More than 40 percent of adults in the United States qualify as obese, and an elevated body mass index has been shown to be a major risk factor for developing severe symptoms of covid-19. Unfortunately, stigma has made people with obesity reluctant to seek health care, including the coronavirus vaccines. To overcome this stigma, we need to better understand the true causes of obesity.
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.
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.