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Chapter 9
Designing Weight Management
and Body Composition
Health and longevity are threatened when a person is
either overweight or underweight.
Overweight and obesity increase
one’s risk of developing serious
cardiovascular, pulmonary, and
metabolic diseases and disorders.
Individuals who are underweight
may have a higher risk than others
of cardiac, musculoskeletal, and
reproductive disorders.
Definitions and Classifications
• Obesity: excessive amount of body fat relative to
body weight; body mass index (BMI) at least 30.0
• Overweight: BMI between 25 and 29.9 kg/m2
• Underweight: BMI less than 18.5 kg/m2
• To identify children and adolescents who are
overweight, the 85th and 95th percentile BMI
values are used; cutoffs for age and sex are still
under discussion.
Trends in Overweight and
Obesity (see also Table 9.1, p.233)
• According to World Health Organization (2007):
• More than 1.6 billion adults are overweight.
• Over 400 million are obese.
• By the year 2015 the number of overweight people
globally is estimated to increase to 2.3 billion.
• Adults: Prevalence of overweight and obesity varies
among countries, depending in part on the level of
• In the U.S., 34% are obese (BMI > 30 kg/m2),
• 2 out of 3 are overweight (BMI = 25-29.9 kg/m2)
Trends in Overweight and
• Children and adolescents (6-19 years): Prevalence at risk
for overweight (BMI of 85th-95th percentile) in Canada and
the United States ranges from 29% to 35% .
• Since 1980 the number of overweight American children
has doubled, and the number of overweight American
adolescents has tripled.
Types of Obesity
• Fat distribution (pattern) in the body may be more
important than total body fat for determining one’s risk
of disease.
• Abdominal fat is strongly associated with diseases such
as CHD, diabetes, hypertension, and hyperlipidemia
• Android: -Upper body obesity - typically male pattern;
apple shape; localization of excess body fat mainly in
the upper body; upper-body obesity (most men)
• Gynoid: Lower body obesity - typically female pattern;
pear shape; localization of excess body fat mainly in the
lower body; lower-body obesity (most women)
Causes of Overweight and
• Physical inactivity
• Overeating
• Positive energy balance: energy consumed (food and beverages)
exceeds energy expended (exercise plus resting energy
• For every 3500 kcal of excess energy accumulated, 1 lb (0.45 kg) of
fat is stored in the body.
• Will be stored or lost depending on direction of energy balance
(positive or negative)
• A negative energy balance is produced when the energy expenditure
exceeds the energy input. People can accomplish this by reducing the food
intake or increasing the physical activity level.
Basal Metabolic Rate (BMR)
• Energy need and expenditure are measured in kilocalories
(kcal). A kilocalorie is defined as the amount of heat needed
to raise the temperature of 1 kg (2.2 lb) of water 1° C.
• BMR = Measure of the minimal energy (kcal) needed to
maintain basic and essential physiological functions
• Varies according to age, gender, body size, and body
• For assessment of BMR, the individual needs to be rested
and fasted and should be in a controlled environment.
Resting Metabolic Rate (RMR, REE)
• Practical alternative to BMR
• Defined as energy required to maintain essential
physiological processes in a relaxed, awake, and
reclined state
• Also known as resting energy expenditure (REE)
Total Energy Expenditure (TEE)
• TEE = (BMR or RMR) + dietary thermogenesis (i.e.,
energy needed for digesting, absorbing, transporting, and metabolizing foods) +
physical activity
• The gold standard for measuring TEE is the doubly
labeled water (with deuterium and oxygen-18)
method. This method is expensive and requires
considerable expertise and specialized equipment.
• TEE estimated via age- and gender-specific
prediction equations (see table 9.3)
Energy Expenditure
• Energy expenditure during basal, resting, or
activity states can be measured in laboratory
settings through indirect calorimetry.
• Energy expenditure is estimated from oxygen
utilization. Every liter of oxygen consumed per
minute yields approximately 5 kcal (see table 9.2).
• One MET equals the relative rate of oxygen
consumption of 3.5 ml·min−1 for each kilogram of
body weight (3.5 ml·kg−1·min−1)
• For specific physical activities, energy expenditure
is typically expressed in METs (see chapter 4 and
appendix E.4)
Energy Expenditure - RMR Regulation
• Thyroxine is extremely important in regulating
RMR. Underproduction of thyroxine can reduce
RMR 30% to 50%.
• Growth hormone, epinephrine, norepinephrine,
and various sex hormones may elevate RMR as
much as 15% to 20%. (increase during exercise and may be
responsible for the elevation in RMR after cessation of exercise.)
