Obesity in adults is defined by a body mass index (BMI) of 30 or above. BMI is calculated using a person’s weight and height to create an estimate of the amount of fat in a person’s body. For children and adolescents, the Centers for Disease Control and Prevention (CDC) defines obesity as “a BMI at or above the 95th percentile for children and teens of the same age and sex.” Obesity in adults is not measured against a reference population.
Obesity is taxing on the body and can place people at a higher risk for a variety of health problems, such as heart disease, diabetes, liver disease, high blood pressure, infertility, gallbladder disease, depression, several forms of cancer, stroke, and sleep apnea. During pregnancy, obesity and excessive weight gain increase the likelihood of miscarriage, gestational diabetes, preeclampsia, and complications during labor. As stated by the American College of Obstetricians and Gynecologists, children born to obese mothers face an increased likelihood of birth defects, and may encounter related issues throughout their development and into adulthood.
The CDC has reported that more than one-third of adults (39.8 percent) and more than one-sixth of children ages two to nineteen (18.5 percent) in the United States were considered obesein 2016, leading many health care professionals to identify obesity as a national epidemic. Obesity rates have risen substantially since 1990, when no state had an obesity rate over 15 percent.
In 2016 forty-seven states had obesity rates higher than 25 percent, with the rates of five states exceeding 35 percent. In light of the growing incidence of obesity, health care professionals have warned against normalizing obesity, as doing so can deter obese people from seeking medical help. A 2017 report in the Journal of the American Medical Association(JAMA) stated that the number of overweight and obese Americans attempting to lose weight is decreasing.
In a study of more than 27,000 overweight and obese US adults, 55.6 percent reported trying to lose weight during the initial time period studied, 1988 to 1994, while only 49.2 percent were trying to lose weight between 2009 and 2014. Health care professionals discourage focusing too heavily on weight and body mass, stressing the importance of monitoring other health indicators. Some body positivity activists contend that a person can more effectively address health concerns by accepting their size and concentrating on improving overall health.
Body Mass Index
Though health care professionals, fitness experts, and nutritionists commonly use BMI to appraise how a person’s body size relates to overall health, the measurement possesses some limitations that can result in misleading conclusions because the way body fat is stored can vary depending on a person’s age, gender, and level of muscle or bone mass.
An adult woman who is five feet, four inches tall would have a BMI of 30 at 175 pounds, placing her in the obese category. In comparison, an adult woman who is five feet, seven inches in height and also 175 pounds would have a BMI of 27 and would be categorized as overweight rather than obese. People with a BMI between 25 and 29.9 are considered overweight, while people with a BMI under 18.5 are considered underweight.
Critics have argued against the use of BMI to determine the relationship between a person’s weight and health due to its failure to take into account such factors as the volume difference between muscle and fat. A pound of muscle is denser and takes about four-fifths of the same volume as a pound of fat.
This means that an athlete in good health could be classified as overweight according to his or her BMI. The BMI rating system also does not consider where fat may be concentrated within a person’s body. Therefore, a person with a BMI in the healthy range could still have excess fat in areas that carry higher risk, such as around the midsection, which could lead to health complications such as heart disease.
A BMI in the healthy range also does not guarantee that a person is protected from all physical health concerns. A 2016 study published in the International Journal of Obesity assessed the health of more than 40,000 adults by examining six different metrics for health, including blood pressure and cholesterol. Of these adults, 47 percent who were classified as overweight by their BMI and 29 percent of those classified as obese were found to be healthy when using the other metrics.
Over 30 percent of those classified as having a healthy weight were found to be unhealthy according to other metrics. Regardless of their overall health, individuals with high BMIs who receive health insurance through their employer may be ineligible to receive certain financial incentives, such as lowered premiums, offered as part of workplace wellness programs. Such incentive programs are only offered by a small percentage of large employers and must adhere to provisions within the Affordable Care Act.
Causes and Risk Factors of Obesity
Though obesity most commonly occurs when the body consumes more energy, typically measured in calories, than it expels through normal functioning and physical exercise, researchers have noted that obesity most often results from a combination of factors.
Researchers at the National Heart, Lung, and Blood Institute at the National Institutes of Health (NIH) have found that risk factors for obesity include lifestyle and behavioral habits, unhealthy environments, race and ethnicity, use of certain medications, and genetics. A lack of sleep has also been known to slow metabolism and contribute to excessive weight gain. Men and women store fat differently, which can contribute to different susceptibilities to obesity. Additionally, transgender people face higher rates of being overweight or obese, with 72.4 percent of transgender people found to have BMIs equal to or greater than 25 compared to 65.5 percent of cisgender people.
Environmental contributors include a lack of access to affordable healthy foods and a lack of safe places to exercise. Communities with limited food options, commonly referred to as food deserts, experience higher rates of obesity than people in areas with more diverse options. Likewise, obesity rates are higher in food swamps, or areas where retailers selling fast food and junk food outpace those offering healthier options.
Sedentary work, including most office work, and other jobs with low physical demands contribute to a general lack of exercise. Additionally, long-term unemployment has been linked to obesity. Genetics have also been linked to obesity, but a genetic disposition does not mean someone is certain to become obese and rarely can be identified as the sole cause of a person’s obesity.
In addition to inherited genetic factors, researchers note that family food culture can affect the likelihood of obesity. Generally, families that eat together and eat without the television on have lower rates of obesity.
