Obesity and Your Daily Life

Wen Jie Zhang, MD, PhDProfessor of Pathology

School of Medicine, Health Sciences and EngineeringSusquehanna Township High School

Lecture Series Week 1, August 2014

Clinical Relevance of This Week’s Topic

Screening for Cervical Cancer in China

Teaching and Learning StrategyScientific Research Reports/Articles

Introduction/Background• Identifying a disease to study

– Diagnosis, Treatment, Prevention, etc.

Materials and Methods• Mice/Patients, Reagents/Device/Tests

Results• Measurements obtained and analyzed

Discussion (and Conclusion)• The results’ meaning, significance, and conclusion(s)

References/Further Readings

Learning Objectives

• What is obesity• Consequences of obesity• How to measure obesity• How to classify obesity• Obesity control and prevention

Session 1

Introduction

Obesity – An Individual’s Challenge

• Daily news in public media• Intense scientific reports• Commercial Ads on fat reduction• An Individual’s questions:– Am I overweight or obese?– What to eat/drink and what not to?– Should I be on diet?– How should I exercise to reduce weight? – Should I consult a doctor for advice?

Which one is your favorite?

More, please!

Should I do it ?

The World’s Largest McDonald’s Built on April 23, 1992 Beijing China (~Tiananmen Sq) 29 cash registers 700 seats 40,000 customers/1st Buz day

Buddy, Do I have a piece?

Definition of Obesity

• A medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health risks.

• Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to measure/classify underweight, overweight and obesity in adults.

Body Mass Index (BMI)

• BMI is defined as the weight in kilograms divided by the square of the height in meters (unit=kg/m2).

– Formula: BMI = mass (kg) ÷ height (m)2 = kg/m2

– Example: BMI = 68.2 kg ÷ (1.7m)2 = 68.2÷ 2.89 = 23.6 kg/m2

Table 1: The International Classification of adult underweight, overweight and obesity according to BMI

Classification BMI (kg/m2)Principal cut-off

pointsAdditional cut-off

pointsUnderweight <18.50 <18.50 Severe thinness <16.00 <16.00 Moderate thinness 16.00 - 16.99 16.00 - 16.99 Mild thinness 17.00 - 18.49 17.00 - 18.49

Normal range 18.50 - 24.9918.50 - 22.9923.00 - 24.99

Overweight ≥25.00 ≥25.00

Pre-obese 25.00 - 29.9925.00 - 27.4927.50 - 29.99

     Obese ≥30.00 ≥30.00

Obese class I 30.00 - 34.9930.00 - 32.4932.50 - 34.99

Obese class II 35.00 - 39.9935.00 - 37.4937.50 - 39.99

Obese class III ≥40.00 ≥40.00

Source: Adapted from WHO, 1995, WHO, 2000 and WHO 2004.

“Globesity” – Obesity, A Global Issue

On a worldwide scale• Nutrition improvements and excessive high

energy food• Lifestyle shift (less active)• Global pandemic trends

Source: WHO, Global Database on Body Mass Index

Characteristics of BMI

• Age-independent• Same for both sexes (females may have 1.0

kg/m2 higher than females)• Population differences– May not correspond to the same degree of fatness– BMI-associated health risks may differ• Caucasians vs. Blacks vs. Asians

Obesity Pandemic Around the Globe 1

Source: WHO, Global Database on Body Mass Index

Percent of Adults with BMI 18.5-24.99

Obesity Pandemic Around the Globe 2

Source: WHO, Global Database on Body Mass Index

Percent of Adults with BMI ≥30

Super Obesity

A "super obese" male with a BMI of 47 kg/m2:weight 146 kg (322 lb), height 177 cm (5 ft 10 in)

Super Obesity

Hands-on Laboratory Work

Session 2Materials/Subjects and Methods

Session 3Results/Observations

Results – Observed

• BMI = 18.5-24.99 xx persons, %• BMI = 25-29.99 xx persons, %• BMI ≥ 30 xx persons, %

Session 4

Discussion/Conclusion(s)

Correlation between BMI and Body Fat%

Bod

y Fa

t

BMI

3 Major Risk Factors of Obesity

• Excessive food energy intake• Lack of physical activity• Genetic susceptibility– 58 genetic loci associated with obesity traits

identified – >18 BMI-associated loci shared by European and

East Asian ancestry populations – FTO (Fat Mass and Obesity Associated) gene– Leptin (adipo-cytokine) gene

Consequences of Obesity

• Increased mortality• Increased health risks– Hypertension, coronary heart disease, stroke– Type 2 diabetes– Dyslipidemia – Sleep apnea and respiratory problems– Gallbladder disease– Osteoarthritis – Cancers (10 common cancers including colon, breast,

endometrial) (2014 “Lancet” journal report)

Treatment of Obesity

• Bariatric (fat reduction) surgery– Most effective– Long-term weight loss– Decreased overall mortality

• Medications– Modest weight loss (2.9 kg [6.4 lb]) in 1 to 4 years– Side effects concerns

• Gene therapy?

Prevention of Obesity

• Dietary changeLower food energy diet (long-term or permanent)Limit weight gain more than weight loss

• Physical exercise Long-term or permanentLimit weight gain more than weight loss

Session 5

References/Literature(Further Readings)

References/Further Readings

• The Obesity Society– http://www.obesity.org/

• World Health organization (WHO) Global Database on Body Mass Index- http://apps.who.int/bmi/index.jsp

• The Scientific American (journal)– Popkin BM. Sci Am, 2007 Sep;297(3):88-95

Key Words Learned• Obesity• Body Mass Index (BMI)• Epidemic / Pandemic• Genetic susceptibility• Life expectancy• Bariatric surgery• Dietary change• Physical activity

Your Private Project

• Based on what you have learned, figure out your daily food consumption and make yourself a plan for healthy diet and physical activities.

• Measure your BMI on a fortnightly or monthly basis to monitor your body weight.

• Serve as a “physician” for your family members and monitor their BMI monthly

The End