Energy Storage – Obesity Concerns
• Obesity is associated with increases in both the number and
size of fat cells
• Obese individuals have a higher fat cell number (hyperplasia)
and size (hypertrophy)
• Hyperplasia occurs rapidly during the first year of life and
again during adolescence but remains fairly stable in
adulthood, except in cases of morbid obesity.
• Epidemiological studies suggest that weight gain in the first six
months of life is primarily a gain in fat and that this time
period is critical for development of obesity
• Caloric restriction and exercise are effective in reducing
hypertrophy size but not hyperplasia in adults
Energy Storage – Obesity Concerns
• Approximately 25% of the variability among individuals in
absolute and relative body fat is attributed to genetic factors,
and 30% is associated with cultural (environmental) factors
• Hill and Melanson (1999) suggested that the major cause of
obesity in the United States is our environment.
• Over the past 30 years, the U.S. population has been exposed
to an environment that strongly promotes the consumption of
high-fat, energy-dense foods (increased energy intake) and
reliance on technology that discourages physical activity and
reduces the amount of physical activity (decreased energy
expenditure) needed for daily living.
Weight Management Principles
and Practices
• Key components: proper nutrition and physical activity
• Weight management does not always mean weight loss;
client may need to gain weight.
• The best method for negative energy balance is a
combination of dietary restriction and exercise.
• To gain weight, client must maintain positive energy
• “Weight Management Principles” (p. 239, next slide)
summarizes principles and practices underlying the
design of weight management programs.
Weight Management Principles
Physically Active Lifestyle
• Daily aerobic exercise
• strength and flexibility exercises
• increased participation in recreational activities
such as bowling, golf, tennis, and dancing
• increased physical activity in the daily routine at
home and work through restricting use of laborsaving devices such as escalators, power tools,
automobiles, and home and garden appliances.
Healthful Eating
• Consume a variety of nutrient-dense foods
within and among the basic food groups.
• Limit intake of saturated and trans fats,
cholesterol, added sugars, salt, and alcohol.
• Meet recommended intakes within energy
needs by adopting a balanced eating
Weight Management
• To maintain healthy body weight, balance
calories from foods and beverages with
calories expended.
• To prevent gradual weight gain, make small
decreases in food and beverage calories
and increase physical activity.
Physical Activity
• Engage in at least 30 minutes of moderate-intensity
physical activity, above ADLs and occupational
requirements, on most days of the week.
• Greater health benefits are obtainable by engaging
in more vigorous or longer bouts of physical
• To manage and maintain healthy body weight,
engage in approximately 60 minutes of moderateto vigorous-intensity exercise, most days of the
week, and eat within caloric intake requirements.
Physical Activity (continued)
• To sustain weight loss, participate in at least 60
to 90 minutes of daily moderate-intensity
physical activity and eat within caloric intake
• Achieve physical fitness by including
• cardiovascular conditioning,
• stretching exercises for flexibility, and
• resistance exercises or calisthenics for muscle
strength and endurance.
Food Groups to Encourage
• Sufficient amount of fruits and vegetables while staying
within energy needs (recommended for a reference 2000-calorie
• Selections from all five vegetable subgroups several
times a week
• Daily:
• Variety of fruits and vegetables
• At least 3 ounces of equivalents of whole-grain products with
the rest of the recommended grains from enriched or wholegrain products
• 3 cups per day of fat-free or low-fat milk or equivalent milk
Carbohydrates (CHOs)
• Select fiber-rich fruits, vegetables, and whole
• Select foods and beverages with little added
sugar or caloric sweeteners.
• Limit consumption of sugar- and starchcontaining foods and beverages.
Sodium and Potassium
• Consume less than 2,300 mg (approx. 1 tsp. of salt) of
sodium per day.
• Choose and prepare foods with little salt.
• Consume potassium-rich foods such as fruits and
Alcoholic Beverages
• Those who drink should practice responsible drinking:
one or fewer drinks per day for women and two or
fewer drinks per day for men.
• Alcohol consumption should be completely avoided in
many situations where the individual cannot control
their consumption (ex. Pregnancy, Rx’s)
Well-Balanced Nutrition
• The Institute of Medicine [IOM], (2002), recommends
following percentage contribution, by food group, for a wellbalanced nutritional plan for adults:
• 45% to 65% of their calories from CHOs
• 20% to 35% of their calories from fat
• 10% to 25% of their calories from protein
• Since 1971, the average daily energy intake increased ≈7% for
men and 21% for women. This increase in calorie intake was
attributed primarily to increases in the relative and absolute
carbohydrate intake. The relative carbohydrate intake
increased from 42% to 49% in men and from 45% to 51.6% in
• Also, the relative dietary fat increase for men and women was
between 5 and 7 g/day, and dietary protein slightly decreased.
