Obesity
Presented by Kristen Billings
What is Obesity?
 Surplus of adipose tissue-containing fat stored in
triglyceride form
 Characterized by excess body weight
 Overweight is defined as deviation in body weight from
some standard or “ideal” weight related to height.
 Body weight is a function of energy balance over an
extended period of time
 Overweight does not always reflect obesity
 The point at which excessive fat constitutes obesity is
arbitrary
Epidemiology
 Accessible, abundant, and inexpensive energy-dense
foods among industrialized countries
 Substantial reduction in average daily energy
expenditure required for survival.
 Evolutionary adaptation theory
 More than two decades of steadily increasing rates of
obesity
 Since the end of 2006 the rates have appeared to stabilize
Epidemiology
 66% are overweight, 5% extremely obese
 18% of children are overweight
 In 2006- 33.3% of adult men and 35.3% women in U.S were
categorized as obese (BMI > 30)
 Notably higher raters of obesity were seen in Hispanic and
non-Hispanic black women.
Cost
 Obesity related conditions account for 7% of total
healthcare costs in the U.S.
 Direct and indirect costs of obesity are in excess of $117
billion annually
Symptoms
 BMI (weight in kg/height squared in meters):
 Class I 30.0-34.9
 Class II 35.0-39.9
 Class III >40.0
 Excessive accumulation of body fat
 Women >35%
 Men >25%
Diagnosis
 Body Mass Index
 Waist Circumference
 Body Fat Percentages
 Waist to hip ratio
Complications
 Associated with numerous comorbidities, many of which
are life threatening
 Increases the overall risk and severity of numerous
diseases
 Altered physiological responses: increased fasting insulin,
increased insulin response to glucose, decreased insulin
sensitivity, decreased growth hormone, decreased
growth hormone response to insulin stimulation, increased
adrenocortical hormones, increased cholesterol synthesis
and excretion, decreased hormone-sensitive lipase
Complications
 Distribution of fat is of more importance for risk of disease
than total fat alone
 Upper body fat distribution (android obesity): strongly
correlated with increased risk of coronary artery disease,
hypertension, hyperlipidemia, diabetes, hormone and
menstrual dysfunction
Complications
 Chronic Diseases
 Diabetes
 Hypertension
 Hypercholesterolemia
 Hyperinsulinemia
 Hypertriglyceridemia
Increased risk of
cardiovascular
disease
Treatment
 Primary objective of obesity management is to reduce
fat weight while preserving lean body weight
 Behavioral change focused on dietary and activity
habits toward weight reduction
 FDA approved drugs
 FDA approved invasive procedures
Treatment- Behavioral Change
 Patients are less motivated by health and more by
personal appearance
 Success in weight loss is more commonly seen when:
 Person is slightly or moderately obese
 Has upper body fat distribution
 Doesn’t have a history of weight cycling
 Sincere desire to lose weight
 Became overweight as an adult
Treatment- Drugs
Drug
Mechanism of action
Exercise-related
precautions
Adipex-P
Appetite suppressant
Increase in blood
pressure
Meridia
Appetite suppressant
Increase in blood
pressure
Dexedrine
CNS stimulant
Possible cardiovascular
risks
Alli & Xenical
Reduction in fat
absorption via inhibition
of pancreatic lipase
activity in intestine
none
Treatment- Invasive Procedures
 Based on reducing the size of stomach and lowering the
absorption of nutrients in the intestine
 Must have BMI of >40 or >35 with comorbidities such as
diabetes and hypertension to be eligible
 Surgical treatment of obesity has been shown to reduce
excess body weight by an average of 50-60%
Treatment- Invasive Procedures
 Laparoscopic gastric banding
 Minimally invasive surgery
 Adjustable silicone band is placed around top portion of
stomach
 Small gastric pouch is created which reduces capacity of
stomach and produces a feeling of fullness shortly after
eating
 Benefits: minimal surgical trauma and pain, fast recovery
rate, rare operative mortality.
Surgery Videos
 http://www.youtube.com/watch?v=n-ucSHx9nHM
 http://www.youtube.com/watch?v=P83Vs9GQ0WI
Treatment- Invasive Procedures
 Roux-en-Y gastric bypass
 Invasive surgical procedure that reduces capacity of the
stomach
 A small pouch is created at the top of the stomach that is
then connected directly to middle portion of the small
intestine
 The rest of the stomach and the upper portion of the small
intestine are bypassed.
