rel="nofollow" href="#ulink_2d1feb3f-3135-5e0b-89ac-28faf8ef2c5d">Figure 2.1 Prevalence of obesity (body mass index ≥30 kg/m2) among adults in the United States in 2011 and 2018 [29]. Data are from the Behavioral Risk Factor Surveillance System, a telephone interview survey conducted by the US Centers for Disease Control and Prevention with state health departments that collects self‐reported information on height and weight. *Sample size <50 or the relative standard error (dividing the standard error by the prevalence) ≥30%.
Source: Centers for Disease Control and Prevention. Adult Obesity Prevalence Maps. October 29, 2019.
Table 2.3 Prevalence of obesity in adults by region and sex, 2016
Source: NCD Risk Factor Collaboration (NCD‐RisC) [1].
| Region | Prevalence of obesity (uncertainty level) | |
|---|---|---|
| Men | Women | |
| Central and Eastern Europe | 21.7 (18.2–25.5) | 26.1 (22–30.4) |
| Central Asia, Middle East, and North Africa | 22.4 (19.4–25.5) | 35.2 (31.9–38.7) |
| East and Southeast Asia | 5.9 (4.2–7.9) | 7.4 (5.7–9.4) |
| High‐income Asia Pacific | 4.9 (3.5–6.5) | 4.3 (3.2–5.6) |
| High‐income Western countries | 29.6 (26.4–32.9) | 29.6 (26.7–32.7) |
| Latin America and the Caribbean | 21.0 (18.1–24) | 29.2 (26–32.5) |
| Oceania | 20.3 (13.9–27.7) | 30.0 (22.9–37.6) |
| South Asia | 3.2 (2.2–4.4) | 6.0 (4.5–7.8) |
| Sub‐Saharan Africa | 4.8 (3.7–6) | 14.6 (12.8–16.5) |
| World | 27.9 (23.7–32.0) | 29.7 (25.6–34.0) |
These differences are particularly pronounced among adult women. For example, in sub‐Saharan Africa, the prevalence of obesity ranges from 7.3% in Ethiopia to 41.0% in South Africa [1]. In 2016, the lowest prevalence of obesity among men and women (Fig. 2.2) was in Vietnam (2.9% in men and 2.7% in women). Men in Uganda, Ethiopia, and Rwanda and women in Japan also had an obesity prevalence below 4%. At the other extreme, for men, Nauru had the highest prevalence of obesity (59.9%), followed by Palau, Cook Islands, and America Samoa, all with a prevalence above 50%. For women, the highest levels were seen in American Samoa (65.3%) with Palau, Cook Islands, and Nauru, all with a prevalence above 60%. Outside Oceania, men in the United States (36.5%), Kuwait (34.3%), and Qatar (33.5%) had the highest levels of obesity, and women in Jordan and Qatar (both 46%). Of the 390 million women with obesity worldwide, 12.5% live in the United States and 9.8% in China. Of the 281 million men with obesity worldwide, 15.6% live in the United States and 12.5% in China.
Similar to adult obesity, there has been a global effort to provide reliable and detailed estimates of the worldwide epidemic of excess weight in children and adolescents [1,11,46,47]. Overall, while adult women have higher levels of obesity than men, for children, the opposite is true: boys have higher levels of obesity than girls. The exception to this is sub‐Saharan Africa, wherein a majority of countries have a higher prevalence of obesity among girls compared to boys. Globally, the prevalence of overweight for children under 5 years rose from 4.8% in 1990 to 5.9% in 2018 [46]. In particular, estimates for 2 to 4 year‐olds showed that between 1980 and 2015, the prevalence of obesity increased from 3.9 and 3.7% to 7.2 and 6.4% in boys and girls, respectively, with the highest level observed in American Samoa where one out of every two children in this age group had obesity (Fig. 2.3) [11]. One in three girls in Kiribati and more than one in four in Samoa and Kuwait had obesity. For boys, the second highest prevalence of obesity in this age group was in Kuwait, followed by Qatar and Kiribati. North Korea, Eritrea, Bangladesh, and Burundi had the lowest prevalence of obesity for both boys and girls.
With respect to global patterns of obesity among children and adolescents over the age of 5 years, the obesity prevalence in 2016 was 5.6% in girls and 7.8% in boys compared to 0.7% and 0.9%, respectively, in 1975 [1]. Compared to four decades ago, when the levels of obesity among children and adolescents were below 1% in the majority of the regions (the highest level of around 4% was observed in high‐income Western countries), the 2016 regional levels are above 10% in the majority of the regions for both boys and girls with the highest level observed in high‐income Western countries (13.3% and 16.8% for girls and boys, respectively). For boys, the eight countries with the lowest levels of child and adolescent obesity (<1%) were all in sub‐Saharan Africa (Fig. 2.4). For girls, 11 countries from low‐, middle‐, and high‐income regions had a prevalence below 2%. At the other end of the spectrum, one in three children in Palau, Cook Islands, and Nauru had obesity. The countries with the greatest increase over time in the prevalence of obesity were Botswana, Lesotho, and Cambodia (6‐ to 7‐fold increase per decade for both sexes combined and more than a 10‐fold increase for boys in Botswana). Of the almost 125 million boys and girls with obesity worldwide, 23.0% are living in China, 11% in the United States, and almost 6% in India.
The gender gap in childhood obesity has been highlighted in several studies. For example, among children and adolescents in Turkey, boys are much more likely to have obesity than girls, and the increase in prevalence since 1990–1995 has been much more marked among boys than girls [48]. Similarly, among children under 5 years of age in Indonesia, boys are more likely to be overweight than girls [49], and in Thailand, the prevalence of overweight is consistently higher among boys than among girls [50,51]. An analysis of Demographic and Health Survey data collected since 2010 from 26 countries, including Democratic Republic of Congo (DRC), Ethiopia, Tanzania, and Nigeria, also found that boys were more likely than girls to have obesity [52]. This is not the case in South Africa: from 2002 to 2008, the prevalence of overweight increased from 6.3% to 11.0% in boys and from 24.3% to 29.0% in girls, and the prevalence of obesity increased from 1.6% to 3.3% and 5.0% to 7.5% in boys and girls, respectively [53].
Overall, the increase in the average BMI has largely corresponded to an increase in the prevalence of obesity more than a reduction in the prevalence of underweight [2]. The persistence of different forms of undernutrition accompanied by the increased levels of overweight and obesity have led to the double burden of malnutrition. The double burden of malnutrition is defined as the simultaneous manifestation of both undernutrition and overweight or obesity at the level of a country, community, household, or even an individual [54]. Undernutrition can include underweight, but also stunting (short length or height‐for‐age), and micronutrient deficiencies such as anemia. Currently, the double burden of malnutrition is affecting mostly low‐ and middle‐income countries, in particular, sub‐Saharan Africa, South Asia, and East Asia and the Pacific regions. Based on the 2020 Global Nutrition Report, of 143 countries for which data on levels of stunting among children under 5 years of age, anemia among women of reproductive age, and overweight (including obesity) in adult women were available, 87% experience high levels