3. HISTORICAL ASPECTS
Hippocrates is reported to have
said “sudden death is more common
in those who are fat than in the lean”
The greeks were the first to
recognize obesity as a medical
disorder Hippocrates wrote that
‘corpulence is not only a disease
itself,but the harbinger of others”
During the Middle Ages obesity
was often seen as a sign of wealth,
and was relatively common among
the elite
4. OBESITY
Overweight and obesity are terms used to describe
individuals with an increased body fat, a certain
amount of body fat is necessary for storing energy,
heat insulation ,shock absorption,and other
functions
Measuring fat accurately in human requires special
equipments and so usually excess weight is defined
by measuring the body mass index (BMI)
BMI is calculated by measuring a person’s weight in
KG divided by that person’s height in meters
squared (kg/m²) .for example an adult weighing 90
kg with a height of 1.8 m has a BMI of 27.8
5. • The internationally accepted classification
of BMI in adults is as follows
BMI Classification
< 18.5 underweight
18.5–24.9 normal weight
25.0–29.9 overweight
30.0–34.9 class I obesity
35.0–39.9 class II obesity
≥ 40.0 morbid obesity
6.
7. AETIOLOGY OF OBESITY
1-FAMILIAL & GENETIC PREDISPOSITION
• There is a number of known genetic
conditions which produce a syndrome
complex associated with obesity
• The best known is the prader-willi syndrome
which is associated with deletions on
chromosome 15 resulting in excessive appetite
• The contribution to weight gain of
transmission in susceptable families ranges
from 25-40% ,this transmission is derived
from both maternal & paternal lines
10. 4-AGE
Weight increases with age at least up to 60
years
5-GENDER
Women have a higher prevalence of excess
weight than men
6-FAT INTAKE
prevalence is higher in those with high fat intake
11. 7-SMOKING CESSATION
• Cessation of smoking increases weight ,the
average weight gain is 2.8 kg in males & 3.8
in females
8-PHYSICAL ACTIVITY
Declining physical activity predisposes to
weight gain such as sedentary jobs and
certain pastimes e.g. watching television
and computer games
12. Body fat percentage
• Body fat percentage can be estimated from a
person's BMI by the following formula:
• Body fat % = 1.2(BMI)+0.23(age)-5.4-
10.8(gender)
where gender is 0 if female and 1 if male This
formula takes into account the fact that body
fat percentage tends to be 10 % greater in
women than in men for a given BMI. It
recognizes that a person's percentage body fat
tends to increase as they age, even if their
weight and BMI remain constant.
13. Cross-sections of the torso of a person of normal weight
(left) and an obese person (right), taken by CT scan. Note
the 3.6 cm of subcutaneous fat on the obese person.
14.
15. Pathophysiology of Obesity
Genetics vs. Environment
• The relative contributions of genetics and environment to the
etiology of obesity have been evaluated in many studies, 30% to
40% of the variance in BMI can be attributed to genetics and
60% to 70% to environment.
• The interaction between genetics and environment is also
important. In a given population, some people are genetically
predisposed to develop obesity, but that genotype may be
expressed only under certain adverse environmental
conditions, such as high-fat diets and sedentary lifestyles .In
the United States, as well as in other Western countries,
greater numbers of people are being exposed to these adverse
environmental conditions, and consequently, the percentage of
people expressing the obesity genotype has increased.
16. • the possible pathophysiological mechanisms
involved in the development and maintenance
of obesity.
• This field of research had been almost
unapproached until LEPTIN was discovered in
1994. Since this discovery, many other
hormonal mechanisms have been elucidated
that participate in the regulation of appetite
and food intake, storage patterns of adipose
tissue, and development of insulin resistance.
17. • Leptin and ghrelin are considered to be
complementary in their influence on appetite,
with 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).
• 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).
18. • While leptin and ghrelin are produced peripherally, they control appetite through their
actions on the central nervous system In particular, they and other appetite-related
hormones act on the hypothalamus,.
• There are several circuits within the hypothalamus that contribute to its role in
integrating appetite, the melanocortin pathway being the most well understood.[
The
circuit begins with an area of the hypothalamus, the arcuate nucleus, that has outputs
to the lateral hypothalamus (LH) and ventromedial hypothalamus(VMH), the brain's
feeding and satiety centers, respectively.
