Obesity is defined as "a condition that is characterized by excessive accumulation and storage of fat in the body and that in an adult is typically indicated by a body mass index of 30 or greater" by the Merriam-Webster Medical Dictionary online (accessed Dec. 15, 2009).

Body mass index (BMI) is calculated by taking a person's weight divided by the square of a his or her height (kg/m²). The "normal" BMI range is between 18.5 and 24.9. A BMI between 25 and 29.9 is categorized as overweight, and a BMI of 30 or above is classified as obesity. For example, someone 5'5" tall and 180 lbs or someone 6'0" tall and 221 lbs is considered to have a BMI in the obese range. The BMI correlates with, but does not directly measure, excess body fat. Some people such as athletes may have higher than "normal" BMIs but do not have excess body fat. [1]

The Centers for Disease Control and Prevention (CDC) reported an "epidemic" of 72 million obese people (88 KB) in the United States in 2006 with 34.3% of adults considered obese (vs. 13.4% in 1962) and 32.7% considered overweight (vs. 31.5% in 1962) (111 KB) .

In 2005 obesity accounted for an estimated 216,000 deaths (1 in 10 deaths) among US adults. It was the third-leading risk factor in US adult deaths, after tobacco smoking (467,000 deaths) and high blood pressure (395,000 deaths). [2] Obesity and obesity-related health conditions cost an estimated 10% of annual medical spending in the US, totaling $147 billion in 2008 (121 KB) .

According to a National Consumers League survey (705 KB) conducted by Harris Interactive from Mar. 6-12, 2007, 78% of American respondents agreed with the statement "obesity is a serious chronic disease" and 50% of respondents attributed the condition to "lack of will power." However, a different survey conducted by the Gallup Poll from July 8-14, 2004 (117 KB) showed that 21% of Americans believe "obesity is a disease," while 75% viewed obesity as a "problem of bad eating and bad lifestyle habits."

As of Dec. 15, 2009, the World Health Organization (WHO), FDA, Internal Revenue Service (IRS), and the National Institutes of Health (NIH) have all stated that obesity is a disease. The CDC and the Department of Health and Human Services (HHS) have not taken a position on whether or not obesity is a disease. The US House of Representatives in its Oct. 29, 2009 health care bill H.R. 3962 (3 MB) included obesity as a "behavioral risk factor" and not as a disease.

The debate over whether or not obesity is a disease grows as obesity is increasingly regarded as an epidemic. Proponents stress that obesity is a disease because it is a result of genetics and biological factors, while opponents argue that obesity is not a disease because it is a personal lifestyle choice.

1. Obesity, like other diseases, impairs the normal functioning of a body. People who are obese have excess adipose (or fat) tissue that causes the overproduction of certain molecules and mediators in the body, which lead to abnormal regulation of food intake and energy expenditure. [3]
   
   
2. Obesity decreases a person's life expectancy or can cause death, like other diseases. Obesity in adults can lead to three years loss of life. Extreme obesity can shorten a person's life span by 10 years--comparable to the decrease in years of life from smoking. [4]
   
   
3. Some studies have shown that the hereditability of obesity is about the same as that of height. Therefore obesity is not the result of people lacking willpower to exercise or eat less, but is genetically predetermined. [5][6]
   
   
4. Government entities including the Food and Drug Administration (FDA), National Institutes of Health (NIH), and Internal Revenue Service (IRS) have affirmed that obesity is a disease.
   
   
5. Diseases have characteristic signs, according to general and medical dictionaries. [3][7] Obesity has a characteristic sign--excess fat--which is measured by BMI or increased waist circumference measures.
   
   
6. Obesity is a risk factor for diabetes, hypertension, some cancers, and other diseases. Other risk factors are also defined as diseases, such as hypertension which is defined as a disease because it is a risk factor heart failure and stroke. [8]
   
   
7. Obesity is not just a recent phenomenon resulting from the modern environment. Physicians from as early as the 17th century have referenced obesity as a disease. [9]

1. Obesity does not necessarily impair the normal functioning of a body as other diseases do. Many people with a BMI in the obesity range are not physically impaired and live normal lives.
   
   
2. Unlike other diseases that lead to shortened life expectancy or death, some obese people live long lives and do not develop diseases commonly associated with obesity, such as diabetes.
   
