Obesity is a state of excess adipose tissue mass. A massive psychosocial, pathophysiological problem that results in a high rate of mortality as well as morbidity. The basic mechanisms of the illness and its management as of 2017 are described in this presentation
2. Origin of the problem
Food supplies used to be intermittent
Storing energy in excess of what is required for immediate use
was and is essential for survival.
Adipose tissue - stores excess energy efficiently as triglycerides
Releases stored energy as free fatty acids for use when needed
This physiologic system, orchestrated through endocrine and
neural pathways, permits humans to survive starvation for as long
as several months.
Now however… nutritional abundance & a sedentary lifestyle, and
influenced importantly by genetic this system increases
adipose energy stores and produces adverse health
consequences.
3. Definition
Def: Obesity is a state of excess adipose tissue mass.
Although often viewed as equivalent to increased body
weight need not be the case
Although not a direct measure of adiposity, the most
widely used method to gauge obesity is the body mass
index (BMI) i.e. kg/cm2
5. Dwayne (The Rock) Johnson
Height: 190 cm
Weight: 113 kg
BMI: 31.3
Is he obese??
6. Introduction
Other approaches to quantify obesity
Anthropometry (skinfold thickness)
Densitometry (underwater weighing)
Computed tomography (CT)
Magnetic resonance imaging (MRI)
Electrical impedance
Other indices
Lean mass index
Fat percentage
7. Introduction
The distribution of
adipose tissue in different
anatomic depots also has
substantial implications
for morbidity
This distinction is made
clinically by the waist-to-
hip ratio (WHR)
>0.9 in women
>1.0 in men
ABNORMAL
8. Prevalence
Estimated that over 12% of the world’s adult
population is obese
Estimations in India reveal that 5-12% are
obese
⅓ of the adult population of the US Obese
9. Physiological regulation of energy balance
Body weight is regulated by both endocrine and neural components
Alterations in stable weight by forced overfeeding or food deprivation
induce physiologic changes that resist these perturbations
15. Medical causes
Cushing’s syndrome
Hypothyroidism
Insulinoma
Craniopharyngioma and other disorders
involving the hypothalamus
Drug induced
22. Work up
Physical exam – Focus on possible complications
Investigations:
Blood sugar, lipid profile, liver function tests
Other tests based on clinical features
TSH, Sleep studies
Dexamethasone suppression test for Cushing’s syndrome*
27. Diet
The primary focus of diet therapy
is to reduce overall calorie
consumption
Very low energy diets (e.g., 400 to 600
kcal/d)
Low-calorie diets, >800 kcal/d
very low fat diets
very low carbohydrate “Atkins” style
diets
Guidelines recommend initiating
treatment with a calorie deficit of 500–
1000 kcal/d compared with the
patient's habitual diet.
28. Diet
The revised Dietary Reference Intakes for
Macronutrients released by the Institute of Medicine
recommends
45–65% of calories from carbohydrates,
20–35% from fat, and 10–35% from protein.
daily fiber intake of 38 g (men) and 25 g (women) for
persons over 50 years of age and
30 g (men) and 21 g (women)for those under age 50.
29. Diet
Low-carbohydrate, high-protein diets appear to be
more effective in lowering BMI;
improving coronary heart disease risk factors, including
an increase in HDL cholesterol and a decrease in
triglyceride levels;
controlling satiety in the short term compared with
low-fat diets
30. Diet
Occasionally, very low calorie diets (VLCDs) are
prescribed as a form of aggressive dietary therapy.
The primary purpose of a VLCD is to promote a rapid
and significant (13–23 kg) short-term weight loss over a
3- to 6-month period.
These propriety formulas typically supply 800 kcal, 50–
80 g protein, and 100% of the recommended daily
intake for vitamins and minerals.
31. Exercise
Increased energy expenditure is the
most obvious mechanism for an
effect of exercise
Exercise appears to be a valuable
means to sustain diet therapy
Valuable in the obese individual for its
effects on cardiovascular tone and
blood pressure
32. Pharmacotherapy
Recommended if BMI >/= 27 with
comorbidities or BMI >/= 30
Facts:
Drugs alone cause modest weight loss
Diet with drugs improves efficacy
Effects maintained for duration of treatment
only
Long term safety data not available
33. Pharmacotherapy
Medications for obesity have traditionally
fallen into two major categories:
1. Appetite suppressants (anorexiants)
2. Gastrointestinal fat blockers
34. Pharmacotherapy
Centrally Acting Anorexiant Medication
Anorexiants increases satiety and decreases hunger,
these agents help patients reduce caloric intake without
a sense of deprivation.
Targets the ventromedial and lateral hypothalamus
Eg PHEN/TPM (Phenteramine and Topiramate) 9.3%
and 8.6% weight lost in 2 large trials
35. Pharmacotherapy
Centrally Acting Anorexiant Medication
Lorcaserin is a selective 5-HT2C receptor agonist
thought to decrease food intake through the pro-
opiomelanocortin system of neurons.
36. Pharmacotherapy
Peripherally Acting Medications
(Gastrointestinal fat blockers)
Orlistat is a synthetic hydrogenated derivative of a
naturally occurring lipase inhibitor, lipostatin
Potent, slowly reversible inhibitor of pancreatic, gastric,
and carboxylester lipases and phospholipase A2
required for the hydrolysis of dietary fat into fatty acids.
Acts in the lumen of the stomach and small intestine
Blocks the digestion and absorption of ~30% of dietary
fat
Weight loss of ~9–10%
38. Surgery
Indications
BMI > 35 with an associated comorbidity or a BMI > 40
(irrespective)
Repeated failures of other therapeutic approaches
Capability of tolerating surgery
39. Surgery
Weight loss surgeries have traditionally been classified into 3
categories on the basis of anatomic changes:
Restrictive
Restrictive-malabsorptive
Malabsorptive
Clinical benefits of bariatric surgery in achieving weight loss and
alleviating metabolic comorbidities have been attributed largely to
changes in the physiologic responses of gut hormones and in
adipose tissue metabolism.
40. Surgery
Restrictive surgeries limit the
amount of food the stomach can
hold and slow the rate of gastric
emptying.
Malabsorptive surgeries reduce the
amount of absorption
A. Laparoscopic gastric band (LAGB)
B. The Roux-en-Y gastric bypass.
C. Biliopancreatic diversion with duodenal
switch.
D. Biliopancreatic diversion.vertical-banded
gastroplasty
E. Biliopancreatic diversion
41. Surgery
These procedures generally produce a 30–35% average total body weight
loss that is maintained in nearly 60% of patients at 5 years.
Significant improvement in multiple obesity-related comorbid conditions,
including type 2 diabetes, hypertension, dyslipidemia, obstructive sleep
apnea, quality of life and long-term cardiovascular events.
The most common surgical complications include stomal stenosis or
marginal ulcers
The restrictive-malabsorptive procedures carry an increased risk for
micronutrient deficiencies of vitamin B12, iron, folate, calcium, and
vitamin D.
Patients with restrictive-malabsorptive procedures require lifelong
supplementation with these micronutrients.