• The arcuate nucleus contains two distinct groups of neurons. The first group
neuropeptide Y (NPY) (AgRP) and has stimulatory inputs to the LH and inhibitory
inputs to the VMH. The second group pro-opiomelanocortin(POMC) and cocaine- and
amphetamine-regulated transcript(CART) and has stimulatory inputs to the VMH and
inhibitory inputs to the LH. Consequently, NPY/AgRP neurons stimulate feeding and
inhibit satiety, while POMC/CART neurons stimulate satiety and inhibit feeding.
• Both groups of arcuate nucleus neurons are regulated in part by leptin. Leptin inhibits
the NPY/AgRP group while stimulating the POMC/CART group. Thus a deficiency in
leptin signaling, either via leptin deficiency or leptin resistance, leads to overfeeding
and may account for some genetic and acquired forms of obesity.[
19. A comparison of a mouse unable to produce leptin
thus resulting in obesity (left) and a normal mouse
(right)
20. Metabolic Predictors of Weight Gain
The development of obesity occurs when the
caloric intake is disproportionate to the energy
expended.
Three metabolic factors have been reported to be
predictive of weight gain:
- low adjusted sedentary energy expenditure,
- high respiratory quotient (RQ; carbohydrate-to-
fat oxidation ratio), and
- low level of spontaneous physical activity
21. • The resting metabolic rate (RMR) is
strongly correlated to fat-free mass (FFM)
in both men and women . However, RMR is
only one component of the total daily
energy expenditure, which also includes
the thermic effect of food and physical
activity .
22. • RQ is the second potential metabolic
predictor of weight gain. A low RQ of 0.7
suggests that a person is oxidizing more fat
than carbohydrate, whereas a ratio of 1.0
suggests that more carbohydrate than fat is
being oxidized
23. Patterns of Body-Fat Distribution
GYNOID DISTRIBUTION
• Fat stored mainly around the hips and
thighs and this is characteristic of women
ANDROID DISTRIBUTION
• Storage of fat primarily in the abdomen
producing abdominal obesity
24.
25. TO CHECK FOR ABDOMINAL OBESITY
WAIST CIRCUMFERANCE
• Waist circumference is measured halfway
between the superior iliac creast and the
rib cage in the
High Risk
• Men > 102 cm
• Women > 88 cm
27. • WAIST-HIP RATIO (WHR)
This ratio is derived from measuring the waist
circumference divided by the hip
circumference ,both in centimeters
The hip circumference is measured one-third of
the distance between the superior iliac spine
and the patella
Abdominal obesity is a risk to health if the WHR
is >0.95 in males or >0.8 in females
28. Health risks Associated with
Obesity
Mortality
• Obesity is one of the leading preventable causes of
death worldwide.Large-scale American and
European studies have found that mortality risk is
lowest at a BMI of 20–25 kg/m2
A BMI above 32 has
been associated with a doubled mortality rate
• On average, obesity reduces life expectancy by six
to seven years, a BMI of 30–35 reduces life
expectancy by two to four years, while severe
obesity (BMI > 40) reduces life expectancy by
10 years.
29. Type 2 Diabetes
• The relative risk of developing type 2 diabetes increases
steeply with increasing BMI. This relationship is best
demonstrated by the Nurses' Health Study, which
prospectively followed up more than 114,000 registered
nurses for 14 years . Women with BMI of 35 kg/m2
or
greater had a 93 times higher risk of developing
diabetes than those with BMI of <22 kg/m2
.
• Even women who were overweight had higher risk;
those with BMI of 25.0 to 26.9 kg/m2
and 27.0 to 28.9
kg/m2
had relative risks of 8.1 and 15.8, respectively.
