energy expenditure
• Energy expenditure ↑ with ↑ in exercise intensity
• Walking faster expends more energy
• The Long-haul concept
– Average-size male expends
about 100 Calories jogging
a mile
– 3,500 Calories equals 1
pound of body fat
– Need to jog 35 miles to
lose 1 pound
– Jog 2-3 miles daily will lose
2 pounds in a month,
which is the long-haul
concept
Long-haul Concept
• Caloric expenditure in walking and running 1 mile
– Slow, leisurely walking = 0.45 calorie/pound body weight
– Running = 0.73 calorie/pound body weight
• To burn 1 pound of body fat (3500 calories) in 154-lb male
– Walking would burn about 69 calories per mile; need to walk about 50
miles
– Running would burn about 114 calories per mile; need to run about 31
miles
EXERCISE AND WEIGHT CONTROL
Long-haul Concept
• Walk 4 miles daily 5 days a week
Burns 1400 Calories per week
Lose about 5 pounds in 3 months
• Jog/run 4 miles daily 5 days a week
Burns 2300 Calories per week
Lose about 8 pounds in 3 months
– May increase RMR slightly after exercise
– May help prevent the decrease in REE seen with
dieting
• However, may decrease the REE in athletes who are
already lean
– Manifold health benefits
• Reduce abdominal fat
• Reduce symptoms of the metabolic syndrome
– Prevention of initial weight gain
• Prevention of childhood obesity
– Prevention of weight regain
• Maintenance of weight loss
• Essential for lifelong maintenance of healthy body
weight
– If you like to eat but not gain weight, exercise is
the intelligent alternative
Does exercise affect the appetite?
• Short-term effects
– Intense exercise (> 65% VO²max) may ↓ the appetite
• Increased core temperature
• Increased epinephrine
– Exercise before evening meal
• Long-term effects
– A compensatory increase in energy intake
– Individual variability
– Women seem to compensate more and maintain weight
Does exercise affect the set point?
• The settling point
– Some suggest that individual may reach a level of fat and
energy balance at lower levels of body fatness, indicative
of a settling of the set point to a lower level
– May be a limit. Ghrelin increases with increased exerciseinduced weight loss. Ghrelin stimulates the appetite
What types of exercise programs are most
effective for losing fat?
• Aerobic exercise
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Mode
Intensity
Duration
Frequency
Enjoyment
Practicality
Versatility
Aerobic Exercise
• Mode of exercise
– Large muscle groups
– Rhythmic exercises
Aerobic Exercise
• Intensity of exercise
– Beginners should start with low-intensity exercise
– Use the Principle of Progression
– To maximize energy expenditure, exercise at an intensity
appropriate for the amount of time you have to exercise
– Check Appendix B to find high-energy activities for your
body weight
Aerobic Exercise
• Duration of exercise
– The duration concept is probably the most important
factor in total exercise energy expenditure
– Study conducted for 30 months
• Subjects expended either 2,500 or 1,000 Calories/week
• Subjects in 2,500 group lost 25 more pounds
– Time versus distance
• Energy expenditure much greater running for 1 hour versus playing
tennis for 1 hour
– Exercise snacks: 4 x 10 minutes same as 40 minutes
– Intensity and duration are interrelated
– Increase duration as your endurance capacity improves
Aerobic Exercise
• Frequency of exercise
– Weekly energy expenditure
– 3-4 days may be satisfactory if intensity and duration are
adequate
– 6-7 days often recommended for weight control
• Goal for weight control (Duration and Frequency)
– About 2,000-2,500 Calories per week
Aerobic Exercise
• Enjoyment of exercise
– Find an activity you enjoy
• Aerobic dancing
• Singles tennis
• Pickleball
– Treat work as play
• Mowing the lawn with push mower
• Vacuuming the house vigorously
Aerobic Exercise
• Practicality of exercise
– Limitations
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Lack of partners
Lack of facilities
Weather
Costs
– Bias towards walking and running
• Brisk walking ideal for most weight control programs
• Walk or run anywhere
• Low cost and little equipment necessary
– Indoor exercise equipment may be practical
Aerobic Exercise
• Versatility of exercise
– Do a variety of activities weekly
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Run
Cycle
Swim
Elliptical trainer
Racquetball
– Less likely to become bored
– May help prevent overuse injuries
– May provide alternative exercise if you are injured
If I am inactive now, should I see a physician
before I initiate an exercise program?
