Obesity

Obesity, according to the World Heath Organization, is the “abnormal or excessive fat accumulation that presents a risk to health.” This is undeniable, but perceptions of obesity, healthiness, and beauty have radically changed over time, changing in turn the debate about fatness. But however one views it, obesity is becoming an increasingly serious concern, as obesity rates rise and studies show a prominent tie between obesity and a host of potentially fatal health issues, including a tie to 13 kinds of cancer.[1] [60]

Obesity and BMI

Body Mass Index (BMI) is an estimate of total body fat. For adults age 20 and older, a BMI below 18.5 is considered underweight, between 18.5–24.9 is considered healthy, 25–29.9 is overweight, 30 or higher is considered obese, and over 40 severely obese.[1] [2]

BMI is just one way to estimate total body fat. According to Encyclopaedia Britannica, “BMI is defined as weight in kilograms divided by the square of the height in metres.” The number, however, is not a direct measure of body fat, and a skinfold caliper, a hand-held device that pinches the skin and measures body fat, can offer a quick, affordable, and more accurate measurement. While BMI has been used in clinical settings for years, in 2023 the American Medical Association urged healthcare professionals not to rely solely on BMI as a measure of a patient’s health. [3] [4]

You may calculate BMI at the CDC website.

BMI, first known as the Quetelet Index, was created by Belgian astronomer, sociologist, and statistician Adolphe Quetelet in 1832 to determine the “homme moyen,” or the “average man.” Quetelet was not looking to diagnose health concerns in relation to body weight for individuals. He was, instead, making calculations of population health for the government for its allocation of resources, and he based his calculations on a group of western European white men.[44] [45] [46] [47] [48] [49] [50] [51] [52] [53]

Pinpointing the weight of the normal, “average” man was pursued in the United States by a surprising source: the insurance industry. As Dr. Garabed Eknoyan has written,

The first alarm against excess weight was sounded by the insurance industry. Actuarial studies that linked excess weight to increased mortality began to appear in the early years of the twentieth century. By the 1920s, studies on the experience of industrial policyholders of the Metropolitan Life Insurance Company were analyzed for differential mortality by weight and associated with specific diseases by Louis I. Dublin (1882-1969), a statistician and vice-president of the company.

What Dublin noticed was that heavier people, folks fatter than the “norm,” were filing more insurance claims, leading him to establish weight tables for clients, placing them in small, medium, and large categories.[61] [69]

Further analyses of weight categories followed in subsequent decades. Building upon the 19th-century Quetelet Index, physiologist Ancel Keys rebranded it and its formula as the “Body Mass Index” (BMI) in 1972, recommending it as the most efficient measure of obesity for population studies. Like Quetelet, he did not promote the use of his index as an individual health marker.[44] [45] [46] [47] [48] [49] [50] [51] [52] [53]

In 1985, the National Health and Nutrition Examination Survey (NHANES) combined health insurance weight tables and BMI to produce the calculations we all know today. BMI is used by health professionals to determine if a person over age 20 is underweight (a BMI under 18.5), a healthy weight (between 18.5 and 24.9), overweight (between 25 and 29.9), or obese (30 and over). But many have found the use of BMI as the primary indicator of body fat to be problematic, because the measurement fails to consider the individual. As journalist Keith Devlin notes, BMI does not take into consideration waist circumference, race, gender, or age, and it

makes no allowance for the relative proportions of bone, muscle and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI. Thus, athletes and fit, health-conscious movie stars who work out a lot tend to find themselves classified as overweight or even obese.[44] [45] [46] [47] [48] [49] [50] [51] [52] [53]

As BMI falls more out of favor, researchers and doctors are looking for new ways to measure obesity. One method would use genetic data to predict obesity risk in children, allowing for early intervention. Another method would add waist circumference, waist-to-hip ratio, and waist-to-height ratio to BMI calculations. According to this revised calculation, an estimated 75.2 percent of Americans are “obese” (including nearly everyone 50 and older) as opposed to only 40 percent when BMI alone is used. These new methods and revised measurements, however, have not been widely utilized, and BMI remains the most widely used and accepted standard, despite its limitations, for assessing obesity.[62] [68]

Obesity rates

According to BMI, roughly 40 percent of Americans (2 in 5 people) are obese today. This high rate, however, is a recent development. In the mid-1970s, the U.S. obesity rate was only about 14 percent. The Centers for Disease Control and Prevention (CDC) first collected data on weight from each U.S. state individually in 1994 when the obesity rate was 19 percent or lower in each state. During the lockdowns associated with the COVID-19 pandemic, the U.S. obesity rate rose by 3 percent between March 2020 and March 2021. By 2023, all U.S. states and territories had an obesity rate over 20 percent; the Midwest (36 percent) and South (34.7 percent) had the highest rates of obesity, followed by the West (29.1 percent) and the Northeast (28.6 percent); and three states (Arkansas, Mississippi, and West Virginia) had obesity rates of 40 percent or greater (West Virginia had the highest, at 41.2 percent). As the CDC reported in 2024, more than 2 in 5 U.S. adults (40 percent of the adult population) are obese.[8] [9] [10] [11] [12] [56] [58]

