1. Obesity: Pathophysiology, And
Risk Assessment
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2. • Obesity:
• Excessive amount of body fat.
– Women with > 35% body fat.
– Men with > 25% body fat.
• Increased risk for health problems.
• Are usually overweight, but can have healthy
Body Mass Index(BMI) and high % fat.
• BMI =weight kilograms / height meters2
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3. • Desirable % Body Fat:
• Men: 8-25%.
• Women 20-35%.
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4. • Regional Distribution:
• The regional distribution of body fat affects
risk factors for the heart disease and type 2
diabetes.
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5. • Body Fat Distribution: Gynoid
• Lower-body obesity--Pear shape.
• Encouraged by estrogen and progesterone.
• Less health risk than upper-body obesity.
• After menopause, upper-body obesity
appears.
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6. • Body Fat Distribution: Android
• Upper-body obesity--apple shape.
• Associated with more heart
disease, Hypertensiion(HTN), Type II Diabetes.
• Abdominal fat is released right into the liver.
• Encouraged by testosterone and excessive
alcohol intake.
• Defined as waist measurement of > 40” for
men and >35” for women.
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7. • Body Fat Distribution:
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8. • Weight Management:
• Balancing energy intake and
energy expenditure is the
basis of weight management
throughout life.
• Dieting and physical exercise.
• Orlistat (Xenical) medication
to treat obesity.
• In severe cases, bariatric
surgery is performed or an
intragastric balloon is placed
to reduce stomach volume.
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9. Pathophysiology
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10. • Role of Brain Neurotransmitters:
• Neurotransmitters govern the body’s response
to starvation and dietary intake.
• Decreases in serotonin and increases in
neuropeptide Y are associated with an
increase in carbohydrate appetite.
• Neuropeptide Y increases during deprivation;
may account for increase in appetite after
dieting.
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11. • Hormonal Regulation of Body Weight:
• Norepinephrine and dopamine—released by
sympathetic nervous system in response to
dietary intake.
• Fasting and semistarvation lead to decreased
levels of these neurotransmitters—more
epinephrine is made and substrate is
mobilized.
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12. • Hormones And Weight:
• Leptin is produced by adipose tissue to signal
fat storage reserves in the body, and mediates
long-term appetitive controls (i.e. to eat more
when fat storages are low and less when fat
storages are high).
• Ghrelin produced by the stomach modulating
short-term appetitive control (i.e. to eat when
the stomach is empty and to stop when the
stomach is stretched)
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13. 2/13/2012 13

14. • Hunger vs. Satiety:
• Satiety—postprandial state when excess food
is being stored.
• Hunger—postabsorptive state when stores are
being mobilized.
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15. • Hunger vs. Satiety—contd:
• Feedback mechanism with signal from adipose
mass when weight loss occurs—eating is the
natural result.
• Not always identified in the elderly.
• This occurs mostly in young people.
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16. • Causes of Obesity:
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17. • Causes of Excessive Energy Intake:
• Active: large portion sizes, frequent meals and
snacks.
• Passive: excessive intake of energy-dense
foods containing hidden calories.
• Variety of options: the greater the variety of
foods offered, the greater the intake.
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18. • Low Energy Expenditure:
• Sedentary lifestyle.
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19. • Genetics:
• Identical twins have similar weights.
• Genes affect metabolic rate, fuel use, brain
chemistry, body shape.
• The thrifty gene hypothesis postulates that
due to dietary scarcity during human
evolution people are prone to obesity.
• Thrifty metabolism gene allows for more fat
storage to protect against famine.
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20. Genetics:
Obesity tends to run in families.
• If both parents are normal weight – 10%
chance of obesity in offspring.
• If one parent is obese – 40% chance.
• If both parents obese – 80% chance.
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21. • Environmental factors influence weight:
• Overeating learned early in childhood.
• Urging children to eat more, clean their plates.
• Use of food as a reward.
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22. • Medical and psychiatric illness:
• Physical and mental illnesses and the
pharmaceutical substances.
• Hypothyroidism, Cushing’s syndrome, growth
hormone deficiency, and the eating disorders:
Binge eating disorder and Night eating syndrome.
• Insulin, sulfonylureas, thiazolidinediones, atypical
antipsychotics, antidepressants, steroids, certain
anticonvulsants (phenytoin and valproate), and
some hormonal contraception.
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23. • Obesity is a Growing Problem:
• 127 million adults in the U.S. are
overweight, 60 million obese, and 9 million
severely obese.
• 66 percent of U.S. adults are overweight
(BMI≥25).
• 32 percent are obese (BMI≥30).
• 17% of children and adolescents ages 2-19 are
overweight.
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24. • Obesity: A Major Health Issue:
• Obesity is the SECOND preventable cause of
death and disability (smoking is #1).
• Obesity is associated with increased risk of
heart disease, stroke, gallbladder
disease, cancer, osteoarthritis, sleep apnea.
• Obesity-related health problems cost $75
billion annually (2003 data).
• The public pays about $39 billion a year -- or
about $175 per person -- for obesity through
Medicare and Medicaid programs.
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25. • Health Problems Associated with Excess Body
Fat: • Type 2 diabetes
• Surgical risk
• Gallstones
• Lung (pulmonary)
disease
• Cancers
(breast, colon, pa
• Sleep apnea
ncreas, gallbladde
• HTN r)
• CVD
• Infertility
• Bone and joint
• Pregnancy-
disorders
(gout, osteoarthrit difficult delivery
is)
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• Reduced agility 25

26. • Metabolic Syndrome Criteria*:
Three or more of the following abnormalities:
• Waist circumference >102 cm (40 inches) in
men and > 88 cm (35 inches) in women.
• Serum triglycerides of at least 150 mg/dL.
• High density lipoprotein level <40 mg/dL in
men and <50 mg/dl in women.
• Blood pressure >=135/85 mm hg.
• Serum glucose >=110 mg/dl.
–*Adult Treatment Panel (ATP) III Guidelines.
National Cholesterol Education Program, 2001.
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27. • Polycystic Ovary Syndrome (PCOS):
• Endocrine disorder characterized by
hyperandrogenism and insulin resistance.
• Associated with android obesity.
• Affects 5-10% of reproductive age women.
• Erratic menstrual periods, chronic
anovulations resulting in multiple ovarian
cysts; infertility, acne, hirsutism and alopecia.
• Increased risk of heart disease, type 2
diabetes, reproductive cancers.
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28. • Management of PCOS:
• Symptom oriented, as etiology is unclear.
• Individualized diet and exercise plan to
promote weight loss and normalize insulin
levels.
• Medications to alleviate symptoms.
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29. • BMI and Health:
Below 18.5 Underweight
18.5 – 24.9 Normal
25.0 – 29.9 Overweight
Monitor for risk
30.0 and Above Obese
Increased health risk
40.0 and above Severely obese
Major health risk
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30. • REFERENCE:
• Internet: http://medicalppt.blogspot.com
• en.wikipedia.org
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