• Abdominal obesity, as measured by waist-to-hip ratio,
may be a stronger predictor of diabetes than BMI alone
30. CHD
A relationship between obesity and CHD mortality was
demonstrated in the Nurses' Health Study . The relative risk of
CHD death increased significantly with increasing BMI
Women with BMI of 29.0 to 31.9 kg/m2
and 32.0 kg/m2
or higher
were at 4.6 and 5.8 times greater risk, respectively, than those
with BMI values under 22.0 kg/m2
. Moreover, the waist-to-hip
ratio was strongly predictive of CHD mortality.
Women in the highest quintile of waist-to-hip ratio had a
relative risk of CHD death of 8.7 compared with those in the
lowest quintile.
31. Hypertension
• The risk of hypertension also increases with increasing
BMI.
• The hypertension associated with obesity is
characterized by an increase in vascular volume,
whereas peripheral resistance is generally borderline or
only slightly elevated .
• Several mechanisms may be involved in the
development of hypertension in obese subjects:
increased renal sodium and water absorption,
sympathetic nervous system activation, changes in
Na+
/H+
-ATPase activity, and growth factor–mediated
structural changes to the vascular wall. In each case,
hyperinsulinemia may be a contributing factor.
32. CHRONIC ABDOMINAL COMPARTMENTATION SYNDROME
• Abdominal obesity espcially in the morbid obese
individual can result in chronic abdominal
compartmentation syndrome
• It is thought that the mass of omental fat increases
intra-abdominal pressure resulting in stress
incontinence as well as increased gastric acid reflux
• The tenting of the diaphragm can increase intra-
thoracic pressure raising right atrial pressure with
associated pulmonary hypertention and subsequent
breathlessness
33. Dyslipidemia
• Impaired glucose use and increased hepatic glucose output are
not the only consequences of the higher FFA levels in obesity.
Increased FFAs also affect lipid metabolism by increasing very-
low-density lipoprotein production by the liver, reducing high
density lipoprotein (HDL)-cholesterol levels, and increasing
the number of small, dense low-density lipoprotein (LDL)
particles . These smaller particles are better able to penetrate
the arterial wall, more readily undergo oxidation and glycation,
and are more atherogenic than larger, LDL particles. Even
when the LDL cholesterol level does not change appreciably,
atherogenic risk may be higher because of the presence of the
smaller LDL particles. Taken together, these changes in
lipoprotein profile are associated with increased risk of CHD.
34. Bone and cartilage degeneration (Osteoarthritis)
Obesity is an important risk factor for
osteoarthritis in most joints, especially at the
knee joint (the most important site for
osteoarthritis). Obesity confers a nine times
increased risk in knee joint osteoarthritis in
women. Osteoarthritis risk is also linked to
obesity for other joints.
Data suggest that metabolic and mechanical
factors mediate the effects of obesity on joints
(University of Bristol).
35.
36. liver
• Fatty infiltration of the liver
• In morbidly obese with BMI greater than
40 only 2% have normal livers , 56% shows
fatty infiltration and 42% have fatty
infiltration associated with fibrosis or
cirrhosis
37. Gallbladder Disease
Is the most common form of digestive
disease in obese individuals
There is a progressive linear increased risk
of gallstones from a BMI of 20 upwards
Weight loss may actually exacerbate gall
bladder disease this may be caused by the
rise in the circulating cholesterol as
adipose tissue stores are mobilized and
increase in the rate of cholesterol
excreated in bile
38. PREGNANCY
• Increased risk of developing gestational
diabetes
• Increased risk for pregnancy induced
hypertention
• Increased risk for urinary tract infection
Other complications include:
Pre-eclampsia,thrombophlebitis,post-partum
haemorrhage,wound infection
39. Obese women have an increased risk of caeserean
delivery owing to a variety of factors including:
Fetal size
An increase in maternal pelvic soft tissue narrowing
the birth canal
Prolonged labour
Malpresentations
Recently ,an inrcreased risk of neural tube defects
especially spina bifida ,has been reported in women
with BMI greater than 29
40. RHEOLOGY
• A number of haemostatic factors is associated
with weight gain , particularly factors
which may relate to thrombosis and the risk
of fatal myocardial infarction
• A 15% weight loss is associated with a decrease
in blood viscosity by 20% and in haematocrite
by 5.5% wheras plasma fibrinogen remains
unaffected
41. Cancer
• The impact of obesity on cancer mortality was evaluated
prospectively in a study of 750,000 men and women who were
followed for 12 years . Men and women who were at least 40%
overweight were 33% and 55% more likely, respectively, to die
from cancer than those of average weight. Specifically, the
mortality ratios for colorectal and prostate cancer in men and
endometrial, uterine, cervical, ovarian, gallbladder, and breast
cancer in women were highest among those who were at least
40% overweight.
