Assessment of Obesity biochemistry

1. Assessment of Obesity
MARYAM JAMILAH BINTI ABDUL HAMID
082013100002
IMS BANGALORE

2. Learning Outcome
• Definition of obesity
• Assessment of obesity

3. Obesity
A medical condition in which excess body
fat has accumulated to the extent that it
may have a negative effect on health,
leading to reduced life expectancy
and/or increased health problems.

5. Assessment of Obesity
• Body mass index (BMI)
• Anatomic differences in fat deposition
• Biochemical differences in regional fat
depots
• Size and number of fat cells

6. a) Obesity Index/Body Mass
Index (BMI)

7. WH
a) Obesity Index/Body Mass Index (BMI)
A measure of relative weight based on an individual's mass and
height 2
W = Weight (kg)
H = Height (m)
or BMI= (weight in lb)/(height in inches)2 × 703
Nearly 2/3 of American
adults are overweight and
more than 1/3 are obese

8. 1 stone = 14 pounds = 6.35 kg
1 kg = 2.2 pounds

10. • BMI is accurate most of the
time
• However may overestimate
or underestimate body fat.
• Does not distinguish
between body fat
and muscle mass, which
weighs more than fat.
• Many NFL players have
been labelled "obese"
because of their high BMI,
when they actually have a
low percentage of body fat

11. b) Anatomic differences in fat
deposition

12. b) Anatomic differences in fat deposition
• It has a major influence on associated
health risks
• Excess fat located in the central
abdominal area of the body is called
android, “apple-shaped,” or upper body
obesity
(greater risk for hypertension, insulin
resistance, diabetes, dyslipidemia, and
coronary heart disease)
• Waist to hip ratio
Women > 0.8
Men > 1.0

13. • In contrast, excess fat in the lower extremities around
the hips or gluteal region is call gynoid, “pear-shaped,”
or lower body obesity
• Waist to hip ratio
Women < 0.8
Men < 1.0
• Commonly found in females (lower risk metabolic
disease)
• Some experts feel that the waist-to-hip ratio is better
than BMI as predictor of myocardial infarction

14. 80-90% of fat stored in
subcutaneous depots
(under the skin,abdominal
& lower body region)
10-20% of fat stored in
visceral depots (omental&
mesenteric)

15. c) Biochemical differences in regional
fat depots

16. • Men tend to accumulate the readily mobilizable
abdominal fat, they generally lose weight more readily
than women do
• Substances released from abdominal fat are absorbed via
the portal vein and, thus, have direct access to the liver
• Fatty acids taken up by the liver may lead to insulin
resistance and increased synthesis of triacylglycerols,
which are released as very-low-density lipoprotein (VLDL)
• By contrast, free fatty acids from gluteal fat enter the
general circulation, and have no preferential action on
hepatic metabolism

17. c) Biochemical differences in regional fat
i. Abdominal fat cells
• much larger
• higher rate of fat
turnover
• adipocytes are
hormonally more
responsive than fat
cells in the legs and
buttocks
ii. Lower body fat cells
• much smaller
• lower rate of fat
turnover
• adipocytes are
hormonally less
responsive than fat
cells in abdominal
depots

18. d) Number of fat cells

19. Hypertrophic and
hyperplastic
changes thought to
occur in severe
obesity

20. • When triacylglycerols are deposited in
adipocytes, the cells initially show a modest
increase in size
• However, the ability of a fat cell to expand is
limited, and when its maximal size is reached,
it divides

21. • Most obesity is, therefore, thought to involve
an increase in both the number and size of
adipocytes
• Fat cells, once gained, are NEVER LOST
• Thus, when an obese individual loses weight,
the size of the fat cells is reduced, but the
number of fat cells is not affected

22. • An obese individual, with increased numbers
of adipocytes, will have to reduce the size of
those fat cells in order to normalize fat stores
• These individuals will be in the doubly
abnormal state of having too many, too small
fat cells

23. • Formerly obese patients have a particularly
difficult time maintaining their reduced body
weight
• The observation that fat cells are never lost
emphasizes the importance of preventing
obesity in the first place

24. Conclusion
• Assessments of obesity are described

25. References
• Lippincott’s Illustrated Reviews: Biochemistry,
4th edition
• DM Vasudevan, Biochemistry Textbook for
Medical Students
• http://health.howstuffworks.com/wellness/di
et-fitness/weight-loss/bmi3.htm
• http://en.wikipedia.org/wiki/Obesity