Expert Commentary

Obesity and weight-related deaths in 195 countries over 25 years: A new study

An estimated 603.7 million adults and 107.7 million children worldwide were obese in 2015, according to new estimates published in The New England Journal of Medicine. China and the U.S. had the highest number of obese adults.

(National Human Genome Research Institute)

The issue: In recent decades, Americans have packed on more weight, creating a public health crisis and prompting various government agencies to launch programs aimed at encouraging adults and children to exercise and eat healthier foods. Excess weight can cause or contribute to a range of serious health problems, including diabetes, high blood pressure and heart disease, according to the National Institutes of Health.

About 38 percent of U.S. adults aged 20 and older are obese as are more than 17 percent of children aged 6 to 11, federal data shows. (To understand how doctors determine whether someone is obese or simply overweight, look at this explainer from the U.S. Centers for Disease Control and Prevention.)

A new study examines the worldwide increase in the number of people who are overweight or obese and how the trend has impacted global health.

An academic study worth reading: “Health Effects of Overweight and Obesity in 195 Countries over 25 Years,” published in The New England Journal of Medicine, June 2017.

About the study: A large research team led by Ashkan Afshin of the University of Washington’s Institute for Health Metrics and Evaluation analyzed data from hundreds of sources to gauge the prevalence of overweight and obesity in 195 countries and how that changed between 1980 and 2015.

Researchers also used data from 1990 to 2015 to quantify the prevalence of disease and death among individuals with a high Body Mass Index (BMI) – a value based on a person’s weight and height that indicates body fatness.

Key findings:

  • In 2015, an estimated 603.7 million adults and 107.7 million children worldwide were obese. That represents about 12 percent of all adults and 5 percent of all children.
  • The prevalence of obesity doubled in 73 countries between 1980 and 2015 and continuously increased in most of the other countries.
  • China and India had the highest number of obese children. China and the U.S. had the highest number of obese adults.
  • Excess body weight accounted for about 4 million deaths — or 7.1 percent of all deaths — in 2015.
  • Almost 70 percent of deaths related to a high BMI were due to cardiovascular disease.
  • The study finds evidence that having a high BMI causes leukemia and several types of cancer, including cancers of the esophagus, liver, breast, uterus, ovary, kidney and thyroid.
  • In rich and poor countries, obesity rates increased, indicating “the problem is not simply a function of income or wealth. Changes in the food environment and food systems are probably major drivers. Increased availability, accessibility, and affordability of energy-dense foods, along with intense marketing of such foods, could explain excess energy intake and weight gain among different populations. The reduced opportunities for physical activity that have followed urbanization and other changes in the built environment have also been considered as potential drivers; however, these changes generally preceded the global increase in obesity and are less likely to be major contributors.”

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