Myth No. 1 Obesity results from lifestyle choices. Almost half of Americans think obesity, defined as a body mass index (BMI) of at least 30, is a reflection of poor exercise and diet choices, according to a survey conducted in 2018 by the University of Chicago. In 2020, an international group of experts in obesity medicine reported that many health-care providers also consider weight gain to be a failure of personal responsibility, associated with an inability to stick with a treatment plan. But the most up-to-date research indicates that the causes of obesity are complex and cannot be explained solely by calories in and out based on diet and exercise. Calorie absorption, or energy derived from consumed food, varies among individuals, and is determined not only by portion size at mealtime but also by factors such as gut microbes, hormones, digestive enzymes and nerve signals. When it comes to burning calories, metabolism is a major player. And there is growing evidence that genetics, sleep deprivation, medications, stress and even the environment a person was exposed to in utero can contribute to unhealthy weight gain. Myth No. 2 Obesity is not a disease. The American Medical Association’s decision to classify obesity as a disease in 2013 went against the recommendations of its own Council on Science and Public Health. Members of the council did not believe that obesity met the definition of a disease, thought this classification would have little bearing on treatment and were concerned it could result in a decrease in personal responsibility. The 2015 ACTION study, which examined barriers to obesity care, noted that health-care providers do not consistently make formal diagnoses of obesity, suggesting that many do not consider it to be a disease.
But obesity is a disease, under the AMA’s definition, because it results in “impairment of the normal functioning of some aspect of the body.” People with obesity have adiposopathy, or “sick fat,” which contributes to abnormal responses from the glands and immune system, resulting in an increased risk for diabetes, high blood pressure, high cholesterol and fatty liver disease. This abnormal immune response is evident as covid-19 takes an inordinate toll on those who are obese. Since obesity has been recognized as a disease, treatment options have increased significantly with new medications and improved guidelines. These treatments augment, but do not remove the need for, changes in diet and physical activity. Additionally, insurance companies are slowly revising their policies to provide coverage for obesity management. Myth No. 3 Dieting and exercise will reverse severe obesity.
The 2019 Attitudes, Stigma and Knowledge Study, a survey of the general population in the United States, Britain, Australia and New Zealand, reported that 80 percent of the population believed that lifestyle intervention including diet and exercise were the cure for severe obesity. It also found that 52 percent of health-care providers surveyed from 77 countries believed the same. The reality TV show “The Biggest Loser” is based on this premise as well. But there is growing evidence that diet and exercise alone are usually ineffective in decreasing and maintaining a lower BMI, particularly for people with severe obesity, defined as a BMI of 40 or more. In fact, weight loss causes hunger to increase and metabolism to slow down, which can lead to weight regain. Most of the contestants on “The Biggest Loser” have ended up gaining a significant amount of weight back. Medications can complement diet and exercise to enable individuals with severe obesity to improve their health. Another effective treatment is weight-loss surgery, which also results in metabolic body changes that significantly decrease the risk of heart disease and diabetes. Myth No. 4 It’s just ‘baby fat.’
Because early childhood is a period of rapid growth and development, it is often assumed that young children who are obese do not remain obese. As pediatricians, we often hear parents say that “it’s just baby fat” and that their children will outgrow being overweight. Although childhood obesity doesn’t always result in obesity in adulthood, most children do not outgrow their weight problem. Only about 17 percent of preschool-age children who are overweight or obese return to a normal weight by the time they start middle school, a 2015 study in Clinical Pediatrics found. Other studies show that childhood obesity is a major predictor of whether a person will become an obese adult. Compared with adult-onset obesity, the consequences of obesity that starts in childhood may be more severe because the child has the disease for more years, leading to more adverse health consequences. Myth No. 5 I can be both fit and fat.
The cover of Cosmopolitan UK magazine recently featured women of different sizes and a headline declaring “This is healthy!” An article in March in Good Housekeeping quoted a writer who claimed, “Your body is the size that it’s supposed to be.” These messages are aimed at reducing shame among overweight people — a worthy goal. Some earlier studies did appear to show that cardiovascular fitness mitigates the risk of heart disease, even among people with obesity. But more recent research may overturn these findings. A January study in the European Journal of Preventive Cardiology found that while the odds of diabetes and hypertension decreased as physical activity increased, adults who were overweight and obese were at greater risk for heart disease than their normal-weight peers, regardless of activity level. Other recent studies have found that although being fat and unfit were risk factors for death, being fit did not reverse the increased risks of obesity. BMI was more important than physical activity in predicting negative health outcomes.