   
3. Obesity is a matter of personal responsibility. People become obese because they make bad dietary decisions and do not exercise enough or at all.
   
   
4. Obesity is the result of sedentary lifestyles and not illness. For example, compared to 40 years ago, people today spend more time commuting, sitting in front of a computer, watching television, playing video games, and generally exercising less. [10]
   
   
5. Obesity does not have characteristic signs or symptoms like diseases typically have. The only characteristic sign of obesity is excess fat, which is the definition of obesity itself. There are also no symptoms for obesity. [7]
   
   
6. Obesity is a preventable risk factor for other diseases, like smoking is a preventable risk factor for lung cancer or like drinking is a preventable risk factor for alcoholism.
   
   
7. Obesity can, in some cases, have positive health benefits such as increasing bone mass and reducing the risk of osteoporosis. [11]

1. 67% of the adult US population (111 KB) was either overweight or obese between 2005-2006.
   
   
2. Mississippi, with an obesity rate of 32.8% in 2008, had the highest prevalence of obesity out of all 50 US states. Colorado had America's lowest rate at 18.5%. [12]
   
   
3. US males rank 5th out of 74 countries (61 KB) in obesity rates, and US females rank 11th out of 114 countries (63 KB) , according to the World Health Organization's data from 2000-2007.
   
   
4. Since 2002, Americans who are medically diagnosed as obese have been allowed to claim federal tax deductions for doctor prescribed treatments, "special food," and weight loss programs (62 KB) .

The debate over whether or not obesity is a disease grows as obesity rates and the cost of treating obesity-related conditions increase in the United States. Proponents stress that obesity is a disease because it is a result of genetics and biological factors, citing scientific studies that have shown a link between obesity and heredity. [5][6][13] Certain known illnesses can also cause weight gain or obesity, including hypothyroidism, Cushing's syndrome, and polycystic ovary syndrome.[10] Opponents argue that obesity is not a disease because it is the result of a person's environment (i.e. residential location, social circle, economic status, etc.), lifestyle, and eating habits, citing other studies that show obesity is a result of environment and social networks. [14][15][16]

The Centers for Disease Control and Prevention (CDC) reported an "epidemic" of 72 million obese people (88 KB) in the United States in 2006 with 34.3% of adults considered obese (vs. 13.4% in 1962) and 32.7% considered overweight (vs. 31.5% in 1962) (111 KB) . 67% of the adult US population was either overweight or obese (111 KB) .

In 2008 Mississippi had the highest rate of obesity out of all the US states at 32.8%. Colorado had the lowest rate at 18.5%. [12] Some experts claim that 25% of vegetables consumed in the United States are in the form of french fries. [17]

US males rank 5th out of 74 countries (61 KB) in obesity rates and US females rank 11th out of 114 countries (63 KB) , according to the World Health Organization's data from 2000-2007.

A study from the Centers for Disease Control and Prevention (CDC) and Research Triangle Institute (RTI International) released in July 2009 estimated that obesity and obesity-related health conditions cost almost ten percent of annual medical spending in the US, totaling $147 billion in 2008 (121 KB) . If classified as a disease, obesity potentially qualifies for coverage by federal and state health care programs, thus diverting public funds to what some view as an individual problem.

In determining whether or not obesity is a disease, researchers have used definitions of "disease" in general and medical dictionaries due to the lack of a widely accepted definition of what constitutes a disease. [3][7][9]

The Federal Drug and Food Administration (FDA), in implementing the Nutrition Labeling and Education Act of 1990, provides a broad definition for "disease or health-related condition" (60 KB) but does not define a disease by itself.

Despite the lack of a universally accepted definition of a disease, several government and international entites have stated obesity is a disease. The FDA in its Jan. 6, 1999 "Regulations on Statements Made for Dietary Supplements Concerning the Effect of the Product on the Structure or Function of the Body; Final Rule," wrote that the FDA "agrees... that obesity is a disease."

The Internal Revenue Service (IRS) announced a policy in 2002 (62 KB) stating that "obesity is medically accepted to be a disease in its own right." This policy allows Americans to claim tax deductions for doctor prescribed treatments, "special food," and weight loss programs for those who are medically diagnosed as obese.

