Overweight and obese adults
Globally, overweight and obesity is a major public health concern, and there are more overweight or obese than underweight adults. In 2016, 39% men and 39% of women aged 18+ were overweight and 11% of men and 15% of women were obese. Thus, nearly 2 billion adults worldwide were overweight and, of these, more than half a billion were obese. Both overweight and obesity have shown a marked increase over the past four decades (WHO, 2018a). Obesity is a known risk factor for numerous health problems, including hypertension, high cholesterol, diabetes, cardiovascular diseases, respiratory problems (asthma), musculoskeletal diseases (arthritis) and some forms of cancer, and mortality also increases progressively once the overweight threshold is crossed (Sassi, 2010). Social determinants of health such as poverty, inadequate water and sanitation, and inequitable access to education and health services underlie malnutrition. A key driver of the increasing obesity epidemic is a changing food environment, in which nutrient poor and energy dense processed foods are aggressively marketed, readily available and often cheaper than healthier alternatives. The economic priorities and policies that promote consumption-based growth, and the regulatory policies that promote market and trade liberalisation are increasingly regarded as contributing to the global rise of obesity too (Swinburn et al., 2011).
In Pacific countries, at least one adult female in four was obese in 2016, five times the rate observed in Japan and Viet Nam (Figure 4.15, left panel). In high and upper-middle income countries, two adult females in five were overweight in 2016, whereas the average prevalence for lower-middle and low income countries was lower at 32.7% (Figure 4.15, left panel). More than one adult male in four was obese in Fiji, New Zealand and Australia, and more than half of the adult males are overweight in Mongolia, Australia, New Zealand and Fiji (Figure 4.15, right panel). In high income and upper-middle income countries, at least two adult males in five were overweight in 2016, while the average prevalence reported for lower-middle and low income countries was lower at 27.7% (Figure 4.15, right panel).
Since 2010, the share of overweight people has increased in all Asia-Pacific countries and territories in study, in particular among males in Viet Nam, Lao PDR, Thailand and Indonesia (Figure 4.16). The prevalence of obesity is growing even more rapidly, in particular in Viet Nam and Lao PDR among both females and males (Figure 4.17). In developing countries obesity is more common among people with a higher socioeconomic status, those living in urban regions and middle-aged women. In developed countries, obesity is increasing among all age groups, and is associated with lower socioeconomic status, especially among women (Sassi, 2010).
The most frequently used measure of underweight, overweight and obesity for adults is the Body Mass Index (BMI). This is a single number that evaluates an individual’s weight in relation to height, and is defined as weight in kilograms divided by the square of height in metres (kg/m2).
Based on the WHO classification, adults with a BMI below 18.5 are considered to be underweight/thinness and 25 or over are overweight. Adults who have a BMI of 30 or over are defined as obese.
In many countries, self-reported estimates of height and weight are collected through population-based health surveys while in Australia, Japan, the Republic of Korea and New Zealand, health examinations measure actual height and weight. These differences limit data comparability. BMI estimates from health examinations are more reliable, and generally result in higher values than from self-report surveys.