• Health professional recommendations
– If you are young (20s-30s) and have no risk factors, it is
probably safe to initiate an exercise program
– The older you are, the better the idea to have a medical
exam; it is prudent for all those over age 40
– Be aware of any personal medical problems that might be
aggravated by exercise
– Have a medical examination if you have any coronary heart
disease risk factors
What other precautions would be advisable
before I start an exercise program?
• If overweight and unconditioned, start easy.
– Walking is the recommended exercise
– Walk before you jog
– Progress slowly
• Safety factors
– Cycling safety
– Pedestrian safety
• Meal time
– Avoid strenuous exercise for 2-3 hours after heavy meals
• Be aware of symptoms of heat stress
What is the general design of exercise programs
for weight reduction?
Typical Exercise Sessions
• Warm-up
– Warm up the specific muscles to be used
– Do the same activity as you will do during the stimulus
period, but at a slower pace
– Gently stretch muscles to be used in the stimulus period
• Warm-down or cool-down
– Decrease the intensity of the same exercise used during the
stimulus period for about 5-10 minutes
– Helps maintain blood circulation
– Avoid exercise-associated collapse
– More active stretching of the warm muscles
What is the stimulus period of exercise?
Stimulus Period for Aerobic Exercise
• ACSM/AHA Guidelines presented in Chapter 1
– Intensity
• Moderate
• Vigorous
– Duration
• Minimum of 20-30 minutes
• More for weight loss
– Frequency
• 5 days a week moderate
• 3 days a week vigorous
• Possibly more for weight loss
What is an appropriate level of exercise intensity?
• Variety of techniques to express exercise intensity
– VO2max
– Calories/minute
• Practical methods
– Heart rate
– RPE
– The Talk Test
Measures of Exercise Intensity
• Heart rate
– Manual palpation
– Heart rate monitor
• Heart rate method
• Various formulae to predict maximal heart rate (HRmax)
– Original formula
• 220 - age
– Updated formula
• 207 – 0.7 age
– Formula for physically trained men
• 205 – 0.5 age
– Formula for obese individuals
• 200 – 0.5 age
• Predicted HRmax for 40- and 70-year old male
40
– Original formula
• 220 – age
70
180
150
179
158
185
170
180
165
– Updated formula
• 207 – 0.7 age
– Formula for physically trained men
• 205 – 0.5 age
– Formula for obese individuals
• 200 – 0.5 age
• Maximal heart rate method
– Example: 40-year old male with HRmax of 180
– 60-80% of HRmax = target heart rate range of 108-144
• Heart rate: Target heart rate range (Karvonen method)
– Expressed as a percentage of heart rate range
• Also known as heart rate reserve
• Heart rate range = HRmax – RHR
– Karvonen’s formula
• Target HR = X% (HRmax – RHR) + RHR
– Example
•
•
•
•
•
•
Individual with HRmax of 180 and RHR of 70
Goal is to exercise at 60% of HR range
Target HR = 0.60 (180 – 70) + 70
Target HR = 0.60 (110) + 70
Target HR = 66 + 70
Target HR = 136
• Maximal heart rate reserve method
– Based on maximal (HRmax) and resting heart rate (RHR)
• Target HR = X% (HRmax
― RHR)
+ RHR
– Example: 40-year old male with HRmax of 180, RHR of 70
– Target range of 60-80% of HRmax reserve
• 0.6 (180 ― 70) + 70 = 66 + 70 or 136
• 0.9 (180 ― 70) + 70 = 99 + 70 or 169
– Target heart rate range = 136 - 169
• Ratings of Perceived Exertion
– Scale based on your perception as to how hard
you are exercising
– Scales based on values of 1-10 and 6-20
• The 6-20 scale is related to heart rate
• Add a 0 and the value should be similar to your heart
rate
Exercise Intensity
• Moderate
– 40-60 % of aerobic capacity
– 5-6 on 10-point RPE scale
• Vigorous
– > 60% of aerobic capacity
– 7-8 on 10-point RPE scale
• The Talk Test: Based on respiratory effort
• You can first hear your breathing
– Entering into the lower range of HR zone
• Breathing harder but able to carry on a
conversation in complete sentences
– Moderate-intensity exercise
• Difficult to carry on conversation in complete
sentences
– Vigorous-intensity exercise
How can I determine the exercise intensity
needed to achieve my target HR range?
