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The #1 Cause of Obesity, Says Science

This is what’s causing the obesity epidemic, according to experts. 

Obesity is linked to a number of health conditions such as heart disease, type 2 diabetes, cancer, strokes, and more. According to the CDC, the obesity rate for adults in the U.S went from 30.5% in 1999–2000 up to 42.4% in 2017–2018—and severe obesity increased from 4.7% to 9.2%. But what is causing this dramatic and deeply concerning national epidemic? Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


Sedentary Lifestyle

Young black man reclining on couch and reading tablet
Shutterstock / fizkes

A sedentary lifestyle is a leading cause of disease, disability, and serious health conditions such as obesity. "The results of our investigation show that in sedentary overweight adults who continue to choose a sedentary lifestyle the detrimental effects are worse and more rapid than we previously thought," says Cris Slentz, Ph.D., from Duke University Medical Center. "We probably should not have been surprised since this simply mirrors the increasingly rapid rise in obesity prevalence seen in the U.S., where presently two out of three adults are overweight or obese. On the other hand, participants who exercised at a level equivalent to 17 miles of jogging each week saw significant declines in visceral fat, subcutaneous abdominal fat and total abdominal fat," Slentz continued. "While this may seem like a lot of exercise, our previously sedentary and overweight subjects were quite capable of doing this amount."

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stressed woman

There is extensive research linking long-term stress to obesity, including one study published in the journal Obesity where cortisol accumulation was measured from hair samples. "These results provide consistent evidence that chronic stress is associated with higher levels of obesity," says lead researcher Dr. Sarah Jackson, from University College London Epidemiology and Public Health. "People who had higher hair cortisol levels also tended to have larger waist measurements, which is important because carrying excess fat around the abdomen is a risk factor for heart disease, diabetes, and premature death."

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Poor-Quality Sleep

Woman Lying On Bed

Bad—or not enough—sleep and obesity unfortunately go hand-in-hand—when we don't get good quality sleep, it negatively impacts the part of our brain that regulates appetite. "Obesity develops when energy intake is greater than expenditure. Diet and physical activity play an important part in this, but an additional factor may be inadequate sleep," says Dr Kristen Knutson from the University of Chicago. "A review of the evidence shows how short or poor quality sleep is linked to increased risk of obesity by de-regulating appetite, leading to increased energy consumption… These findings show that sleeping poorly can increase a person's risk of developing obesity, diabetes, high blood pressure or heart disease. Future research should determine whether efforts to improve sleep can also help prevent the development of these diseases or improve the lives of patients with these conditions."

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Obesity and COVID-19

Obesity is linked to a number of dangerous health conditions—including COVID-19. Research shows that being overweight or obese can lead to higher risk of being hospitalized with COVID-19 complications. "We didn't understand early on what a major risk factor obesity was. … It's not until more recently that we've realized the devastating impact of obesity, particularly in younger people," says Anne Dixon, a physician-scientist who studies obesity and lung disease at the University of Vermont. "That may be one reason for the devastating impact of COVID-19 in the United States, where 40% of adults are obese."

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The #1 Cause of Obesity Is…

Man eating an hamburger and driving seated in his car

A poor diet is the leading cause of obesity in the U.S., according to doctors and scientists—and it's not simply a case of calories in, calories out. The type of calories consumed—specifically, processed carbohydrates—are signaling the body to hold onto fat stores. "When comparing the U.S. diet to the diet of those who live in 'blue zones' – areas with populations living to age 100 without chronic disease – the differences are stark," says Leigh A. Frame, PhD, MHS. "Many of the food trends we reviewed are tied directly to a fast-paced U.S. lifestyle that contributes to the obesity epidemic we are now facing. Rather than solely treating the symptoms of obesity and related diseases with medication, we need to include efforts to use food as medicine. Chronic disease in later years is not predestined, but heavily influenced by lifestyle and diet. Decreasing obesity and chronic disease in the U.S. will require limiting processed foods and increasing intake of whole vegetables, legumes, nuts, fruits, and water. Health care providers must also emphasize lifestyle medicine, moving beyond 'a pill for an ill.'" Obesity puts you at risk for severe COVID.  To protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan
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