• Major types:
• Simple CHOs: simple sugars found in fruits, berries, some
vegetables, table sugar, and honey
• Complex CHOs: found in many plant-based foods, whole grains,
and low-fat dairy products
• Experts tout health benefits of consuming wide range of
CHOs with emphasis on fruits, vegetables, whole grains, and
low-fat dairy products.
• To maintain and replenish glycogen stores, you need a daily
CHO intake of
• 7 to 8 g·kg–1 of body weight if you engage in low-intensity,
moderate-duration physical activity.
• 7 to 12 g·kg–1 of body weight if you engage in high-intensity or
long-duration exercise.
• The glycemic index (GI) has been used to classify
carbohydrate-containing foods.
• The GI is a measure of the body’s glycemic response (i.e.,
increase in blood glucose and insulin following consumption)
to various foods.
• To obtain the GI value of a food, the glycemic response of that
food is compared with the glycemic response of glucose (GI =
• Generally, refined grain products and potatoes have a high GI
(>60), legumes and unprocessed grains have a moderate GI
(40-60), and non-starchy fruits and vegetables have a low GI
• The AHA, American Diabetes Association, and American
Dietetic Association do not endorse using the GI for disease
prevention and treatment
• Approximately 10% to 25% of the daily caloric intake should
be protein.
• The diet should include sources of the essential amino acids
needed for protein synthesis.≈≈
• In general, daily protein requirement of the body is ≈ 0.8
g·kg–1 of body weight.
• For endurance athletes recommended intake is 1.2 to 1.4
g·kg–1 of body weight.
• Strength-trained athletes may need as much as 1.7 g·kg–1 of
body weight.
• Too much protein in the diet causes dehydration due to
excessive production of urea, which must be eliminated in
the urine
• Some dietary fat is needed to supply fatty acids and to
absorb fat-soluble vitamins.
• Approximately 20% to 35% of the daily energy intake
should come from fat; however, fats must be chosen
• To promote weight loss and to reduce serum
cholesterol level, limit these intakes:
• saturated fat and trans fatty acids (<7% of total
• total fat (25% to 35% of total calories)
• cholesterol (<200 mg per day if one has elevated
LDL; otherwise < 300 mg/day)
• No need to supplement if diet is balanced.
• Those restricting food intake to lose weight
or make weight, may benefit from
• Supplementation is beneficial only for
those who are deficient in one or more
• See also Table 9.5, p. 242
• Physically active individuals, particularly
vegetarians, may need to supplement iron and
• Iron requirements for endurance athletes (e.g.,
distance runners) are increased by 70% (ACSM
• For athletes with eating disorders, amenorrhea,
and risk for early osteoporosis, 1,500 mg of
elemental calcium and 400-800 IU of vitamin D
per day are recommended (ACSM 2009).
Vitamin and Mineral
Supplementation Facts
• Vitamin B12 supplementation does not increase
muscle growth or strength.
• Carnitine (a vitamin-like compound)
supplementation does not facilitate loss of body
• Chromium supplementation does not increase
fat-free mass or decrease body fat.
• Boron supplementation does not increase serum
testosterone or fat-free mass.
• Magnesium supplementation does not improve
muscle strength.
• Athletes and physically active individuals need to
• hydrate before exercise,
• drink fluids during exercise, and
• rehydrate immediately after exercise.
• The amount and rate of fluid replacement depend
on the athlete’s sweat rate, exercise duration, and
opportunities to drink.
• Guidelines for maintaining hydration before, during,
and after exercise have been developed by the
ACSM and the National Athletic Trainers’
Association (next slide)
Prehydration, Hydration, and
• Guidelines for hydration:
• About 4 hours before exercise, drink 5 to 7 ml/kg of
body weight of water or a sport beverage.
• Replace fluids depending on sweat rate, exercise
duration, and opportunities to drink.
• Drink at least 6 ounces of fluid every 15 to 20 minutes.
• Consume drinks containing CHO (6-8%) and sodium
when endurance exercise is more than 1 hour.
• Drink at least 16 ounces of fluid for every pound of
body weight lost during exercise.
