ObesityPresented 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