Learning Objectives

After completion of this module students will be able to:

• Describe the prevalence of obesity by race, ethnicity and geographic location across the United States.
• Explain how BMI is calculated, and describe different cut points for obese and overweight population subgroups
• Describe the costs of being obese or overweight in terms of health care (hypertension, type 3 diabetes, heart disease, cancer) and mortality rates.
• Describe proposed causes and risks for obesity.
• Describe population level intervention strategies currently being explored to combat obesity in the U.S.

Key Concepts - Epidemiology:

• In 2013, obesity was classified as a treatable disease.
• Definition and measurement of obesity—there are pros and cons of relying on Body Mass Index (BMI).
• There has been a sharp increase in obesity in the U.S. since 1960 among children and adults of all ages.
• Prevalence of obesity is higher among some socio-economic, racial, and ethnic groups.
• Population-level intervention strategies are being explored to reduce obesity prevalence but implementation is difficult and change is slow.

Key Concepts - Pathophysiology and Treatment

• Obesity is defined as excess body fat.
• Age, gender, and muscle mass differences make BMI a less accurate measure of fat but the gold standard is air displacement plethysmography (ADP), which is a direct measure of fat, but is very costly.
• Imbalances between energy intake and energy expenditure result in weight loss and gain
• Risk for heart disease, diabetes, and cancer increase when waist size exceeds 35” in women and 40” in men.
• Excess adipose tissue produces harmful hormones.
• Three approaches for treating obesity in adults have been studied: lifestyle modification (diet, exercise), pharmacology, and bariatric surgery.

Video Microlectures

• Video: Epidemiology of Obesity
  Dr. Diana Grigsby-Toussaint, Kinesiology & Community Health, University of Illinois at Urbana-Champaign

• Video: Obesity: Pathophysiology and Treatment
  Dr. Nana Gletsu-Miller, Department of Nutrition Science, Purdue University

Optional Readings

• Sturm R, & An R. (2014). Obesity and economic environments. CA- A Cancer Journal for Clinicians. doi: 10.3322/caac.21237.
• Danaei G., Ding E. L., Mozaffarian D., Taylor B., Rehm J., Murray, C. J. L., & Ezzati, M. (2011). The preventable causes of death in the United States: Comparative risk assessment of dietary, lifestyle, and metabolic risk factors. PLOS Medicine 8, 1-24. doi: 10.1371/annotation/0ef47acd-9dcc-4296-a897-872d182cde57.