 Procedure has a higher mortality and complication risk than
the lap-band
Effects of Exercise
Biomechanical Effects
 Excess joint stress
 Affected movement and gait
 Increased foot pressure
 Decreased strength
 Increased risk of osteoarthritis
 http://www.youtube.com/watch?v=cNATWsVVwgo
Effects of Exercise
 Comorbidities of obesity (diabetes, hypertension, CAD,
sleep apnea, increased overall risk of exercise) may
affect the exercise response.
 Past experiences/current fears of exercise
 Exercise training in combination with caloric restriction
reduces body weight and favorably alters body
composition.
 Ineffective in morbidly obese individuals
Benefits of Exercise
 Preservation of lean body mass despite caloric restriction
 Improved insulin sensitivity
 Favorable changes in metabolic rate and lipid profiles
 Reduced blood pressure
 Improved mood
 Possible effects on satiety
 Overall reduction in comorbidity risk
Benefits of Exercise
 Loss of regional fat
 More effective in reducing abdominal fat cell size than
diet alone
 Energy expenditure following exercise remains elevated
above pre-exercise levels
 Glucose metabolism
 Decreased fasting glucose and insulin
 Increased glucose tolerance
 Decreased insulin resistance
Exercise Testing
 Primary goal: develop a safe and effective exercise
program
 Low-level protocols are recommended because of the
low function capacity of most obese individuals
 Testing protocol must take into consideration any
comorbidities, orthopedic limitations and current
medications.
 Arm or leg ergometry may be more appropriate
depending on orthopedic limitations and weight limits of
treadmills.
Exercise Testing
 Initial exercise intensity is most likely far below the point at
which cardiac risk is of concern
 Exercise testing is used to determine physical work
capacity
Special Considerations
 Increased risk of orthopedic injury
 Physical injury may be primary reason for discontinuation of
exercise
 Increased risk of cardiovascular disease
 Increased risk of heat intolerance
 Weight regain averages 33-50% of initial weight loss within
1 year of terminating treatment
Exercise Prescription
 Exercise prescription should optimize energy expenditure
while maintaining minimal potential for injury
 Total energy expenditure should include that of the
actual exercise as well as the recovery period
 Two or more short sessions/day may be more tolerable
and result in same or higher total energy expenditure
Exercise Prescription
 ACSM recommends accumulating 200-300 min/week
(>2000 kcal/week) of physical activity for weight loss and
weight maintenance.
 Initial intensity and duration should be low and
progression should be gradual:
 Mode- non-weight-bearing exercise such as: walking,
swimming, biking increase in activities of daily living and
resistance training
 Frequency-daily or at least 5/week
 Duration- 200-300 min/wk (30-60 min/day)
 Intensity- 40-60% of peak oxygen consumption
Exercise Goals
 Significant health benefits can be achieved by losing
only 10-20% of body weight even if the ideal body weight
is not reached
 Loss of 1lb/week, -3500 calories/week, -500 calories/day
 Loss of 10lbs maintained for 6 months before further
weight loss
Summary and Conclusion
 Overuse injury prevention
 Adequate flexibility, warm-up, cool-down
 Gradual progression of intensity and duration
 Use of low-impact or non-weight-bearing exercises
 Thermoregulation
 Neutral temperature and humidity
 Cool times of day
 Adequate hydration
 Loose fitting clothing
References
1.American College of Sports Medicine. 2010. ACSM’s guidelines for exercise testing
and prescription, 8th ed. Baltimore: Lippincott Williams & Wilkens, chapter 10.
2.ACSM. 1999. Roundtable Supplement. Physical activity in the prevention and
treatment of obesity and its comorbitities. Med. Sci. Sport Exer. 31(11) : S497-S667.
3. American Obesity Association. 2000. http://www.obesity.org/
4.ACSM. 2009. Position Stand. Appropriate physical activity intervention strategies
for weight loss and prevention of weight gain for adults. Med. Sci. Sport Exer. 41
:459-467.
5.Rampersaud, E., et al. 2008. Physical activity and the association of the common
FTO gene variants with body mass index and obesity. Arch Intern Med. 168(160):
1791-1797.
6. Patricia Curtis. 2007. Fighting Fat New Frontiers. Readers Digest. 85-91