Medical-Fitness Technician
Certification Course
Part B: Exercise & Patho-Physiology (LM:11-24)
Learning Module 13:
Exercise & Obesity
Study the Learning Module with the Video and take the Quiz.
Learning Objectives 
  • Know the definition and prevalence of obesity.
  • Know some of the causes and complications of obesity.
  • Know the basic medical approach for the treatment of obesity.
  • Understand the relationship between exercise and obesity.
Definition: Obesity is defined by the Obesity Medicine Association (OMA) as a “chronic, relapsing, multi-factorial, neurobehavioral disease, wherein an increase in body fat promotes adipose tissue dysfunction and abnormal fat mass physical forces, resulting in adverse metabolic, biomechanical, and psychosocial health consequences.”
  • Obesity was first recognized as a disease in 1948 by the World Health Organization (WHO).
  • The American Medical Association (AMA) did not recognize obesity as a disease until 65 years later in 2013.
  • Obesity is caused by a complex interplay among genetic, environment, behavioral, cultural, and many other factors.
  • An easy way to classify obesity is on the basis of BMI.
  • A BMI of 21-25 is considered a healthy weight for the person's height.
  • ​Overweight (pre-obesity) has a BMI of 26-29
  • Class 1 Obesity has a BMI of 30-34
  • Class 2 Obesity has a BMI of 35-39
  • Class 3 Obesity has a BMI of 40+ (morbid obesity)
  • Although using BMI is a commonly accepted classification of obesity, it has its limitations as it does not consider percent body fat (%BF) or the abdominal distribution of unhealthy weight, which is a higher risk type of obesity.
Causes of Obesity: Obesity is a medical disease that occurs when a person’s body accumulates and stores excessive amounts of body fat. There are many factors that contribute to obesity, including:
  • Genetics contribute from 40% to 70% of obesity. There are thousands of different genes associated with obesity, and some genetic mutations are known to directly cause obesity. However, possessing genes that predispose you to obesity does not mean developing obesity is inevitable or not reversible.
  • Nutrition: Growing evidence shows that not all calories are created equal. Certain foods, such as refined carbohydrates and unhealthy saturated fats, contribute in greater proportion to obesity.
  • Hormones: Abnormalities in several biological pathways are involved in obesity. Insulin resistance, which causes the body not to process sugar properly, has been heavily implicated in obesity.
  • Medication: Many prescription medications are associated with weight gain, including most antidepressants, steroids, contraceptives, and medications for the treatment of diabetes, hypertension, migraines, seizures, bipolar disorder, allergies, insomnia, and more.
  • Environment: Family, occupation, commuting, entertainment, culture in which physical activity has been severely limited all have a significant (but reversible) impact on developing and maintaining obesity.
  • Sleep: Disrupted sleep and sleeping for less than 7 hours or more than 9 hours contributes to obesity.

Complications: Current studies show that obesity decreases the lifespan by 8 years (on average), which is comparable to the health effects of smoking. There are 236 other Diseases impacted by obesity, 13 of which are Cancers.​
  • Both biological and lifestyle factors associated with obesity can contribute to the higher risk of cancer.
  • Fat cells produce chemicals harmful to the body (cytokines), causing inflammation that can damage healthy cells over time.
  • Fat cells can also increase hormone levels that can trigger genes in people with higher risks for certain cancers.
  • Other related lifestyle factors (less exercise) also play a part in the connection between obesity and cancer.
  • Proper nutrition and physical activity are key components in lowering the risk for both obesity and cancer.
  • The 13 types of Cancer that have been shown to have the strongest association with obesity are (alphabetically): Breast (in post-menopausal women), Colon & Rectum, Esophageal, Gallbladder, Kidney, Liver, Meningioma (cancer of the brain and spinal cord coverings), Multiple Myeloma (a type of cancer of certain blood cells), Ovaries, Pancreas, Thyroid, Stomach, and Uterus.
  • Type 2 Diabetes - More than 85% of patients with type 2 diabetes also suffer from overweight or obesity. With significant weight loss from proper nutrition and regular exercise, Type 2 Diabetes is reversible and often cured.
  • Hypertension (High Blood Pressure) - Obesity and fat distribution are both determinants of hypertension risk. For those suffering from hypertension, weight loss (of 10% body weight or more) can lead to a significant drop in blood pressure, lessening the need for medications, as well as lowering the risk for hypertension-related diseases.
  • Sleep Apnea - 1 in 5 Americans are estimated to be affected by sleep apnea. People with sleep apnea experience momentary cessations of breathing while they sleep, which may contribute to dementia.
  • Depression is common in patients with overweight and obesity. Obesity increases the risk of developing depression up to 45%, Symptoms of depression (fatigue, low-energy, increased or decreased sleep, and over-eating) is often the cause of obesity.
  • Osteoarthritis (inflammation and pain in the weight-nearing joints - hips and knees) is a common complication of and a contributing factor to obesity.

Prevalence: Obesity is the most common chronic disease in the United States.
  • About 2/3's of adults and 1/3 of teens and children are affected by overweight and obesity.
  • Within 15 years, it is estimated that 50% of the U.S. adult population will suffer from obesity.
  • The estimated cost of obesity to the United States is $1.42 trillion.
  • Obesity accounts for 15% of healthcare expenditures.
  • Obesity directly causes 320,000 deaths per year.
  • Losing just 5% of body weight can save an individual with a BMI > 40 over $2,000 per year.
  • Higher education levels are associated with a lower risk of obesity.

Treatment of Obesity: Medical professionals try to use a comprehensive, evidence-based approach to manage and treat obesity.
  • This approach is comprised of four pillars: nutrition, exercise, eating behavior/patterns, and medication/surgery.
  • Nutritional treatment includes implementing prepackaged meals, decreasing portion sizes, and decreasing intake of certain foods or types of foods.
  • Physical activity treatment may include starting a walking program or progressing to a regular exercise pattern based on the patient’s current levels of activity.
  • Behavioral goals can include modifications like eating slowly; eating smaller portions; paying attention to when, how, and what you eat; and identifying reasons or triggers for eating when not hungry.
  • Medication is the last pillar; there are quite a few medications available that are approved for obesity, but must be administered under the supervision of an obesity medicine specialist. All medications have adverse side-effects.​
Relationship between Exercise & Obesity
Conclusion: Regular exercise helps prevent obesity, helps reverse obesity, and helps protect against the health effects of obesity.