Obesity threatens public health and is associated with decreased life expectancy and quality of life. Childhood obesity mostly continues into adulthood and leads to non-communicable diseases (NCDs) like diabetes, cardiovascular diseases and cancer at a younger age. Moreover, with the worldwide spread of severe coronavirus disease 2019 (COVID-19), obesity and impaired metabolic health emerged as important determinants of severe COVID-19 illness . Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016 with a prevalence among this age range from just 4% in 1975 to just over 18% in 2016 . Once considered a high-income country problem, the prevalence of childhood obesity is now rising in low- and middle-income countries despite continuing levels of undernutrition . Therefore, childhood obesity prevention is one of the greatest challenges of the 21st century and should be treated as a high priority.
Obesity is multifactorial combining environmental, behavioural, biological and genetic factors.
However, it is recognised that the main drivers of the current obesity epidemic are related to changing food environments and food systems with an increased availability of inexpensive, energy-dense and ultra-processed foods and beverages, alongside reduced physical activity . For the first time in 2019, a study provided evidence that ultra-processed diets cause over-eating and weight gain and are fuelling the obesity pandemic . Worldwide, 42% of school-going adolescents drink carbonated soft drinks at least once a day and 46% eat fast food at least once a week . There is also a strong association between deprivation and obesity in children, with the prevalence of childhood obesity in 2019, being twice as high in the most deprived areas of England compared to the least deprived . Local authorities with a higher deprivation score have a greater density of fast–food outlets and lower levels of fruit and vegetable consumption, with a growing body of evidence showing an association between exposure to fast–food outlets and obesity [8,9].
This global epidemic will have consequences beyond the disease itself. Psychiatric and psychosocial disorders in childhood are a real concern. Obesity in childhood is a strong indicator of adult obesity with, increased risk of developing NCDs later in life. It also has major economic and social costs, stretching the health systems as well as later reduced economic productivity . According to Charlotte Gornitska (UNICEF), the economic impact is estimated to be US$2 trillion, or 2.8% of the world’s GDP .
Policy: What works
A review of different national government policies to combat childhood obesity showed that most governments have top-down approaches, with higher taxes and marketing restrictions on HFSS (High in Fat, Sugar or Salt) food and beverages, food labelling, school food regulation, national dietary and physical activity guidelines and social marketing programs to encourage healthy lifestyle. Although these policies go in the right direction they are not sufficient to achieve significant reductions in childhood obesity in most countries . A Cambridge study analysing English obesity policies over the last thirty years has shown that policies which make high demand on individuals to change their behaviour rather than shaping external influences fail to reduce obesity prevalence and health inequalities . Back in 2007, the Foresight’s report on obesity concluded that systemic changes were needed. To tackle the global crisis of childhood obesity, top-down approaches needs to be combined with community-based approaches targeting more deprived areas which are at greater risk of obesity. This means support for families and parents, engagement with local stakeholders and businesses at a local level but also enabling the capacity-building of local communities to help improve environment for children . Obesity prevention needs a whole-society approach to building healthier food environments.
The approach needs to be multi-sectoral: spanning education, health, employment and social protection, with a long-term view to making our environments child-friendly and health-promoting.
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 Di Cesare, M., et al., 2019. The epidemiological burden of obesity in childhood: a worldwide epidemic requiring urgent action. BMC Medicine. 17 :212. Accessed 27 February 2021
 Hall et al.,2019. Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake. Cell metabolism 30,67-77. Accessed 28 February 2021.
 Gornitska,C.P., Obesity isn’t an unstoppable trend – here’s what we can do differently .world economic forum. Accessed 2 March 2021
 Theiz,R.Z and White,M., 2021. Is Obesity Policy in England Fit for Purpose? Analysis of Government Strategies and Policies, 1992–2020. The MilbankQuaterly. Vol. 00, No. 0. pp. 1-45.
 Public Health England, Adult Obesity/Child Obesity and Adult Diet slide sets https://www.gov.uk/guidance/phe-data-and-analysis-tools#obesity-diet-and-physical-activity
 Donin., A.S, Nightingale., C.M, Owen., C.G, et al.2018. Takeaway meal consumption and risk markers for coronary heart disease, type 2 diabetes and obesity in children aged 9–10 years: a cross- sectional study Archives of Disease in Childhood .103:431-436. Accessed 1 March 2021
 Musowo,N., 2019 , International policies to reduce childhood obesity – a Health Action Campaign review. Health action campaign. Accessed 2 March 2021