Designing Weight-Management
Programs: Preliminary Steps
In designing weight management programs for weight
loss or weight gain, you need to set body weight goals
and assess the calorie intake and expenditure for your
1. Set body weight goals.
2. Assess calorie intake and energy expenditure.
3. Design weight-loss program inclusive of caloric
restriction plus exercise program.
4. Work closely with a licensed nutritionist or
registered dietitian when planning diets for your
clients. (See example of process, next slides , pp. 251-2.)
Steps for Designing a Weight
Loss Program
Steps for Designing a Weight
Loss Program
Weight-Loss Diets
• Low-carbohydrate (carb) iso-caloric diets (e.g.,
Atkins) result in rapid short-term weight loss in
obese adults; shown to improve triglyceride
and HDL-C levels.
• High-protein or low-carb diets result in great
3- to 6-month weight losses; high-protein diets
increase satiety and may thereby reduce daily
caloric intake.
• Long-term effect of macronutrient restrictive
diets is not yet known.
Weight-Loss Diets (continued)
• Research shows that weight loss depends on calorie
intake and not on the macronutrient composition of the
• An effective strategy for reducing energy (calorie) intake
is to eat less refined, processed food as well as less
saturated and trans fat.
• A balanced diet contains adequate amounts of good
sources of carbohydrate, protein, and fat (table 9.8).
• Healthy Eating Pyramid: (figure 9.2)
• Foundation of daily physical activity and weight control
• Recommendations for food choices that promote health and
weight control
Exercise for Weight Loss
• For health benefits according to ACSM (2008):
• At least 30 minutes of moderate-intensity (3-6 METs) activity
at least 5 days a week or
• 20 minutes of vigorous-intensity (>6.0 METs) for a minimum of
3 days a week
• Alternatively, according to the 2008 Physical Activity Guidelines
for Americans, health benefits are achieved with
• 150 to 300 minutes a week of moderate-intensity (3-6 METs)
exercise or
• 75 to 150 minutes a week of vigorous-intensity (≥ 6.0 METs)
Exercise for Weight Loss (for
summary see Table 9.9, next slide)
• Preventing weight gain:
• Moderate-intensity physical activity between 150 and 250
minutes a week (ACSM 2009)
• 45 to 60 minutes of moderate- to vigorous-intensity activity on
most, preferably all, days (IOM, 2002)
• For children and adolescents, at least 60 minutes of moderateto vigorous-intensity physical activity daily
• Specific amount of physical activity needed to prevent weight
regain is uncertain.
• About 60 minutes a day of walking at a moderate intensity is
associated with weight maintenance (ACSM 2009).
• At least 60 minutes, but preferably 80 to 90 minutes, of moderateintensity physical activity and exercise recommended per day (IOM
Table 9.9
Benefits of Exercise in Weight
• Increases energy expenditure
• Helps create a negative energy balance for
weight loss
• Promotes fat loss and preservation of LBM
• Maintains or slows down FFM loss resulting
from weight loss via diets only
• Helps maintain weight loss after dieting
• Increases RMR
Types of Exercise in Weight
• Aerobic exercise is effective for weight loss, fat
loss, and long-term weight management.
• Resistance training increases muscle mass and
REE; it does not produce much weight loss.
• Resistance training may increase fat loss when
combined with aerobic exercise.
Exercise Intensity and Weight
• Weight loss and fat loss are positively related
to weekly energy expenditure.
• At a constant energy expenditure, total fat
oxidation is higher during low-intensity
compared to high-intensity exercise.
• Exercise duration may be key for fat loss.
• Most obese clients prefer a slower pace and
low- to moderate-intensity exercise.
Designing Weight-Gain
• First, rule out the possibility that diseases and
psychological disorders associated with malnutrition are
causing low weight level.
• A caloric excess of 2,800 to 3,500 kcal is required to gain
1 pound.
• Adding 400 to 500 kcal to the estimated daily caloric
needs can result in a gain of 1 pound a week.
• Adjust caloric intake to cover exercise energy
Exercise Prescription for
Weight Gain
• Prescribe resistance training to increase muscle
• A high-volume resistance training program
maximizes muscle size best.
• Novice weightlifters should start slowly.
• See text for recommended guidelines for
developing an exercise prescription for weight
Designing Programs to
Improve Body Composition
• You can decrease subcutaneous fat, fat weight, and percent
body fat of adults with aerobic and resistance exercise.
• No type of aerobic exercise training is better than another
for fat loss.
• Frequency of 4 days a week is found to be superior to 3 days
a week.
• Combining aerobic and resistance training exercises
produces effective change in body composition of nondieting individuals.
End of Presentation