• Exercise test to measure heart rate and RPE response
– Select your exercise
• Walk, Run, Cycle, Swim, Row, Indoor equipment, etc.
–
–
–
–
–
–
Exercise about 4-6 minutes to reach steady-state HR
Recover after each exercise bout to reduce heart rate
Do about 4-5 bouts of exercise
Do 1st bout very easy
Increase exercise intensity on 2nd and subsequent bouts
Monitor intensity, HR, and RPE responses for each bout
Determining Personalized Exercise Intensity
• Example: Female with HRmax of 200 and RHR of 70
• Target HR range of 50-85% HR reserve = 135-180
• Walk/jog 0.5 mile at increasing speeds
• Test 2 is just below 50% level
• Test 3 is middle range
• Test 4 is at the upper limit
Test
Time
RPE
HR
Min/Mile
1
8:00
11
108
16:00
2
7:10
13
132
14:20
3
6:30
15
156
13:00
4
6:00
18
180
12:00
How can I design my own exercise program?
• Clues from research with successful exercisers
1. Do not exceed your abilities during early stages
Start slowly
Walking slowly ↓ ankle forces in obese persons
Designing your own exercise program
2. Set both short-term and long-term goals
Short: Walk a mile in 15 minutes
Long: Walk the Rock `n Roll Half Marathon
3. Keep a record of your exercise
Buy a pedometer or accelerometer
4. Find the time to exercise
Block out time in your daily planner
Exercise before work, at lunch, or after work
Exercise while watching TV
5. Find a convenient place to exercise
Local fitness facility close to home or work
Buy exercise equipment for home use
Walk, jog, or run anywhere
6. Stay motivated to exercise
Enjoy exercising
Exercise with others
Become skilled at your exercise
Know that exercise will enhance your health
Walking as an Ideal Exercise
• Efficacy
– Aerobic, or brisk, walking
– Goal: 10,000 steps/day
• Practicality
– Convenience
– Cost
• Safety
– Reduced chance of injury
• Graduate to jogging, running
– Interval training
Energy Expenditure during Walking and Running
Walking
Running
Calories/kg/mile
1.0
1.6
Calories/lb/mile
0.45
0.73
Example: 154 pound (70 kg) male
Walking:
70kg x 1.0 Calories = 70 Calories per mile
154 x 0.45 Calories = ~ 70 Calories per mile
Running:
70kg x 1.6 Calories = 112 Calories per mile
154 x 0.73 Calories = ~ 112 Calories per mile
Cool Websites
How much exercise is needed to lose weight?
• The magnitude of exercise needed for weight loss
may be greater than what is necessary to elicit
significant improvements in health
• ACSM/AHA exercise guidelines for health
– 30 minutes of moderate-intensity exercise
– About 200-250 Calories of energy expenditure per session
– 5 days per week totals about 1,000 to 1,250 Calories
• ACSM/AHA notes that more exercise is better
Exercise to Lose Weight
• ACSM position stand on weight control
– 4.5 hours of moderate intensity per week
– Approximately 2,000 Calories energy expenditure weekly
– Expend about 1,500-2,000 Calories weekly via exercise
• Institute of Medicine /National Academy of Sciences
– 60 minutes daily; walking or jogging at 4-5 MPH
– Approximates 2,000 Calories energy expended weekly
From what parts of the body does the weight loss occur
during an exercise weight reduction program?
• Body weight losses via
dieting
–
–
–
–
Some muscle protein
Some glycogen
Some water losses
Some fat losses
• Body weight loss via
exercise
– Mainly body fat
– May increase some
muscle
Should I do low-intensity exercises
to burn more fat?
• Low-intensity exercise
– Caloric energy expenditure is low
– % of energy derived from fat Is high
• Higher levels of exercise intensity
– Caloric energy expenditure increases
– % of energy derived from fat decreases
– However, total caloric expenditure increases and Calories
derived from fat may increase or stay the same
• Remember, exercise training makes one a better fat
burner at all levels of exercise intensity
Is spot reducing effective?
• Studies with local muscular exercise
– Sit-ups and abdominal fat
– Resistance training and upper arm fat
– No effect of exercise on subcutaneous fat
• Exercise-associated fat loss occurs where body fat is
most conspicuous
– Primarily the abdominal area, including visceral fat
• Gluteal fat, as in gynoid-type fat distribution, more
resistant to change
Is it possible to exercise and still
not lose body weight?