As Trust for America’s Health explained, “Obesity is multifactored and involves more than individual behavior.” Among the factors the organization cites for contributing to obesity is living in communities (so-called “food deserts”) with many fast-food establishments and convenience stores but limited access to healthier, affordable food options, such as those widely available in larger, full-service supermarkets. This often leaves many lower-income families in lower-income towns and neighborhoods eating food that costs less but which is high in calories and low in nutritional value.[13]

According to the WHO’s World Bank calculations for 2022, the United States was the 15th most obese jurisdiction in the world. This calculation, however, separated U.S. territories from the main American calculation, which is significant, because islands rank among the most obese areas of the world. In fact, the 11 locations in the world with the highest obesity rates are all islands: American Samoa (75.2 percent), Tonga (71.7 percent), Naoero (69.9 percent), Tuvalu (64.2 percent), Samoa (62.4 percent), French Polynesia (48.1 percent), the Bahamas (47.3 percent), Micronesia (47.1 percent), Kiribati (46.3 percent), Marshall Islands (45.9 percent), and St. Kitts and Nevis (45.6 percent). Overall, according to the WHO, 82 of the 196 jurisdictions of the world, or 41.8 percent, had obesity rates over 25 percent. [14] [57]

The WHO organization declared obesity a “global epidemic” in 1997, stating “obesity is a chronic disease, prevalent in both developed and developing countries, and affecting children as well as adults. Indeed, it is now so common that it is replacing the more traditional public health concerns, including malnutrition and infectious disease, as one of the most significant contributors to ill health.” Given the rising rates of obesity, the epidemic is only getting worse. [15]

Some 43 percent of American women and 37 percent of men describe themselves as very or somewhat overweight, according to a December 2025 Gallup poll. Meanwhile, 58 percent of American women and 46 percent of men would like to lose weight, and 30 percent of women and 22 percent of men are “seriously trying” to do so.[66]

However, Gallup also found that obesity rates have decreased from a peak 39.9 percent in 2022 to 37.0 in 2025. Authors Dan Witters and Mary Page James attributed the three-year drop, at least in part, to the rise of GLP-1 weight-loss drugs—5.8 percent of American adults reported using such drugs at the beginning of 2024, 12.4 percent reported doing so in mid-2025. This three-year drop in obesity rates is “a statistically meaningful decrease,” concluded the authors, “representing an estimated 7.6 million fewer obese adults compared with three years ago.”[67]

Obesity defined as a disease

By 2013, most major health organizations and agencies had defined obesity as a disease, including American Academy of Family Physicians, American College of Cardiology, American College of Gastroenterology, American Heart Association, American Medical Association (AMA), Food and Drug Administration (FDA), National Institutes of Health (NIH), and Obesity Society. Even the Internal Revenue Service (IRS) allows Americans who are medically diagnosed as obese to claim tax deductions for doctor-prescribed treatments. [16] [17] [18] [19] [20] [21] [22] [23]

However, defining obesity as a disease is not universally accepted. As an international commission of 58 experts explained in The Lancet Diabetes & Endocrinology in January 2025,

Despite evidence that some people with excess adiposity [fat] have ill health due to obesity, obesity is generally considered a harbinger of other diseases, not a disease in itself. The idea of obesity as a disease remains therefore highly controversial. In addition, current BMI-based measures of obesity can both underestimate and overestimate adiposity and provide inadequate information about health at the individual level. [54] [55]

What nearly everyone can agree on is that obesity is a global epidemic. The question more frequently debated is whether obesity should be treated as a disease.

U.S. obesity levels by state

Obesity is widely determined by BMI (Body Mass Index) measurements. Someone with a BMI of 30 or more is considered obese. According to the Trust for America’s Health, adult obesity rates exceeded 35 percent in 19 states in 2024, meaning at least 35 percent of the adult population in the state was obese; in 2011, the oldest comparable data, no state had an obesity rate over 35 percent—only one state, Mississippi, neared that mark at 34.9 percent

Global obesity levels

The United States territory American Samoa was the most obese jurisdiction in the world with obesity affecting 75.2 percent of the adult population in 2022, according to the most recent data available from the World Health Organization (WHO). Vietnam was the least obese country with 2.0 percent of the adult population classified as obese.

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Discussion questions

1. Should obesity be treated as a disease? Why or why not?
2. Should obesity be treated with medication? Why or why not?
3. How can we treat obesity socially? Consider transportation seat sizes, meal portions, and clothing size availability, among other factors that make navigating the world difficult for some. Explain your answer.
4. What questions do you have after reading the debate above? Where might you find answers?
5. What was the most interesting thing you learned from this debate?
6. Consider how you felt about the issue before reading this article. After reading the pros and cons on this topic, has your thinking changed? How and why?. If your thoughts have not changed, explain how and why you better understand the other side of the debate.
7. Push for the position and policies you support by writing local officials, U.S. senators and representatives, or other people in a position to make the change you champion.