The National Institutes of Health's National Heart, Lung, and Blood Institute wrote, "Obesity is a complex multifactorial chronic disease," in its Sep. 1998 publication "Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults" (1.2 MB) .

The World Health Organization (WHO) called obesity a "chronic disease" in its 2000 report "Obesity: Preventing and Managing the Global Epidemic" (586 KB) .

The American College of Gastroenterology, in its 2008 briefing paper on obesity for gastrointestinal specialists, "Obesity: A Growing & Dangerous Public Health Challenge" (4 MB) , stated that obesity is a "chronic, debilitating and potentially fatal disease."

Other entities have taken a less clear stance on whether or not obesity is a disease. A change in Medicare coverage policy (56 KB) on Oct. 1, 2004 removed the language "obesity itself cannot be considered an illness" from its "National Coverage Determinations Manual (NCDM)," allowing obesity-related medical treatments to be covered under Medicare. The Centers for Medicare and Medicaid Services (CMS) has not classified obesity as a disease.

Similarly, the American Academy of Family Physicians (AAFP), American Academy of Pediatrics (AAP), American College of Physicians (ACP), and American Nurses Association (ANA) do not have policy statements stating whether or not obesity is a disease, as of Dec, 17, 2009. The American Medical Association (AMA) has stated support for treating obesity as a disease for various reasons, although it has not stated obesity is a disease. [3]

In the health care bill H.R. 3962 (3 MB) approved by the House of Representatives on Oct. 29, 2009, "being overweight or obese" is not classified as a disease but as a "behavioral risk factor" along with alcohol and drug use, tobacco, poor nutrition, physical inactivity, and risky sex.

With a lack of clear consensus among government entities and medical associations on whether or not obesity is a disease, advocate groups continue to lobby for and against classifying obesity as a disease. Proponents stress that declaring obesity is a disease would remove the social stigma associated with obesity, afford it the same legal protections as other illnesses, and force medical professionals, insurers, and employers to treat it with the same degree of concern given other diseases.

Opponents argue that classifying obesity as a disease would scare overweight or obese people who are healthy into seeking unnecessary medical treatments, divert public funds to treat a preventable condition, and be discriminatory towards people who choose a different body type. They say that categorizing obesity as a disease would not address the underlying problems causing it, such as poverty, the prevalence of unhealthy processed foods, lack of public policies encouraging exercise, and other environmental factors.

[None received as of Jan. 6, 2009]

1. "Whether weight is lost or gained is pure chemistry: calories( food energy) in= calories (physical & chemical work) expended: no weight gain. There were no over-weight people in Nazi Germany's extermination/labour camps. Excess food is the problem. Obesity reflects a food addiction, but it is not a disease."
   Anonymous, Jan. 1, 2010
   
   
2. "There are metabolically normal obese individuals who do not suffer from any of the adverse effects of having large amounts of body fat because they are genetically predisposed to being large people, and they maintain healthy lifestyles, i.e. eat a nutrient dense diet and are physically active. On the other hand, there are obese persons who have large bodies as the result of unhealthy lifestyles, i.e. poor dietary intake and sedentary. These people will suffer the ill effects of having an excess of body fat. The mistake we have made is to categorize all large people as 'obese' and to ascribe the same health risks to both groups."
   Joanne P. Ikeda, MA, RD, Nutritionist Emeritus, University of California, Berkeley and Co-founder of the Center for Weight and Health at UC Berkeley, Dec. 31, 2009
   
   
3. "Obesity is not a disease. Obesity is a body characteristic, not a character flaw. People come in diverse heights, weights, colors, etc. Size diversity is the nature of human beings. It is a prejudice and stereotype that all fat people are lazy and glutinous. The medical community and media use large body size as short hand for overeating and sedentary. It is not. When people eat healthy and exercise regularly, some will be small, medium, large, and very large.
   
   ...When people have poor dietary habits and sedentary lifestyles, independent of size, they will have more illness and shorter lives. When people of any size improve their actions of self-care, they will improve their health."
   Kelly Bliss, psychotherapist and fitness professional, Member of the Association for Size Diversity and Health (ASDAH), Dec. 31, 2009

[None received as of Jan. 6, 2009]