• Similarly, in the Nurses' Health Study, cancer mortality
increased with increasing BMI . The cancer death rate for
women with BMI of 32 kg/m2
was twice that for women with
BMI of less than 19 kg/m2
.
42. Breast cancer
Age has a significant impact on the risk of
developing breast cancer
Pre-menopausal obese women have the same risk as
lean women ,but post menopausal women
exhibit a higher risk
Abdominal obesity and a positive family history
increase this risk
Central adiposity is associated with enhanced
conversion of androgens to oestrogen in the fat
mass and a reduced sex – hormone – binding
globulin (SHBG) which adds to an increase in
free oestradiol levels
43. MEDICAL MANAGEMENT OF OBESITY
The medical management of weight can be
considered in four approaches based on the
most recent advice given by the Royal
college of physicians in scotland and
england
1-Weight reduction
2-weight maintenance plan
3-drug therapy
4-very –low-calorie diets
44. 1-Weight reduction
This aims to provide a 3-month management plan designed
specifically to the needs of each individual patient
This comprises:
A-a moderate reduction in energy intake of about 600 cal. ,this
produces a greater weight loss than more strict diets due to
improved compliance
B-behavioural modification therapy which is designed to support
a process of change in the individual’s attitude regards food
intake ,life style and physical activity
C-promotion of increased physical activity : walking briskly for 30
minutes each day can contribute to 200 cal. Of energy
expenditure daily resulting in an additional weight loss of 1
kg. /month
45. Dietary changes
• The Mayo Clinic advises obese people to reduce
their total daily calorie intake and to consume
more fruits, vegetables and whole grains.
• It is important that your diet is varied - you still
continue to enjoy the tastes of different foods.
The consumption of sugar, certain refined
carbohydrates and some fats should be reduced
significantly.
Behavioural changes including advice nt to snack
between meals ,not to buy excess food, and not to
eat while feeling depressed
46. Physical activity
• The more you move your body the more
calories you burn.
• To lose a kilogram of fat you need to burn
8,000 calories .
• Walking briskly is a good way to start
increasing your physical activity if you are
obese. Combining increased physical activity
with a good diet will significantly increase
your chances of losing weight successfully and
permanently!
47. 2-Weight maintenance plan
The weight reduction is then followed by a 3-
month programme emphasizing weight
maintenance
Exercise is designed to prevent weight regain
once lost by dietary restriction for example
moderate exercise of 30 min. of brisk
walking each day can maintain a weight of
70 kg whereas without such extra activity
the weight
Would plateau out on 77 kg on the same
dietary intake
48. 3-DRUG THERAPY
APPETITE SUPPRESSANTS(anorectic
agents)
The first group :act on the hypothalamus
influencing catecholaminergic pathway
for example amphetamine
Because of their cerebral stimulant action
and potential misuse all are restricted
49. The second group : act on the hypothalamic
serotonergic system namely di-
fenfluramine and dexfenfluramine
They have no cerebral stimulant or addictive
activity
These two drugs were used worldwide for
many years until their withdrawal in 1997
owing to their cardiopulmonary side effects
50. Prescription medications for
losing weight
• Prescription medications should really only be considered as a last
resort. if obesity has reached such a point as to significantly
undermine health, then prescription drugs may become an option.
According to the Mayo Clinic prescription medications should only
be considered if:
• Other strategies to lose weight have failed
• The patient's BMI is over 27 and he also has diabetes, hypertension,
or sleep apnea.
• The patient's BMI is over 30
• There are two approved drugs a physician may consider, Sibutramine
(Meridia in USA/Canada, Reductil in Europe and much of the world)
or Orlistat (Xenical). Bear in mind that as soon as you stop taking
these drugs the overweight problem generally comes back - they have
to be taken indefinitely
51.
