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OBESITY

Nutrition department

Medical school

University of Sumatera Utara

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Globesity: a worldwide problem

0

5

10

15

20

25

Global Least developed Developing Transition Developed

BMI < 17

BMI > 30

In 1995 WHO

estimated there were

200 million obese

people

In 2000 more than

300 million people

were estimated to be

obese

132 million indeveloped countries

170 million in other

countries

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What is Obesity?

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Obesity: Definition

Excess body fat

Fat cells function to store and release

energy

Normal body fat is 10 to 20 kg

Obese body fat is 40 to100 kg

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Levels of Body Fatness

Men Women

Essential fat 5% 10%

Borderline 5-9% 10-16%

High performance 5-15% 10-23%

Good fitness health 10-20% 17-28%

Marginal fitness 21-25% 29-35%

Overfatness > 25% > 35%

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Etiology

1. Genetics factor

- contribute to ones predisposition to or

protection from obesity- include determinations of RMR, where fat is

stored, physiologic response to overfeeding,

eating behavior

- Ob gene produce leptin

- -3adrenoreceptor gene regulate

RMR & fat oxidation

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2. Neuroendocrine syndrome (

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3. Environmental factor primary causes

Dietary excess

- active- passive

Physical inactivity

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4. Epidemiological studies

Age

Gender > Ethnicity

Educational level & income

Marital status ( after marriage)

Parity Smoking

Alcohol consumption

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Decreases with Education

0

5

10

15

20

25

30

1991 2000

< HS

HS

Some College

College +

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Body CompositionAssessment

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Body Composition Assessment

Techniques

Underwater weighing

Technological assessments

Skinfold technique

Anthropometric measurements

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Underwater Weighing Technique

The

"Gold

Standard"

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Underwater WeighingMeasurement issues

Based on body density calculations

Density of lean tissue = 1.1 g/cc

Density of fat tissue = .9 g/cc

General conclusions

Gold standard measure (1-2% error)

Impractical for most applications

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Technological Assessments

of Body Composition

Bioelectric impedance

Infra-red spectroscopy

Ultrasound

Imaging techniques (DEXA, MRI)

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Bioelectric Impedence(Measurement Issues)

Based on resistance to current flow Lean tissue has more water - less resistance

Fat tissue has less water - more resistance

General conclusions Overestimates lean / underestimates obese

Practical, but expensive measure for generalpopulation

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Infrared Spectroscopy(Measurement Issues)

Based on differential absorbance rates Lean tissue has a different energy absorption and

reflectance pattern than fat tissue

Sources of error Validity of absorbance readings is questionable!

General findings NOT a valid measure!

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Ultrasound(Measurement Issues)

Based on reflection of sound Fat content increases the time is required for

sound to reflect off of bone and muscle. General conclusions Highly accurate measure of body fat - especially for

obese

Expensive and not practical for most applications

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Imaging Techniques(Measurement Issues)

Based on imaging of body tissues Based on cross sectional area measures

calculated at different levels of the body

General conclusions Very precise measure of body composition

Expensive and not practical measure for mostuses

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Anthropometric Measurements

Body Mass Index (BMI)

Waist to Hip Ratio (WHR) Circumference measures

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Body Mass Index (kg/m2)

Dose - Response Risk Relationship

Underweight < 18.5

Normal 18.5 - 25Overweight 25 - 30

Obese > 30

Class I 30 - 34.9 Class II 35 - 39.9

Class III >40

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Body Mass Index (kg/m2) in adult Asians

Dose - Response Risk Relationship

Underweight < 18.5

Normal 18.5 22.9Overweight 23

- At risk 23 24.9

- Obese I 25 29.9

- Obese II 30

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Body mass index and total mortality in

the Nurses Health Study

0

0.5

1

1.5

2

2.5

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Regional Fat Deposition

Abdominal body fat poses greater health risks

than fat stored in other areas

Males store more fat

centrally and have

increased health

risks associatedwith body fatness

Higher health riskLower health risk

Male (apple) Female (pear)

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Regional Fat Deposition

Visceral Fat

Visceral body fat poses greater health risks because this

fat is more labile and has greater access to the

circulation.

The accumulation of visceral body fat is typical of the

android (male) fat pattern

males: visceral accounts for 10-35% of total fat

females: visceral accounts for 8-13%of total fat

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WOMENMENHigh Risk

Moderate Risk

Low Risk

> 1.0 > .85

.90 -1.0 .80-.85

HEALTH RISK

< .90 < .80

Waist to Hip Ratio (WHR)

Waist to Hip Ratio is an effective way to

examine regional fat distribution.

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Tipe buah Pear(Obesitas Ginecoid)

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Tipe buah Apel(Obesitas Android)

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