What Is Obesity?

Obesity is the medical term for a condition of having an excess of body fat and is characterized by having a body mass index (BMI) that is greater than 30. It can have a variety of causes, including genetic, environmental, and lifestyle factors. Obesity is a common health condition in the U.S. The Centers for Disease Control and Prevention (CDC) has estimated that roughly 40 percent of all adult Americans are obese, that is, substantially overweight. Obesity is associated with a number of health risks, including cancer, diabetes, stroke, and heart disease, and is also linked to increases in early mortality. 

Fortunately, obesity is easily diagnosed and often responds to a range of treatment options, including dietary changes, increased physical activity, weight-loss medications, endoscopic procedures, and, when warranted, bariatric or weight-loss surgery. For more information, see your Baptist Health medical provider or a member of our bariatric team.


Being obese means having too much body fat, but how much is too much? Medical researchers have developed an objective measure of body fat called the body mass index or BMI. BMI relates a person’s weight to his or her height, as a means of estimating excess fat. To determine your BMI, pide your weight in pounds by your height in inches squared. Then multiply the total by 703, which converts the formula from a metric to a U.S. customary basis. The following weight classifications for adults are associated with specific BMI ranges:



Below 18.5 Underweight
18.5-24.9 Normal Weight
25.0-29.9 Overweight
30.0 & higher Obese

For medical purposes, an adult with a BMI of 30 or higher is considered obese. This means that he or she has an elevated risk level for developing a number of health conditions, including heart disease, stroke, type-2 diabetes, sleep apnea, osteoarthritis, cancer, heartburn and related digestive problems, female infertility, and male sexual dysfunction. 

BMI is a reasonable rule-of-thumb measure for estimating body fat but it has shortcomings. For example, muscle is denser than fat, so it’s possible to gain weight through exercise, even while developing a slimmer physique. This means that some athletes have a surprisingly high BMI while having little excess body fat. 

What Causes Obesity? 

Obesity can have a variety of causes, with heredity, environment, personal behavior, and other factors all contributing. Potential causes include:

  • Genes: Genes play an important role in governing an individual's metabolism, including where and how much fat is stored in and by the body. Because of this, obesity often runs in families. 
  • Lifestyle: Personal choice is pivotal in matters of weight gain. The amount and types of food eaten, and the extent of physical activity undertaken, has a direct bearing on whether someone is likely to become obese. 
  • Age: Obesity can develop at any age but is more likely in older persons. This is the natural result of a slowing metabolism and decreased physical activity. 
  • Pregnancy: Pregnant women typically gain weight, which is often difficult to lose even after giving birth. 
  • Stress: A common strategy for coping with stress is eating more. This can be seen in individuals who gain weight while trying to quit tobacco use. 
  • Sleep deficit: A lack of quality sleep can lead to fluctuations in the body’s hormone levels. These changes can trigger increases in appetite and food consumption. 
  • Life environment: Environmental factors are relevant to weight gain. Persons who live in urban “food deserts” may have to rely on high-caloric fast-food restaurants for much of their daily diet. 
  • Certain medical conditions: A number of medical conditions are linked to weight gain, including hypothyroidism, osteoarthritis, Cushing syndrome, and polycystic ovary syndrome. Certain medications, including antidepressants, steroids, beta-blockers, and diabetes drugs, can also lead to increases in body mass. 

How Is Obesity Diagnosed?

Your physician will take the following steps to diagnose obesity:

  • Document your symptoms and medical history, including whether any family members have dealt with issues of excessive weight gain.
  • Conduct a physical exam, including vital signs, height, weight, and waist measurements, and other pertinent analytical factors. 
  • Calculate your BMI. Remember that a BMI of 30 or more is the medical definition of obesity. 
  • Administer blood tests, including cholesterol, liver function, thyroid, and fasting glucose levels. 
  • Look for evidence of other medical conditions that may be affecting weight, including diabetes and hypertension.

To more accurately assess the amount and distribution of your body fat, your physician may order CT scans, ultrasounds, or magnetic resonance imaging (MRI) exams. In certain instances, he or she may also arrange a heart test, such as an electrocardiogram (EKG). 

How Is Obesity Treated?

The primary objective in treating obesity is to reduce medical risk through weight loss. There are several options for achieving this end:

Better Diet

Weight gain occurs when individuals consume more calories than they burn over a given period of time. One means of addressing obesity is an improved diet. Eating healthier meals, with fewer calories but better overall nutritional value, is central to treating obesity. 

Increased Physical Activity

Another positive step one can take is to increase physical activity. This will allow your body to burn more calories, rather than store them as new fat deposits. Taking up an outdoor pastime or developing an exercise program are effective alternatives to a too-sedentary lifestyle.  

Weight-loss Medications

If changes in personal behavior aren’t generating sufficient weight loss, your physician may recommend a weight-loss medication. Several such drugs are currently in use, including bupropion, liraglutide, naltrexone, orlistat, phentermine, and topiramate. 

Endoscopic Procedures

Endoscopic procedures are another option for reversing obesity. An endoscope is a thin, flexible tube that can be inserted into the body without an incision. Surgeons use endoscopes to reduce appetite either by closing off part of the stomach with stitches or by placing a small, water-filled balloon inside it. The resultant weight loss often equals between five and 20 percent of total body mass. 

Bariatric Surgery

Bariatric surgery is another, more intensive form of weight-loss surgery. It covers a variety of procedures that decrease stomach size, reduce food absorption, or both. Persons undergoing bariatric surgery often achieve major weight loss, due to diminished appetite and greater satiety (feeling of fullness) when eating. These procedures tend to be reserved for the most serious cases of obesity, that are not otherwise responding to treatment and changes in personal behavior.

Learn More About Obesity from Baptist Health

Obesity is a major contributor to many common medical problems. If you are interested in healthy ways to counteract excess weight gain, see your Baptist Health provider. If you’d like to learn more about bariatric surgery, make plans to attend a Baptist Health weight-loss seminar.

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