• Body changes with exercise
What about the five or six pounds a person may
lose during an hour of exercise?
• Rapid weight losses
– Sweat
– 1 pint = 1 pound
• May lose 10-12 pounds or more in a summer
workout
• Regain body weight with fluid intake
Comprehensive Weight-Control Programs
• Comprehensive program
– Behavior modification
– Diet
– Exercise
• Most important feature
– Maintenance of stable healthy body weight
• Lifelong commitment
What is more effective for weight control—
dieting or exercise?
• Dieting alone may be an effective means to lose
excess body fat
– Increasing protein content may help maintain muscle
– Some indicate dieting alone to maintain weight is designed
to fail in the long run
• Exercise alone may also be an effective means to lose
body fat
– Dietary energy intake needs to remain constant
Dieting and Exercise for Weight Control
• Combination of dieting and exercise is the most
effective approach to weight control
– A proper diet can control energy intake
– A proper aerobic and resistance exercise program provides
multiple benefits
•
•
•
•
Expends caloric energy
Prevent decrease in lean body mass
Maintain resting energy expenditure (REE)
Exercise may improve dietary compliance
• Average member has lost about 70 pounds and has
kept it off for 6 years
• National Weight Control Registry: Key behaviors
–
–
–
–
Eat a low-Calorie diet; low in fat and high in carbohydrate
Eat breakfast; reduce hunger later in the day
Watch only a limited amount of television
Do about 60 minutes or more of physical activity daily;
walking is the favorite exercise. Also engage in aerobic
classes and resistance training. Expend about 2,000
Calories weekly through physical activity
– Weigh themselves frequently; daily or several times a
week; helps prevent a lapse from becoming a relapse
If I want to lose weight through a national or local
weight-loss program, what should I look for?
•
•
•
•
•
•
•
•
Proper qualifications of health professionals
Medical screening
Reasonable weight goal and rate of weight loss
Individualized program
Behavior modification component
Planned diet and exercise program
Weight maintenance phase
Written contract with risks/benefits explained
Selecting a health club or fitness facility
• Qualification of the staff
– No national standards for personal trainers
– Check certification
• American College of Sports Medicine (www.acsm.org)
• American Council on Exercise (www.acefitness.org)
• National Strength and Conditioning Association (www.nsca-lift.org)
• Variety and availability of exercise equipment
What type of weight-reduction program is
advisable for young athletes?
• American Academy of Pediatrics recommendations
– Gradual weight loss over realistic time frame
• Not to exceed 1-2 pounds per week
– Eat enough to cover the energy costs of daily living, growth,
and energy for sport participation
• Carbohydrate (55-65%); fat (20-30%); protein (15-20%)
–
–
–
–
Lose excess body fat, not muscle or water by dehydration
Lose weight by both diet and extra exercise
Maintain body weight once obtained; no weight cycling
Discuss weight loss with health-care professional and family
What is the importance of prevention in a
weight-control program?
• Treatment of obesity is difficult
• Prevention appears to be the key approach
• Small changes to prevent creeping obesity
– Walk 2,000 more steps daily
– Remove 100 Calories from daily diet
– This combination will prevent 1.5 pound weight gain
monthly
Figure 11.16
Prevention of weight gain
• Importance for children
– Neural circuits may be formed; difficult to eradicate
• Need multipronged efforts
–
–
–
–
–
Government set standards for ads to children
Food manufacturers produce healthier products
Communities plan recreational facilities
Schools provide daily physical education
Parents provide healthy foods and limit sedentary behavior
Weight Control
• The Bottom Line
Eat less, move more
Diet and Exercise for Weight Control
• Eat less
– Fat
– Sugars and refined carbohydrates
• Consuming less fat and sugar is
often all that is needed to reduce
daily caloric intake by 200-300 calories
• Eat more
– Whole grains
– Fruits and vegetables
– Lean fish, poultry, meat
– Low fat dairy products
• Move more
– Daily activities
– Planned exercise
Exercise, Diet & Body Weight
• Useful Web sites
www.MyPyramid.gov
Estimated energy expenditure
Click MyTracker
Enter physical activity
Click Energy Balance
www.MyPyramid.gov/kids
Programs for children
www.Americaonthemove.org
Suggestions for exercise and diet for
weight control
www.smallstep.gov
How to incorporate exercise and
healthy nutrition into daily life; ideas
for adults, teens, children

HED 200 chapt11_lecture2

Transcription

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