Massive global analysis: South Africa’s children are too short and too fat

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Young South African children are too short and too fat, concludes a massive analysis pooling data from more than 2,000 studies in 200 countries with a study population of 65m people, write Dr Chantell Witten and Prof Salome Kruger for Spotlight.

Witten is at based the University of the Free State’s Faculty of Health Sciences, Division of Health Science Education. Kruger is a Professor at the North-West University’s Centre of Excellence for Nutrition.

They write:

“Tall as trees” sounds very clichéd but it may not apply to children in many sub-Saharan African countries, according to a study in The Lancet reporting on children’s height and weight changes over the past thirty years.

The Lancet article pooled data from over two thousand studies from two hundred countries with a study population of 65 million participants and reported on the projected changes of height and body-mass index (BMI) of school-aged children and adolescents from 1985 to 2019.

The data showed that the unhealthiest changes—gaining too little height and/or too much weight for their height occurred in many countries in sub-Saharan Africa, including South Africa, as well as in New Zealand and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls.

Growth measured in height and weight has long been recognised as a measure of the health of individuals, hence part of the reasoning for the promotion of routine growth monitoring for children under five years of age. In South Africa, every child is presented with a Road to Health Booklet to record and monitor their weight and height measures from birth. Mothers and caregivers are encouraged to visit their health facility for monthly growth monitoring to track their child’s growth and development as a proxy for health.

A major public health concern

Malnutrition identified in the failure to grow in height and weight is a major public health concern worldwide. In South Africa, 27% of children younger than five years are too short for their age and in the same age group, 15% are too fat. These indicators serve as proxies for the state of overall health. As reflected in the Lancet article, young South African children are too short and too fat.

Our adolescent nutrition profile does not paint a much better picture, with 6.1% males and 16.7% females in the age group 15-19 years overweight and their average height below the global average of 1.62m.

The Lancet reported that 19-year-old boys in 11 countries throughout Asia, Latin America, and sub-Saharan Africa had the same mean height as that of Dutch boys aged 13 years. In many countries in sub-Saharan Africa, with emerging economies, the height of children and adolescents, especially boys, has on average stagnated or become shorter since 1985. This points directly to the increasing levels of poverty driving the vicious cycle of malnutrition as households and communities struggle to access adequate and sufficiently nutritious food.

The Lancet reported that the largest improvements in average height of children over the 35-year period were seen in emerging economies such as China, South Korea and some parts of southeast Asia. For example, 19-year-old boys in China in 2019 were 8 cm taller than in 1985, with their global rank changing from 150th tallest in 1985 to 65th in 2019. Over the same period, the average height of South African girls stagnated, while boys gained only around 2 cm. Nineteen-year-old South African girls had the same average height as 12-year-old Dutch girls, while South African boys of the same age had the average height of 14-year-old Dutch boys.

South Africa is mentioned in the report as one of the countries where children compared fairly well with international growth references at the age of five years, but by the time they reached 19 years, they fell behind due to insufficient growth in height during school-age years. While little or no height was gained per year of age, the girls in particular gained weight, so that the average weight of South African girls in each age group was markedly higher after 2010 than in the 1980s and was in the overweight range at age 19 years.

Falling behind

The Lancet report also highlighted that while children in some countries grow healthily to age five years, they fall behind in the school years in terms of growth in length. This highlights that there is an imbalance between investment in improving nutrition in pre-schoolers, and in school-aged children and adolescents. This issue was especially important during the COVID-19 pandemic when schools were closed throughout the world, and many poor families are unable to provide adequate nutrition for their children. This recognition that school feeding is an important and integral intervention to promote and sustain child nutrition, prompted civil society in South Africa to approach the courts to force government to reinstate the national school nutrition programme.

While many school-aged children do not have access to adequate nutritious food for linear growth and physical development, they seem to have high enough intakes of sweetened cold drinks and cheap snack foods to gain excessive weight. Some of these cold drinks and snacks are even available in the school environment at low cost. This is probably an important driver of the weight gain reported in South African school-age girls.

Ensure food security

The Lancet report re-affirms the imperative to sustain adequate food and nutrition support throughout the critical stages of life including during pregnancy, early childhood, adolescent and adult years to consolidate and reap the benefits gained in food and nutrition interventions and investments in infants and children younger than five years. This is imperative because adolescents and women of child-bearing age are the future parents of the next generation of children. Mothers with poor nutritional status will bear children with poor nutritional status and this is a lost and costly opportunity as malnutrition castes a long shadow into the future robbing individuals, communities and countries of health, well-being and development.

If we are to improve child health and nutrition, governments need to ensure food security. Food security is defined as all people at all times having physical and economic access to adequate amounts of nutritious, safe, and culturally appropriate foods. This will help children grow taller without gaining excessive weight for their height.

To achieve these goals, South Africa needs policies to support an enabling environment, with restricted access to unhealthy foods and drinks and more access to facilities in the community and in the school environment for safe play and sports.


The Lancet study


Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Published: 7 November 2020



Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents.


For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence.


We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls.


The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks.


Wellcome Trust, AstraZeneca Young Health Programme, EU.


Full Spotlight report Full The Lancet study (Open Access)

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