52. FAT ABSORPTION INHIBITOR(orlistat)
Orlistat inhibits pancreatic and gastric lipases ,this produces a 30%
reduction in dietary fat absorption which can contribute to a caloric deficit of
about
Adverse side effects are mainly related to the effects of fat malabsorption on
the gut
1-loose oily stools
2-flatus with discharge
3-increased defecation
4-faecal incontinence
Contraindications
1-chronic malabsorption states
2-cholestases
3-hepatic failure
4-Pregnancy
5-breast feeding
6-children
53. • Bulk forming drugs and diuretics should
not be used to enhance fat loss
• Thyroid replacement therapy should only
be used in obese persons when there is
evidence of biochemical hyperthyroidism
and not otherwise
54. 4-VERY-LOW-CALORIE DIETS(VLCD)
• produce weight loss of 1.5-2.5 kg/week
• They are used for short –term rapid weight loss
• Considered only for obese persons with BMI >30
Composition of the diet
The composition of the diet should ensure a minimum
of 50 gm of protein each day for men and 40 gm for
women to minimize muscle degradation
• Energy content should be 400 cal for women and 500
cal for men
• Most use liquid feed although VLCD made of solid
food are used but are less successful
55. Side effects
Side effects may be a problem in the early stages of the diet
,especially orthostatic hypotension ,headache ,diarrhoea and
nausea
Contraindications
1-cardiac disease ,unstable angina, recent myocardial infarction
,significant cardiac arrythmias and cardiac failure
2-cerebrovascular disease ,recent stroke
3-unstable epilepsy
4-major organ system failure
5- protein wasting conditions
6-pregnant women ,during breast feeding and in children
56. Weight loss surgery
(bariatric surgery)
There are two types of bariatric surgeries:
• Restrictive procedures - These make the stomach
smaller. The surgeon may use a gastric band, staples, or
both. After the operation the patient cannot consume
more than about one cup of food during each sitting,
significantly reducing food intake.
• Malabsorptive procedures - Parts of the digestive
system, especially the first part of the small intestine
(duodenum) or the mid-section (jejunum), are
bypassed. Doctors may also reduce the size of the
stomach. This procedure is generally more effective
than restrictive procedures. However, the patient has a
higher risk of experiencing vitamin/mineral deficiencies
because overall absorption is reduced.
57. No patient should undergo bariatric(anti-
obesity) surgery before
Medical investigation and treatment
Psychological assessment has excluded
significant disorders and confirmed that the
patient can cope with the severe dietary
restriction imposed by the surgery
Weight reduction on medical therapy
indicates compliance with the enforced
dietary restrcition after surgery in addition it
makes surgical intervention easier
58. INDICATIONS
The ideal patient is one who has :
No major perioperative risk factors
Stable personality and has no eating
disorders and who has come down to a BMI
of 35 or less with medical management
59. CONTRAINDICATIONS
Major risk category for perioperative cardiac
complications
Significant chronic obstructive lung disease
Non-compliance with medical therapy
Psychological instability
Eating disorders
Hiatus hernia
Gastro-oesophageal reflux disease
60. INTRAGASTRIC BALLOON
• The principle of this intervention is to reduce
gastric volume by inserting a silicon balloon
that has a valve to which is attached a filling
tube
• The deflated balloon is inserted into the
stomach under I.V. sedation and local
pharyngeal anaesthesia
• The position of the balloon is checked by
flexible endoscopy
•
61. • The balloon is then filled with 800 mL
saline and the filling tube is detached from
the valve
• The position of the filled balloon is
checked radiologically
• Intragastric balloons are not intended as a
permanent solution but as a temporary
over a period of 3-4 months to enable
weight loss
62. VERTICAL BANDED GASTROPLASTY (VBG)
Vertical banded gastroplasty open or
laparoscopic is the most commonly performed
procedure
Its advantages include simplicity and ease of
performance
Specific complications include
• Bolus obstruction
• Disruption of the staples partitioning off the
pouch (reduced by double stapling)
• Pouch dilatation
63.
