The World is Getting Fatter*
For the first time in human history the number of overweight people in the world outnumbers the number of underweight according to the World Health Organization. About 2 billion people are overweight and one third of them are obese. Over the last 40 years, obesity has been increasing around the world in countries where only malnutrition existed previously. This has been called the Global Nutrition Transition. This change has been linked to several factors including urban population growth relative to rural populations and the global spread of processed snack foods high in sugar, fat, and salt through traditional groceries and through fast food restaurants. The more recent increases in obesity in low- and middle-income countries are now being tracked and carefully documented.
Overweight especially expressed as excess internal abdominal fat has been associated with common health problem. Overweight is as least as common as obesity. For example in the United States, 1/3 of the population is obese and 2/3 are overweight or obese. As a practical matter, body weight and height are surveyed to generate information on obesity trends. These data are an indication of a public health trend around the world, but in any individual excess body weight can be fat or lean. Body Mass Index or BMI is calculated as the height divided by weight squared. In the U.S. data on the common occurrence of obesity used a BMI of about 27 as the cutoff for defining obesity. Most doctors and dietitians use a BMI of 30 as the definition of obesity and a range of 25 to 30 to define overweight. Population scientists typically pick a single value such as a BMI of 27 for a particular population with everyone above that BMI considered obese and everyone below that BMI normal or overweight.
In countries such as India and China, where obesity-associated conditions are being seen with increased frequency, individuals with obesity-associated health issues often have a normal range Body Mass Index. Some population scientists have simply used a lower BMI number to define obesity in Asia and South Asian countries including India and China. However, individuals even below the cutoff numbers with normal range BMI can have obesity-associated conditions quite commonly. It has been estimated that abnormal control of blood sugar levels may affect up to half of the population of China. Data are not available for India, but given the population size of these two countries, they can be defined as the epicenter of the global obesity epidemic.
Within urban areas such as Seattle, Washington, the distribution of obesity is closely linked to income and property values with the greatest number of individuals affected in poorer areas of the city where more fast food restaurants, convenience markets are found in combination with fewer areas for safe exercise. These condition set up a perfect storm for increased adult and childhood obesity. Based on the existing trend data and the surveys linking obesity with a range of common age-related health problems, it is reasonable to describe obesity as a global public health epidemic that affects the health and quality of life of people around the world.
*World Health Organization Obesity and Overweight Fact Sheet updated June 2016 accessed at http://www.who.int/mediacentre/factsheets/fs311/en/ 10/24/16
*Centers for Disease Control and Prevention Adult Obesity Facts September 1 , 2016 accessed at https://www.cdc.gov/obesity/data/adult.html 10/24/16