A 2017 study published in the research journal Obesity identified a link between chronic stress and excessive weight among British men and women age fifty and older. The study found that people report overeating and eating more foods with more sugar, fat, and calories during extended periods of stress. Additionally, cortisol, the stress hormone, can negatively impact metabolism and cause the body to store more fat.
Prevention Strategies and Related Challenges of Obesity
Preventing obesity can be as complex as identifying the causes of the condition. Behavioral and environmental changes can help prevent excessive weight gain. Health care professionals recommend increasing physical activity, reducing the consumption of unhealthy foods, improving sleep, and reducing stress as means to combat obesity. Certain social and economic factors can also present challenges for overcoming obesity, such as a lack of access to affordable and nutritious foods.
A poor diet can also negatively affect brain functioning, leading to a dysfunction in how dopamine, a neurotransmitter associated with pleasure and reward, reacts to food consumption, causing increased cravings for unhealthy foods high in sugar and fat content.
Negative social bias against people who are obese and overweight can commonly result in what has been termed body shaming, also referred to as fat shaming. While some people cite body shaming as a potential motivating factor to help people lose weight, evidence suggests that body shaming can have the opposite effect. In a 2015 study published in the journal Psychological Science, researchers reported that body shaming can increase the likelihood of developing mental health conditions that make it more difficult to lose weight.
In addition, increased social acceptance of diverse body types and the development of community initiatives that encourage self-advocacy and a focus on well-being have been shown to have better outcomes than programs that focus only on weight loss. A 2017 study published in Obesity concluded that people seeking treatment for obesity often internalize prejudices, which could result in an increased risk of stroke, heart disease, and diabetes.
Effects of Obesity
The CDC reports that obesity-related conditions, such as heart disease, stroke, and type 2 diabetes, are among the leading causes of preventable death in the United States. According to the World Health Organization (WHO), about 2.8 million people die each year from complications related to being obese or overweight. The Trust for America’s Health and the Robert Wood Johnson Foundation have predicted that more than half of the US population will be obese by 2030, leading to dramatic increases in the prevalence of obesity-related diseases and health care costs as well as significant losses in economic productivity.
To accommodate the increase in people with obesity, additional expenses need to be incurred. Hospitals must invest in equipment such as larger beds and toilets specifically for obese people. Schools and offices require larger seats and desks. According to the 2016 Gallup-Healthways Well-Being Index, medical expenses related to overweight and obese adults in the United States contribute more than $142 billion in annual health care costs.
Compared to individuals with lower BMIs, people who are overweight pay an additional $378 in annual health care costs while people with obesity typically pay an additional $1,580 each year. People classified as obese also often face biases from health care providers and are at an increased risk of suffering from depression and anxiety.
In addition to the physical health ramifications of obesity, many obese people experience discrimination and encounter weight bias that limits their earning potential. By incorporating weight language in its 1976 civil rights legislation, Michigan is the only state that forbids employers from discriminating against employees or job applicants based on weight.
Discrimination in the hiring process results in obese people losing career opportunities and experiencing longer periods of unemployment between jobs. In the workplace, weight discrimination can result in lower wages for obese and overweight workers, particularly women. An analysis by researchers at the University of Florida and the London Business School determined that women who are obese or overweight may make between $9,000 to $19,000 less than women of average weight, while women who are perceived as thin could receive between $10,000 and $23,000 more annually.
Weight Loss Medication and Bariatric Surgery
Weight-loss surgery or medication can assist some people with obesity who wish to lose weight but are not able to do so effectively through diet and exercise changes. Physicians caution that both can lead to significant adverse events or side effects, however.
The once popular diet medication fen-phen, short for fenfluramine/phentermine, caused heart-valve disease and was pulled off the market in 1997, resulting in more than $21.1 billion in legal costs to American Home Products, the drug company that manufactured and distributed it. Orlistat, sold by prescription as Xenical or over-the-counter as Alli, can cause gastrointestinal side effects such as loose stools, particularly following the consumption of high-fat meals; therefore, a careful diet must be followed when taking this medication.
Other FDA-approved weight loss medications also carry significant risks. Phentermine-topiramate, sold by prescription as Qsymia, has been linked to birth defects. Increased suicidality has been reported in patients taking the combined drugs naltrexone-buproprion, sold by prescription as Contrave. Health care professionals caution that weight loss cannot be accomplished by medication alone and urge patients to follow the medicine’s instructions precisely while remaining in regular contact with their doctors.
Weight loss, or bariatric, surgery has become increasingly popular in the United States, with more than two hundred thousand surgeries performed in 2016, up from an average of sixteen thousand performed annually in the early 1990s. One of the most well-known forms of bariatric surgery is gastric bypass surgery, where a portion of the stomach is sectioned off into a small pouch and reconnected to the lower part of the small intestine to reduce the amount of food absorbed by the body.
Doctors recommend that patients make significant lifestyle changes regarding diet and physical activity after the surgery. A patient who undergoes gastric bypass and who makes the necessary lifestyle changes can typically lose between 65 and 70 percent of their excess weight in the first year following surgery. After the surgery, a patient’s stomach is so small that it can hold only a few ounces of food or liquid at a time.
In addition, patients cannot consume liquids and solid food within a half an hour of each other. Even moderate overeating can cause severe pain and nausea. Patients must follow strict guidelines to ensure they receive proper nutrients and hydration. Other forms of bariatric surgeries, including laparoscopic gastric band surgery and sleeve gastrectomy, also require the patient to make significant lifestyle and diet changes.