64. RESECTIONAL GASTRIC BYPASS(RGB)
this operation has been advocated recently
and consists of subtotal gastrectomy with
roux-en-Y reconstruction
It produces weight loss by a combination of
reduced intake and malabsorption
Currently , this operation has to be regarded
as a remedial procedure to be undertaken for
failures after less major bar iatric operations
Patients who have undergone ( RGB)require
long-term vit. B12 replacement and an oral
iron therapy
65.
66. Open Roux-en-Y Gastric
Bypass(RYGB)
• RYGB is both a gastric restrictive procedure
and a mildly malabsorptive procedure. A small
gastric pouch restricts food intake, while the
Roux-en-Y configuration provides
malabsorption of calories and nutrients.
• Mason described the optimal parameters for
restriction necessary for adequate weight loss,
including a gastrojejunostomy of 1.2 cm or less
in diameter and a gastric pouch of 15 to 30 mL.
67.
68. Advantages
• The RYGB is more effective than vertical banded gastroplasty in terms of
weight loss. The presence of dumping syndrome following gastric bypass may
encourage patients to avoid sweets.
Disadvantages
• Dumping syndrome occurs in a variable number of patients following gastric
bypass. It is due to rapid emptying of hyperosmolar boluses into the small
bowel. Patients may experience bloating, nausea, diarrhea, and abdominal
pain after ingesting sweets or milk products. Vasomotor symptoms such as
palpitations, diaphoresis, Dumping syndrome may provide a beneficial effect
in promoting weight loss by causing patients to avoid sweets.
• A few postoperative complications are specific to gastric bypass, including
distal gastric distention and internal hernia. Distal gastric distention is often
heralded by hiccups and left shoulder pain. Internal hernia may be difficult to
diagnose. Patients may present with vague periumbilical pain, nausea, and
vomiting. A radiographic upper gastrointestinal study is valuable in
diagnosis. Operative repair is indicated, and involves reduction of the
herniated bowel and suture closure of the mesenteric defect.
69. BILIOPANCREATIC DIVERSION
This intervention is popular on the Europian
continent and results in substantial weight loss
(average 70% at 2 years)
This operation consist of distal two-thirds
gasterectomy with closure of the duodenal stump
The ileum is then transected 250 -350 cm from the
ileo-caecal valve ,the distal end (alimentary
limb=250-350 cm) is closed and brought up for end
–to-side anastomosis with the gastric reminant
The proximal end (biliopancreatic limb) is
anastomosed end –to-side to the alimentary limb
about 50 cm from the ilio-caecal valve
70.
71. Laparoscopic Adjustable Gastric
Banding (LAGB)
• Adjustable gastric banding involves the minimally
invasive (laparoscopic) or open-approach
placement of a silicone band around the proximal
stomach to restrict the amount of solid food that
can be ingested at one time. Furthermore, the
adjustable nature of the band allows the amount of
restriction to be increased or decreased, depending
upon the patient's weight loss. The Food and Drug
Administration approved the laparoscopic
adjustable gastric band for use in the United States
in June 2001.
72.
73. Advantages
Laparoscopic adjustable gastric banding is a relatively simple
procedure that takes less operative time than the more
complex procedures such as laparoscopic RYGB or laparoscopic
biliopancreatic diversion. No staple lines or anastomoses are
required. The adjustable nature of the laparoscopic band allows
the degree of restriction to be optimized for the patient's
weight loss.
Disadvantages
• the need for frequent postoperative visits for band adjustment.
Some patients (5 to 10%) experience band slipping or gastric
prolapse, which usually requires reoperation. Other potential
problems include band erosion, gastroesophageal reflux,
alterations in esophageal motility, and esophageal dilatation.
74. REMEMBER THAT
• The under –excercising and over-eating are the causes
of obesity always walk as much as possible every day
• You can eat what you like and grow thin provided you
make sure that your caloric intake is less than your
caloric expenditure
• Mental work does not require additional calories
• Alcohol may be an important factor in the causation of
obesity ,alcohol is used by the body solely as a source
of energy and thus it frees an equivalent number of
food calories which are then stored as fat
• To weigh yourself regularly this will show how
successful are your efforts to reduce over weight
